osmAPI Chat API
The Chat API from osmAPI — 1 operation(s) for chat.
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OpenAPI Specification
openapi: 3.2.0
info:
title: osmAPI Anthropic Messages Chat API
description: Anthropic-compatible messages endpoint routed through osmAPI's unified AI gateway. Supports the native Anthropic message format including system prompts, extended thinking, tool use, and streaming.
version: 1.0.0
contact:
name: osmAPI
url: https://www.osmapi.com/
servers:
- url: https://api.osmapi.com/v1
description: Production
security:
- bearerAuth: []
tags:
- name: Chat
paths:
/chat/completions:
post:
operationId: createChatCompletion
summary: Create chat completion
description: Sends a chat completion request to the specified model through osmAPI's smart routing system. Compatible with the OpenAI chat completions format.
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/ChatCompletionRequest'
responses:
'200':
description: Successful completion response
content:
application/json:
schema:
$ref: '#/components/schemas/ChatCompletionResponse'
'429':
description: Rate limit exceeded
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
'500':
description: Server error
content:
application/json:
schema:
$ref: '#/components/schemas/ErrorResponse'
tags:
- Chat
components:
schemas:
Metadata:
type: object
properties:
requested_model:
type: string
used_model:
type: string
used_provider:
type: string
ErrorResponse:
type: object
properties:
error:
type: object
properties:
message:
type: string
type:
type: string
code:
type: string
ChatCompletionResponse:
type: object
properties:
id:
type: string
object:
type: string
created:
type: integer
model:
type: string
choices:
type: array
items:
$ref: '#/components/schemas/Choice'
usage:
$ref: '#/components/schemas/Usage'
metadata:
$ref: '#/components/schemas/Metadata'
Usage:
type: object
properties:
prompt_tokens:
type: integer
completion_tokens:
type: integer
total_tokens:
type: integer
reasoning_tokens:
type: integer
cost_usd_total:
type: number
cost_usd_input:
type: number
cost_usd_output:
type: number
Message:
type: object
required:
- role
- content
properties:
role:
type: string
enum:
- system
- user
- assistant
- tool
- function
content:
oneOf:
- type: string
- type: array
items:
type: object
name:
type: string
tool_call_id:
type: string
tool_calls:
type: array
items:
type: object
Choice:
type: object
properties:
index:
type: integer
message:
type: object
properties:
role:
type: string
content:
type: string
reasoning:
type: string
tool_calls:
type: array
items:
type: object
images:
type: array
items:
type: string
finish_reason:
type: string
ChatCompletionRequest:
type: object
required:
- model
- messages
properties:
model:
type: string
description: The AI model identifier or "auto" for smart routing
examples:
- gpt-4o
- auto
- openai/gpt-4o
messages:
type: array
items:
$ref: '#/components/schemas/Message'
description: Conversation history with role-content pairs
temperature:
type: number
nullable: true
description: Controls response randomness (0-2)
max_tokens:
type: integer
nullable: true
description: Maximum number of tokens to generate
top_p:
type: number
nullable: true
description: Nucleus sampling parameter
frequency_penalty:
type: number
nullable: true
description: Reduces token repetition
presence_penalty:
type: number
nullable: true
description: Encourages new topics
stream:
type: boolean
default: false
description: Enable streaming responses
response_format:
type: object
description: Specifies output structure (JSON schema support)
tools:
type: array
items:
type: object
description: Available functions for model invocation
tool_choice:
oneOf:
- type: string
- type: object
description: Tool selection strategy (required, none, auto)
reasoning_effort:
type: string
nullable: true
enum:
- minimal
- low
- medium
- high
description: Reasoning intensity for supported models
free_models_only:
type: boolean
description: Routes only to cost-free models
no_reasoning:
type: boolean
description: Excludes reasoning models from routing
web_search:
type: boolean
description: Enables real-time web search grounding
plugins:
type: array
items:
type: string
description: Extended functionality plugins (e.g., response-healing)
securitySchemes:
bearerAuth:
type: http
scheme: bearer
description: Bearer token using osmAPI key (osmint_XXXXXXXXXXXXXXXX)