dottxt Chat API
OpenAI-compatible chat completions with structured output.
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OpenAPI Specification
openapi: 3.2.0
info:
title: dottxt Platform Chat API
version: v1
description: OpenAI-compatible structured-output API from dottxt (.txt), the makers of Outlines. The API guarantees 100% schema-compliant model output by construction using constrained decoding. It follows the OpenAI Chat Completions request/response shape, so existing OpenAI SDKs work by changing the base URL and API key. Structured output is requested with the `response_format` parameter (JSON Schema), and results can be streamed as token deltas (SSE) or field-by-field as RFC 6902 JSON Patch events. This specification is a faithful transcription of the public API reference at https://docs.dottxt.ai/api/overview ; it is not published by dottxt.
contact:
name: dottxt
url: https://dottxt.ai/
email: contact@dottxt.co
x-provenance:
generated: '2026-07-18'
method: generated
source: https://docs.dottxt.ai/api/overview.md
servers:
- url: https://api.dottxt.ai/v1
description: dottxt production API
security:
- bearerAuth: []
tags:
- name: Chat
description: OpenAI-compatible chat completions with structured output.
paths:
/chat/completions:
post:
operationId: createChatCompletion
tags:
- Chat
summary: Create Chat Completion
description: Generate a model response from a message array, with support for token streaming, JSON Patch streaming, structured output via `response_format`, and tool calling. OpenAI Chat Completions compatible.
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/CreateChatCompletionRequest'
responses:
'200':
description: Chat completion (or a stream of chunks when `stream` is set).
content:
application/json:
schema:
$ref: '#/components/schemas/ChatCompletion'
'400':
description: Invalid request format.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'401':
description: Missing or invalid API key.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'402':
description: Insufficient credits.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'403':
description: No access to the requested model.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'404':
description: Model not found.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'429':
description: Rate limit exceeded.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
'500':
description: Server error.
content:
application/json:
schema:
$ref: '#/components/schemas/OpenAIErrorResponse'
components:
schemas:
ChatCompletionChoice:
type: object
properties:
index:
type: integer
finish_reason:
type: string
example: stop
message:
$ref: '#/components/schemas/ChatMessage'
CreateChatCompletionRequest:
type: object
required:
- model
- messages
properties:
model:
type: string
description: Model ID to use.
example: openai/gpt-oss-20b
messages:
type: array
description: The conversation so far, as an array of role/content messages.
items:
$ref: '#/components/schemas/ChatMessage'
response_format:
$ref: '#/components/schemas/ResponseFormat'
stream:
description: '`false` (default) returns one JSON response; `true` streams token deltas as SSE; `"patch"` streams RFC 6902 JSON Patch operations per field (NDJSON by default, or SSE with `Accept: text/event-stream`).'
oneOf:
- type: boolean
- type: string
enum:
- patch
temperature:
type: number
minimum: 0
maximum: 2
max_tokens:
type: integer
format: int32
top_p:
type: number
frequency_penalty:
type: number
minimum: -2
maximum: 2
presence_penalty:
type: number
minimum: -2
maximum: 2
seed:
type: integer
format: int64
stop:
type: array
maxItems: 4
items:
type: string
n:
type: integer
format: int32
tools:
type: array
description: Functions the model may call.
items:
type: object
tool_choice:
description: Controls tool invocation.
user:
type: string
description: End-user identifier.
ChatMessage:
type: object
required:
- role
- content
properties:
role:
type: string
enum:
- system
- user
- assistant
- tool
content:
type: string
OpenAIErrorResponse:
type: object
required:
- error
properties:
error:
type: object
properties:
code:
type: string
message:
type: string
type:
type: string
param:
type: string
ResponseFormat:
type: object
description: Structured-output constraint. Use `json_schema` for schema-guaranteed output.
properties:
type:
type: string
enum:
- text
- json_object
- json_schema
json_schema:
type: object
properties:
name:
type: string
schema:
type: object
description: A JSON Schema document the output is guaranteed to satisfy.
Usage:
type: object
properties:
prompt_tokens:
type: integer
completion_tokens:
type: integer
total_tokens:
type: integer
ChatCompletion:
type: object
properties:
id:
type: string
object:
type: string
example: chat.completion
created:
type: integer
format: int64
model:
type: string
choices:
type: array
items:
$ref: '#/components/schemas/ChatCompletionChoice'
usage:
$ref: '#/components/schemas/Usage'
securitySchemes:
bearerAuth:
type: http
scheme: bearer
description: 'API key passed as a bearer token: `Authorization: Bearer $DOTTXT_API_KEY`. Keys use the prefix `sk-dottxt-`.'