> ## Documentation Index > Fetch the complete documentation index at: https://www.voiceflow.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Execute function > Runs the saved draft of a function once with the inputs in the body, without compiling the agent or starting a conversation. The run stops at the function's timeout or 18 seconds, whichever is shorter, and nothing is saved. ## OpenAPI ````yaml /specs-prettified/realtime/openapi.stable.json post /v1/stable/function/{functionID}/execute openapi: 3.0.0 info: title: Realtime description: Realtime gateway API service version: 1.0.0 contact: {} servers: - url: https://realtime-api.voiceflow.com security: [] tags: [] paths: /v1/stable/function/{functionID}/execute: post: tags: - Function summary: Execute function description: Runs the saved draft of a function once with the inputs in the body, without compiling the agent or starting a conversation. The run stops at the function's timeout or 18 seconds, whichever is shorter, and nothing is saved. operationId: StableFunctionController_execute parameters: - name: functionID required: true in: path schema: type: string x-vf-doc: description: The ID of the function to execute. description: The ID of the function to execute. - name: projectID required: true in: query schema: type: string description: The ID of the project to operate on. - name: environmentAlias required: true in: query schema: type: string description: The alias of the environment to operate on (e.g. `main`). requestBody: required: true content: application/json: schema: $ref: "#/components/schemas/StableFunctionExecuteRequest" responses: "200": description: Returns the function's output variables, the exit path it chose, and the traces it emitted, with success, latencyMs, and error fields. content: application/json: schema: $ref: "#/components/schemas/StableFunctionExecuteResponse" x-vf-doc: description: Returns the function's output variables, the exit path it chose, and the traces it emitted, with success, latencyMs, and error fields. security: - token: [] components: schemas: StableFunctionExecuteRequest: type: object properties: inputs: default: {} description: A value for each of the function's input variables, keyed by input name. Every declared input needs a value, and a name the function does not declare is refused. List them with get_schema. type: object additionalProperties: $ref: "#/components/schemas/ExecuteInputString" additionalProperties: false ExecuteInputString: type: string description: "A value sent to a tool for one run, never stored. Plain text. {secret_name} inserts a project secret: the server fills in the value this environment would use in a conversation, and the value reads [secret] wherever it appears in the result. Brace text is a token when the text between the braces has no space at either end and holds only letters, digits, underscores, inner spaces, ., [, ], $ or -. A token that names no project secret, such as {customer_id} or {var name}, is refused before the tool runs, because a single run has no conversation to read a variable from: pass the value itself. Any other brace text is sent as written, so code, JSON and GraphQL such as query { user { id } } run as they are. Compact brace text such as {id} still reads as a token: write { id } to send it as text. A secret whose name is not letters, digits and underscores cannot be referenced. A {secret_name} token is filled in only in a top-level string value of inputs. Inside a nested object or array it is sent as written, and no secret is filled in." StableFunctionExecuteResponse: type: object properties: success: type: boolean description: Whether the tool ran and reported no error. latencyMs: type: number description: How long the run took, in milliseconds, measured by this API around the call. error: nullable: true description: Why the run failed when `success` is false, otherwise null. Secret values read `[secret]`. type: string truncated: type: boolean description: Whether a returned payload was over 64 KB and was cut to its first 64 KB of JSON text, which then arrives as a string. output: nullable: true description: What the function returned, on failure too. Null only when general-runtime did not answer in time. allOf: - $ref: "#/components/schemas/StableFunctionExecuteOutput" required: - success - latencyMs - error - truncated - output StableFunctionExecuteOutput: type: object properties: outputVars: type: object additionalProperties: {} description: The output variables the function returned, keyed by name. At runtime only string, number and boolean values reach a variable. path: nullable: true description: "The exit path the function chose with `next: { path }`, or null when it chose none." type: string traces: type: array items: $ref: "#/components/schemas/StableFunctionExecuteTrace" description: The traces the function emitted, in order. A failed run may carry a `debug` trace that says why, but not always. required: - outputVars - path - traces StableFunctionExecuteTrace: type: object properties: type: type: string description: The trace type, such as `text`, `speak`, `choice`, `cardV2` or `debug`. payload: description: The trace payload as the function emitted it. Secret values read `[secret]`. required: - type - payload securitySchemes: token: scheme: bearer bearerFormat: JWT type: http description: Voiceflow bearer token ````