--- description: Reference for all Flagship binding evaluation methods, including typed value and details methods for booleans, strings, numbers, and objects. title: Methods image: https://developers.cloudflare.com/og-docs.png --- [Skip to content](#main-content) > Documentation Index > Fetch the complete documentation index at: https://developers.cloudflare.com/flagship/llms.txt > Use this file to discover all available pages before exploring further. # Methods Last updated Aug 24, 2026|Copy as Markdown|[View as Markdown](https://mchen-ai-models-sync.previews.developers.cloudflare.com/flagship/binding/methods/index.md)|[Agent setup](https://mchen-ai-models-sync.previews.developers.cloudflare.com/agent-setup/) The Flagship binding provides the following methods for evaluating feature flags. All methods are asynchronous and return a `Promise`. For known evaluation failures, typed methods return the `defaultValue` you provide. Refer to the [types reference](https://mchen-ai-models-sync.previews.developers.cloudflare.com/flagship/binding/types/) for the definitions of `FlagshipEvaluationContext` and `FlagshipEvaluationDetails`. ## `get()` Returns the raw flag value without type checking. Use this method when the flag type is not known at compile time. If you provide `defaultValue`, `get()` returns that value for known evaluation failures, such as a missing flag. If you omit `defaultValue`, known evaluation failures are thrown. ```ts get(flagKey: string, defaultValue?: unknown, context?: FlagshipEvaluationContext): Promise ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | unknown | No | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const value = await env.FLAGS.get("checkout-flow", "v1", { userId: "user-42", }); ``` ## `getBooleanValue()` Returns the flag value as a `boolean`. ```ts getBooleanValue(flagKey: string, defaultValue: boolean, context?: FlagshipEvaluationContext): Promise ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | boolean | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const enabled = await env.FLAGS.getBooleanValue("dark-mode", false, { userId: "user-42", }); ``` ## `getStringValue()` Returns the flag value as a `string`. ```ts getStringValue(flagKey: string, defaultValue: string, context?: FlagshipEvaluationContext): Promise ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | string | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const variant = await env.FLAGS.getStringValue("checkout-flow", "v1", { userId: "user-42", country: "US", }); ``` ## `getNumberValue()` Returns the flag value as a `number`. ```ts getNumberValue(flagKey: string, defaultValue: number, context?: FlagshipEvaluationContext): Promise ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | number | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const maxRetries = await env.FLAGS.getNumberValue("max-retries", 3, { plan: "enterprise", }); ``` ## `getObjectValue()` Returns the flag value as a typed object. Use the generic parameter `T` to specify the expected shape. ```ts getObjectValue(flagKey: string, defaultValue: T, context?: FlagshipEvaluationContext): Promise ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | T | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts interface ThemeConfig { primaryColor: string; fontSize: number; } const theme = await env.FLAGS.getObjectValue( "theme-config", { primaryColor: "#000", fontSize: 14 }, { userId: "user-42" }, ); ``` ## `getBooleanDetails()` Returns the flag value as a `boolean` with evaluation metadata. ```ts getBooleanDetails(flagKey: string, defaultValue: boolean, context?: FlagshipEvaluationContext): Promise> ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | boolean | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const details = await env.FLAGS.getBooleanDetails("dark-mode", false, { userId: "user-42", }); console.log(details.value); // true console.log(details.reason); // "TARGETING_MATCH" ``` ## `getStringDetails()` Returns the flag value as a `string` with evaluation metadata. ```ts getStringDetails(flagKey: string, defaultValue: string, context?: FlagshipEvaluationContext): Promise> ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | string | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const details = await env.FLAGS.getStringDetails("checkout-flow", "v1", { userId: "user-42", }); console.log(details.value); // "v2" console.log(details.variant); // "new" console.log(details.reason); // "TARGETING_MATCH" ``` ## `getNumberDetails()` Returns the flag value as a `number` with evaluation metadata. ```ts getNumberDetails(flagKey: string, defaultValue: number, context?: FlagshipEvaluationContext): Promise> ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | number | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts const details = await env.FLAGS.getNumberDetails("max-retries", 3, { plan: "enterprise", }); console.log(details.value); // 5 console.log(details.reason); // "TARGETING_MATCH" ``` ## `getObjectDetails()` Returns the flag value as a typed object with evaluation metadata. Use the generic parameter `T` to specify the expected shape. ```ts getObjectDetails(flagKey: string, defaultValue: T, context?: FlagshipEvaluationContext): Promise> ``` | Parameter | Type | Required | Description | | ------------ | ------------------------- | -------- | ------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | T | Yes | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules. | ```ts interface ThemeConfig { primaryColor: string; fontSize: number; } const details = await env.FLAGS.getObjectDetails( "theme-config", { primaryColor: "#000", fontSize: 14 }, { userId: "user-42" }, ); console.log(details.value); // { primaryColor: "#0051FF", fontSize: 16 } console.log(details.variant); // "brand-refresh" ``` ## Error handling Typed evaluation methods return the `defaultValue` you provided for known evaluation failures, such as a missing flag or type mismatch. Unexpected runtime failures can still throw. Use the `*Details` methods to inspect known evaluation failures. ### Type mismatch If you call a typed method on a flag with a different type (for example, `getBooleanValue` on a string flag), the method returns the default value. The `*Details` methods set `errorCode` to `"TYPE_MISMATCH"`. ```ts // Flag "checkout-flow" is a string flag, but you call getBooleanDetails. const details = await env.FLAGS.getBooleanDetails("checkout-flow", false); console.log(details.value); // false (the default value) console.log(details.errorCode); // "TYPE_MISMATCH" ``` ### Evaluation failure If evaluation fails for another reason, the method returns the default value. The `*Details` methods include an `errorCode` such as `"FLAG_NOT_FOUND"`, `"INVALID_CONTEXT"`, `"PARSE_ERROR"`, or `"GENERAL"`. ```ts const details = await env.FLAGS.getStringDetails( "nonexistent-flag", "fallback", ); console.log(details.value); // "fallback" console.log(details.errorCode); // "FLAG_NOT_FOUND" ``` ## Parameters reference The following table summarizes the parameters shared across all evaluation methods. | Parameter | Type | Required | Description | | ------------ | ------------------------- | ---------------- | --------------------------------------------------------------------------------------------- | | flagKey | string | Yes | The key of the flag to evaluate. | | defaultValue | varies | Yes (except get) | The fallback value returned if evaluation fails or the flag is not found. | | context | FlagshipEvaluationContext | No | Key-value attributes for targeting rules (for example, { userId: "user-42", country: "US" }). | Was this helpful? 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