> ## Documentation Index > Fetch the complete documentation index at: https://docs.fastrun.si/llms.txt > Use this file to discover all available pages before exploring further. # Create a completion > Continues a raw text prompt with no chat template applied. Compatible with OpenAI's legacy Completions API. Use chat completions unless you build the prompt format yourself. ## OpenAPI ````yaml /openapi.yaml post /completions openapi: 3.1.0 info: title: fastrun API version: '1.0' description: >- OpenAI-compatible inference API. Point any OpenAI SDK at https://api.fastrun.si/v1 and send a fastrun API key as a bearer token. servers: - url: https://api.fastrun.si/v1 security: - bearerAuth: [] tags: - name: Chat description: Conversations with chat messages. - name: Completions description: Raw text continuation. - name: Models description: The models you can use. paths: /completions: post: tags: - Completions summary: Create a completion description: >- Continues a raw text prompt with no chat template applied. Compatible with OpenAI's legacy Completions API. Use chat completions unless you build the prompt format yourself. operationId: createCompletion requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CompletionRequest' example: model: google/gemma-4-31b-it prompt: The three primary colors are max_tokens: 32 responses: '200': description: >- The completion. With `stream: true` the body is a `text/event-stream` of completion events ending with `data: [DONE]`. content: application/json: schema: $ref: '#/components/schemas/Completion' '400': $ref: '#/components/responses/BadRequest' '401': $ref: '#/components/responses/Unauthorized' '429': $ref: '#/components/responses/TooManyRequests' '502': $ref: '#/components/responses/BadGateway' '503': $ref: '#/components/responses/Unavailable' components: schemas: CompletionRequest: type: object required: - model - prompt properties: model: type: string examples: - google/gemma-4-31b-it prompt: description: The text to continue. oneOf: - type: string - type: array items: type: string stream: type: boolean default: false stream_options: type: object properties: include_usage: type: boolean default: false max_tokens: type: integer minimum: 1 maximum: 16384 default: 16 description: Maximum number of tokens to generate. temperature: type: number minimum: 0 maximum: 2 top_p: type: number minimum: 0 maximum: 1 top_k: type: integer minimum: 0 maximum: 1000 stop: oneOf: - type: string - type: array maxItems: 4 items: type: string seed: type: integer logprobs: type: integer minimum: 0 maximum: 20 description: >- Return the log probabilities of this many most likely tokens at each position. Completion: type: object properties: id: type: string object: type: string enum: - text_completion created: type: integer model: type: string choices: type: array items: type: object properties: index: type: integer text: type: string finish_reason: type: string enum: - stop - length usage: $ref: '#/components/schemas/Usage' Usage: type: object properties: prompt_tokens: type: integer description: Input tokens, including cached ones. completion_tokens: type: integer description: Generated tokens, including reasoning tokens. total_tokens: type: integer prompt_tokens_details: type: object properties: cached_tokens: type: integer description: >- Input tokens served from the prompt cache. See [Prompt caching](/guides/prompt-caching). Error: type: object required: - error properties: error: type: object required: - message - type - code properties: message: type: string description: What went wrong, for people. type: type: string description: Error category, for code. enum: - invalid_request_error - authentication_error - rate_limit_error - upstream_error - unavailable code: type: integer description: The HTTP status. responses: BadRequest: description: >- The request is malformed: the body is not a JSON object, `model` is missing, or the model rejected a parameter (for example, a prompt longer than the context window). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: model is required type: invalid_request_error code: 400 Unauthorized: description: >- The API key is missing, unknown or revoked, or the account has not been approved yet. content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: invalid or missing API key type: authentication_error code: 401 TooManyRequests: description: >- Every GPU serving the model is busy. Retry after the number of seconds in `Retry-After`. headers: Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: all backends for this model are at capacity type: rate_limit_error code: 429 BadGateway: description: The GPU servers failed to answer. Safe to retry. headers: Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: all backends refused the request type: upstream_error code: 502 Unavailable: description: >- Temporarily unavailable: no GPU server for the model is up, or API keys cannot be checked right now. Retry after the number of seconds in `Retry-After`. headers: Retry-After: $ref: '#/components/headers/RetryAfter' content: application/json: schema: $ref: '#/components/schemas/Error' example: error: message: no backend is available for this model type: unavailable code: 503 headers: RetryAfter: description: Seconds to wait before retrying. schema: type: integer minimum: 1 securitySchemes: bearerAuth: type: http scheme: bearer description: A key from https://fastrun.si/dashboard/keys (starts with `fr_`). ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.