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<!doctype html> <html lang="en" dir="ltr" class="docs-wrapper plugin-docs plugin-id-default docs-version-current docs-doc-page docs-doc-id-reference/technologies/client/swift" data-has-hydrated="false"> <head> <meta charset="UTF-8"> <meta name="generator" content="Docusaurus v3.6.3"> <title data-rh="true">OpenFeature iOS SDK | OpenFeature</title><meta data-rh="true" name="viewport" content="width=device-width,initial-scale=1"><meta data-rh="true" name="twitter:card" content="summary_large_image"><meta data-rh="true" property="og:image" content="https://openfeature.dev/img/opengraph.jpg"><meta data-rh="true" name="twitter:image" content="https://openfeature.dev/img/opengraph.jpg"><meta data-rh="true" property="og:url" content="https://openfeature.dev/docs/reference/technologies/client/swift"><meta data-rh="true" property="og:locale" content="en"><meta data-rh="true" name="docusaurus_locale" content="en"><meta data-rh="true" name="docsearch:language" content="en"><meta data-rh="true" name="docusaurus_version" content="current"><meta data-rh="true" name="docusaurus_tag" content="docs-default-current"><meta data-rh="true" name="docsearch:version" content="current"><meta data-rh="true" name="docsearch:docusaurus_tag" content="docs-default-current"><meta data-rh="true" property="og:title" content="OpenFeature iOS SDK | OpenFeature"><meta data-rh="true" name="description" content=" <ul> <li>Search for <code>git@github.com:open-feature/swift-sdk.git</code> and click "Add Package"</li> </ul> </li> <li>Clone the repository locally <ul> <li>Clone locally using your preferred method</li> <li>Use the "Add Local..." button to select the local folder</li> </ul> </li> </ol> <p><strong>Note:</strong> Option 2 is only recommended if you are making changes to the client SDK.</p> <h4 class="anchor anchorWithStickyNavbar_LWe7" id="swift-package-manager">Swift Package Manager<a href="#swift-package-manager" class="hash-link" aria-label="Direct link to Swift Package Manager" title="Direct link to Swift Package Manager"></a></h4> <p>If you manage dependencies through SPM, in the dependencies section of Package.swift add:</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">package</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">url</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"git@github.com:open-feature/swift-sdk.git"</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> from</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"0.2.0"</span><span class="token punctuation" style="color:#8dc891">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <p>and in the target dependencies section add:</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">product</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">name</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"OpenFeature"</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> package</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"swift-sdk"</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">,</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="usage">Usage<a href="#usage" class="hash-link" aria-label="Direct link to Usage" title="Direct link to Usage"></a></h3> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token keyword" style="color:#c5a5c5">import</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeature</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token class-name" style="color:#FAC863">Task</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">let</span><span class="token plain"> provider </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">CustomProvider</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// configure a provider, wait for it to complete its initialization tasks</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">await</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">setProviderAndWait</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">provider</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> provider</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// get a bool flag value</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">let</span><span class="token plain"> client </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">getClient</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">let</span><span class="token plain"> flagValue </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> client</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">getBooleanValue</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">key</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"boolFlag"</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> defaultValue</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token boolean" style="color:#ff8b50">false</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token punctuation" style="color:#8dc891">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="features">Features<a href="#features" class="hash-link" aria-label="Direct link to Features" title="Direct link to Features"></a></h2> <table><thead><tr><th>Status</th><th>Features</th><th>Description</th></tr></thead><tbody><tr><td>✅</td><td><a href="#providers">Providers</a></td><td>Integrate with a commercial, open source, or in-house feature management tool.</td></tr><tr><td>✅</td><td><a href="#targeting">Targeting</a></td><td>Contextually-aware flag evaluation using <a href="/docs/reference/concepts/evaluation-context">evaluation context</a>.</td></tr><tr><td>✅</td><td><a href="#hooks">Hooks</a></td><td>Add functionality to various stages of the flag evaluation life-cycle.</td></tr><tr><td>❌</td><td><a href="#logging">Logging</a></td><td>Integrate with popular logging packages.</td></tr><tr><td>❌</td><td><a href="#named-clients">Named clients</a></td><td>Utilize multiple providers in a single application.</td></tr><tr><td>✅</td><td><a href="#eventing">Eventing</a></td><td>React to state changes in the provider or flag management system.</td></tr><tr><td>❌</td><td><a href="#shutdown">Shutdown</a></td><td>Gracefully clean up a provider during application shutdown.</td></tr><tr><td>✅</td><td><a href="#extending">Extending</a></td><td>Extend OpenFeature with custom providers and hooks.</td></tr></tbody></table> <sub>Implemented: ✅ | In-progress: ⚠️ | Not implemented yet: ❌</sub> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="providers">Providers<a href="#providers" class="hash-link" aria-label="Direct link to Providers" title="Direct link to Providers"></a></h3> <p><a href="/docs/reference/concepts/provider">Providers</a> are an abstraction between a flag management system and the OpenFeature SDK. Look <a href="/ecosystem?instant_search%5BrefinementList%5D%5Btype%5D%5B0%5D=Provider&instant_search%5BrefinementList%5D%5Btechnology%5D%5B0%5D=Swift">here</a> for a complete list of available providers. If the provider you're looking for hasn't been created yet, see the <a href="#develop-a-provider">develop a provider</a> section to learn how to build it yourself.</p> <p>Once you've added a provider as a dependency, it can be registered with OpenFeature like this:</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token keyword" style="color:#c5a5c5">await</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">setProviderAndWait</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">provider</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">MyProvider</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <blockquote> <p>Asynchronous API that doesn't wait is also available</p> </blockquote> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="targeting">Targeting<a href="#targeting" class="hash-link" aria-label="Direct link to Targeting" title="Direct link to Targeting"></a></h3> <p>Sometimes, the value of a flag must consider some dynamic criteria about the application or user, such as the user's location, IP, email address, or the server's location. In OpenFeature, we refer to this as <a href="/specification/glossary#targeting">targeting</a>. If the flag management system you're using supports targeting, you can provide the input data using the <a href="/docs/reference/concepts/evaluation-context">evaluation context</a>.