> ## Documentation Index > Fetch the complete documentation index at: https://docs.traffical.io/llms.txt > Use this file to discover all available pages before exploring further. # POST /v1/resolve > Server-side parameter resolution for SDKs in `evaluationMode: "server"`. Resolves parameters for a given context server-side. Use this when an SDK can't cache a full config bundle, or when you want every resolution to use the freshest possible state. The React Native SDK uses this endpoint by default. Most server and web use cases should prefer the bundle-based path (`GET /v1/config/:projectId` + local resolution) — it's faster, works offline, and scales further. ## Request ``` POST /v1/resolve ``` ### Headers | Header | Required | Description | | --------------- | ------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------- | | `Authorization` | Yes | `Bearer traffical_sk_...` (requires `sdk:read` scope) | | `Content-Type` | Yes | `application/json` | | `X-Project-Id` | Only for org-scoped keys | Selects the project when the key is not pinned to one. For project-pinned keys the header is unnecessary; a mismatching value is rejected with `403`. | | `X-Env` | No | Environment name. Defaults to `production`; the body `env` field takes precedence. | The project is identified by the API key, not the request body. Keys created for a specific project need no extra headers. ### Body ```json theme={null} { "context": { "userId": "user_789", "locale": "en-US", "plan": "pro" }, "parameters": [ "checkout.button.color", "checkout.show_trust_badges" ] } ``` | Field | Type | Required | Description | | ------------ | ---------- | -------- | ------------------------------------------------------------------------------------------------------------- | | `context` | `object` | Yes | Must include the project's unit key (for example, `userId`). Other fields are available to policy conditions. | | `env` | `string` | No | Environment to resolve against. Defaults to the `X-Env` header, then `production`. | | `parameters` | `string[]` | No | Parameter keys to resolve. Omit to resolve all parameters in the project. | There is no `defaults` field: fallback values come from each parameter's configured default in the config bundle (with environment overrides applied). Parameters not covered by any matching policy resolve to those defaults. ## Response ### 200 OK ```json theme={null} { "decisionId": "dec_abc123", "assignments": { "checkout.button.color": "#22C55E", "checkout.show_trust_badges": true }, "metadata": { "timestamp": "2026-05-21T10:30:00Z", "unitKeyValue": "user_789", "layers": [ { "layerId": "layer_checkout", "bucket": 742, "policyId": "policy_color_test", "allocationId": "alloc_b", "allocationName": "treatment" } ], "configVersion": "2026-05-21T09:58:11Z" }, "stateVersion": "2026-05-21T09:58:11Z", "suggestedRefreshMs": 60000 } ``` | Field | Type | Description | | ------------------------ | ---------- | ----------------------------------------------------------------------------------------------------- | | `decisionId` | `string` | Unique ID for this resolution. Use it on subsequent track events for attribution. | | `assignments` | `object` | Resolved parameter values keyed by parameter key. | | `metadata.timestamp` | `string` | ISO 8601 timestamp of the decision. | | `metadata.unitKeyValue` | `string` | The unit key value used for bucket computation. | | `metadata.layers` | `object[]` | Per-layer resolution info (see below). | | `metadata.configVersion` | `string` | `version` of the config bundle this resolution used — mirrors the top-level `stateVersion`. | | `stateVersion` | `string` | `version` of the config bundle this resolution used. | | `suggestedRefreshMs` | `number` | How long the result stays fresh — re-resolve after this many milliseconds (currently always `60000`). | When a matched adaptive policy is configured to log context fields, the response also includes `metadata.filteredContext` containing just those fields. Each entry in `metadata.layers` describes one layer's resolution: | Field | Type | Description | | ----------------- | --------- | ----------------------------------------------------------------------------------------------------------------------------------------------------- | | `layerId` | `string` | Layer ID | | `bucket` | `number` | Bucket computed for this layer (`0` to `bucketCount − 1`) | | `policyId` | `string` | Policy that matched, if any | | `allocationId` | `string` | Selected allocation ID, if a policy matched | | `allocationName` | `string` | Selected allocation name (for example, `control`, `treatment`) | | `attributionOnly` | `boolean` | Present and `true` when the layer was resolved for attribution only — none of its parameters were requested. Skip exposure tracking for these layers. | Every successful resolution automatically records a decision event — you don't need to send one through `POST /v1/events`. ### 400 Bad request ```json theme={null} { "error": { "code": "BAD_REQUEST", "message": "context is required" } } ``` Also returned for an invalid JSON body, and for org-scoped keys that omit the `X-Project-Id` header. ### 401 Unauthorized ```json theme={null} { "error": { "code": "UNAUTHORIZED", "message": "Invalid API key" } } ``` ### 403 Forbidden Returned when the key lacks the `sdk:read` scope, or when an `X-Org-Id` or `X-Project-Id` header doesn't match the key: ```json theme={null} { "error": { "code": "FORBIDDEN", "message": "SDK read scope required" } } ``` ### 404 Not found ```json theme={null} { "error": { "code": "NOT_FOUND", "message": "Bundle not found for proj_marketplace/production" } } ``` ### 503 Service unavailable The config store is temporarily unavailable. Fall back to local resolution or defaults and retry shortly. ```json theme={null} { "error": { "code": "SERVICE_UNAVAILABLE", "message": "Config store temporarily unavailable, retry shortly" } } ``` ## When to use this * Mobile clients where caching a full bundle isn't reasonable (very limited memory, or very rare resolutions). * Server-to-server systems where you want fresh state without managing bundle refresh in your own code. * Per-entity adaptive policies where bundle-mode freshness isn't sufficient — though `POST /v1/decide/:policyId` is usually the right answer for that specific case. For everything else, prefer `GET /v1/config/:projectId` and resolve locally.