OpenAI

OpenAI Completions API

Given a prompt, the model will return one or more predicted completions, and can also return the probabilities of alternative tokens at each position.

Documentation GitHub OpenAPI

Business capability

Model Inference AE-110.10

Operations 1

Each operation below carries the questions people ask an LLM about it and the instructions they give an agent to run it. Generated by API Evangelist overlay

POST /completions Generate a text completion for a prompt · Create completion #

Ask an LLM

“How do I get a model to continue a piece of text with the legacy completions endpoint?”

“Can I stream completion tokens back as they're generated?”

Tell an agent

Complete the prompt {prompt} using {model}.

Complete {prompt} with {model}, at most {max_tokens} tokens and temperature {temperature}.

Documentation

https://platform.openai.com/docs/assistants/overview

https://platform.openai.com/docs/api-reference/assistants

https://platform.openai.com/docs/guides/text-to-speech

https://platform.openai.com/docs/api-reference/audio

https://platform.openai.com/docs/guides/speech-to-text

https://developers.openai.com/api/docs/guides/audio/

https://developers.openai.com/api/docs/guides/voice-agents/

https://platform.openai.com/docs/api-reference/chat

https://platform.openai.com/docs/guides/embeddings

https://platform.openai.com/docs/api-reference/embeddings

https://platform.openai.com/docs/api-reference/files

https://platform.openai.com/docs/guides/fine-tuning

https://platform.openai.com/docs/api-reference/fine-tuning

https://platform.openai.com/docs/guides/images

https://platform.openai.com/docs/api-reference/images

https://platform.openai.com/docs/guides/image-generation

https://platform.openai.com/docs/guides/images-vision

https://platform.openai.com/docs/models

https://platform.openai.com/docs/api-reference/models

https://platform.openai.com/docs/assistants/how-it-works/managing-threads-and-messages

https://platform.openai.com/docs/api-reference/threads

https://platform.openai.com/docs/api-reference/completions

Specifications

https://artifacts.apis.io/openai/openapi/openai-completions-api-openapi.yml

Schemas & Data

https://artifacts.apis.io/openai/json-schema/openai-chat-completion-schema.json

https://artifacts.apis.io/openai/json-schema/openai-embedding-schema.json

Other Resources

https://artifacts.apis.io/openai/json-ld/openai-context.jsonld

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this

find_apisBrowse and filter every API in the catalog.
get_api_artifactsOne API's artifacts, grouped by type.
get_openapiThe primary OpenAPI for this API.
find_similar_apisAPIs that look like this one.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This API

curl "https://apis.io/api/v1/apis/openai:openai-completions-api"

All apis

curl "https://apis.io/api/v1/apis?limit=25"

Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

openapi: 3.2.0
info:
  title: Openai Completions API
  version: 2.3.0
  contact:
    name: OpenAI Support
    url: https://help.openai.com/
  license:
    name: MIT
    identifier: MIT
  termsOfService: https://openai.com/policies/terms-of-use
  description: 'Operations tagged Completions across 2 of this provider''s published API definitions: openai-openapi-master-2026-09-23.yml, openai-openapi-master-2026-10-12.yml. Each path carries the servers of the definition it was published in.'
servers:
- url: https://api.openai.com/v1
security:
- ApiKeyAuth: []
tags:


# --- truncated at 32 KB (46 KB total) ---
# Full source: https://artifacts.apis.io/openai/openapi/openai-completions-api-openapi.yml