</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token comment" style="color:#999999">// Configure your evaluation context and pass it to OpenFeatureAPI</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token keyword" style="color:#c5a5c5">let</span><span class="token plain"> ctx </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">MutableContext</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> targetingKey</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> userId</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> structure</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">MutableStructure</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">attributes</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token string-literal string" style="color:#8dc891">"product"</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">Value</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">string</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">productId</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">setEvaluationContext</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">evaluationContext</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> ctx</span><span class="token punctuation" style="color:#8dc891">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="hooks">Hooks<a href="#hooks" class="hash-link" aria-label="Direct link to Hooks" title="Direct link to Hooks"></a></h3> <p><a href="/docs/reference/concepts/hooks">Hooks</a> allow for custom logic to be added at well-defined points of the flag evaluation life-cycle. Look <a href="/ecosystem/?instant_search%5BrefinementList%5D%5Btype%5D%5B0%5D=Hook&instant_search%5BrefinementList%5D%5Btechnology%5D%5B0%5D=Swift">here</a> for a complete list of available hooks. If the hook you're looking for hasn't been created yet, see the <a href="#develop-a-hook">develop a hook</a> section to learn how to build it yourself.</p> <p>Once you've added a hook as a dependency, it can be registered at the global, client, or flag invocation level.</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token comment" style="color:#999999">// add a hook globally, to run on all evaluations</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">addHooks</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">hooks</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">ExampleHook</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token comment" style="color:#999999">// add a hook on this client, to run on all evaluations made by this client</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain">val client </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">getClient</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain">client</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">addHooks</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token class-name" style="color:#FAC863">ExampleHook</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token comment" style="color:#999999">// add a hook for this evaluation only</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token omit keyword" style="color:#c5a5c5">_</span><span class="token plain"> </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> client</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">getValue</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> key</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token string-literal string" style="color:#8dc891">"key"</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> defaultValue</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token boolean" style="color:#ff8b50">false</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> options</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">FlagEvaluationOptions</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">hooks</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token class-name" style="color:#FAC863">ExampleHook</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">)</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="logging">Logging<a href="#logging" class="hash-link" aria-label="Direct link to Logging" title="Direct link to Logging"></a></h3> <p>Logging customization is not yet available in the iOS SDK.</p> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="named-clients">Named clients<a href="#named-clients" class="hash-link" aria-label="Direct link to Named clients" title="Direct link to Named clients"></a></h3> <p>Support for named clients is not yet available in the iOS SDK.</p> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="eventing">Eventing<a href="#eventing" class="hash-link" aria-label="Direct link to Eventing" title="Direct link to Eventing"></a></h3> <p>Events allow you to react to state changes in the provider or underlying flag management system, such as flag definition changes, provider readiness, or error conditions. Initialization events (<code>PROVIDER_READY</code> on success, <code>PROVIDER_ERROR</code> on failure) are dispatched for every provider. Some providers support additional events, such as <code>PROVIDER_CONFIGURATION_CHANGED</code>.</p> <p>Please refer to the documentation of the provider you're using to see what events are supported.</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token keyword" style="color:#c5a5c5">let</span><span class="token plain"> cancellable </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeatureAPI</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">shared</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token function" style="color:#79b6f2">observe</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">sink </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"> event </span><span class="token keyword" style="color:#c5a5c5">in</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">switch</span><span class="token plain"> event </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">case</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">ProviderEvent</span><span class="token punctuation" style="color:#8dc891">.</span><span class="token plain">ready</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">default</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token punctuation" style="color:#8dc891">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="shutdown">Shutdown<a href="#shutdown" class="hash-link" aria-label="Direct link to Shutdown" title="Direct link to Shutdown"></a></h3> <p>A shutdown function is not yet available in the iOS SDK.</p> <h2 class="anchor anchorWithStickyNavbar_LWe7" id="extending">Extending<a href="#extending" class="hash-link" aria-label="Direct link to Extending" title="Direct link to Extending"></a></h2> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="develop-a-provider">Develop a provider<a href="#develop-a-provider" class="hash-link" aria-label="Direct link to Develop a provider" title="Direct link to Develop a provider"></a></h3> <p>To develop a provider, you need to create a new project and include the OpenFeature SDK as a dependency. You’ll then need to write the provider by implementing the <code>FeatureProvider</code> interface exported by the OpenFeature SDK.</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token keyword" style="color:#c5a5c5">import</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">OpenFeature</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token keyword" style="color:#c5a5c5">final</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">class</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">CustomProvider</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">FeatureProvider</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">var</span><span class="token plain"> hooks</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token plain">any </span><span class="token class-name" style="color:#FAC863">Hook</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token plain"> </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">var</span><span class="token plain"> metadata</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">ProviderMetadata</span><span class="token plain"> </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">CustomMetadata</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">initialize</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">initialContext</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">EvaluationContext</span><span class="token operator" style="color:#d7deea">?</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">async</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// add context-aware provider initialisation</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">onContextSet</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">oldContext</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">EvaluationContext</span><span class="token operator" style="color:#d7deea">?</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> newContext</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">EvaluationContext</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">async</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// add necessary changes on context change</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">getBooleanEvaluation</span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> key</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">String</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> defaultValue</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">Bool</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> context</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">EvaluationContext</span><span class="token operator" style="color:#d7deea">?</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">throws</span><span class="token plain"> </span><span class="token operator" style="color:#d7deea">-></span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">ProviderEvaluation</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">Bool</span><span class="token operator" style="color:#d7deea">></span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// resolve a boolean flag value</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token operator" style="color:#d7deea">...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <blockquote> <p>Built a new provider? <a href="https://github.com/open-feature/openfeature.dev/issues/new?assignees=&labels=provider&projects=&template=document-provider.yaml&title=%5BProvider%5D%3A+" target="_blank" rel="noopener noreferrer">Let us know</a> so we can add it to the docs!</p> </blockquote> <h3 class="anchor anchorWithStickyNavbar_LWe7" id="develop-a-hook">Develop a hook<a href="#develop-a-hook" class="hash-link" aria-label="Direct link to Develop a hook" title="Direct link to Develop a hook"></a></h3> <p>To develop a hook, you need to create a new project and include the OpenFeature SDK as a dependency. Implement your own hook by conforming to the <code>Hook interface</code>. To satisfy the interface, all methods (<code>Before</code>/<code>After</code>/<code>Finally</code>/<code>Error</code>) need to be defined.</p> <div class="language-swift codeBlockContainer_Ckt0 theme-code-block" style="--prism-background-color:#282c34;--prism-color:#ffffff"><div class="codeBlockContent_biex"><pre tabindex="0" class="prism-code language-swift codeBlock_bY9V thin-scrollbar" style="background-color:#282c34;color:#ffffff"><code class="codeBlockLines_e6Vv"><span class="token-line" style="color:#ffffff"><span class="token keyword" style="color:#c5a5c5">class</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">BooleanHook</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">Hook</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">typealias</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token plain"> </span><span class="token operator" style="color:#d7deea">=</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">Bool</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">before</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">ctx</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">HookContext</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> hints</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token class-name" style="color:#FAC863">String</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">Any</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// do something</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">after</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">ctx</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">HookContext</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> details</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">FlagEvaluationDetails</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> hints</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token class-name" style="color:#FAC863">String</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">Any</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// do something</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">error</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">ctx</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">HookContext</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> error</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">Error</span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> hints</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token class-name" style="color:#FAC863">String</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">Any</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// do something</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">func</span><span class="token plain"> </span><span class="token function-definition function" style="color:#79b6f2">finallyAfter</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">(</span><span class="token plain">ctx</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token class-name" style="color:#FAC863">HookContext</span><span class="token operator" style="color:#d7deea"><</span><span class="token class-name" style="color:#FAC863">HookValue</span><span class="token operator" style="color:#d7deea">></span><span class="token punctuation" style="color:#8dc891">,</span><span class="token plain"> hints</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">[</span><span class="token class-name" style="color:#FAC863">String</span><span class="token punctuation" style="color:#8dc891">:</span><span class="token plain"> </span><span class="token keyword" style="color:#c5a5c5">Any</span><span class="token punctuation" style="color:#8dc891">]</span><span class="token punctuation" style="color:#8dc891">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token comment" style="color:#999999">// do something</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"> </span><span class="token punctuation" style="color:#8dc891">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#ffffff"><span class="token plain"></span><span class="token punctuation" style="color:#8dc891">}</span><br></span></code></pre><div class="buttonGroup__atx"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_eSgA" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_y97N"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_LjdS"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> <blockquote> <p>Built a new hook? <a href="https://github.com/open-feature/openfeature.dev/issues/new?assignees=&labels=hook&projects=&template=document-hook.yaml&title=%5BHook%5D%3A+" target="_blank" rel="noopener noreferrer">Let us know</a> so we can add it to the docs!</p> </blockquote></div><footer class="theme-doc-footer 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