OpenAPI Documentation

Rill automatically generates an OpenAPI specification for your project that combines built-in APIs with your custom API definitions. You can add request and response schemas to your APIs for better documentation and typed client generation.

Adding an OpenAPI spec to your API

Add an openapi block to your API definition with request_schema and response_schema:

type: api

sql: |
  SELECT publisher, COUNT(*) as total_records
  FROM ad_bids
  WHERE domain = '{{ .args.domain }}'
  {{ if hasKey .args "publisher" }}
    AND publisher = '{{ .args.publisher }}'
  {{ end }}
  ORDER BY total_records DESC
  LIMIT {{ default 25 .args.limit }}
  OFFSET {{ default 0 .args.offset }}

openapi:
  summary: Get ad bid statistics by publisher, filtered by domain

  request_schema:
    type: object
    required:
      - domain
    properties:
      domain:
        type: string
        description: Domain to filter results by
      publisher:
        type: string
        description: Optional publisher filter
      limit:
        type: integer
        description: Number of results to return (default 25)
      offset:
        type: integer
        description: Offset for pagination (default 0)

  response_schema:
    type: object
    properties:
      publisher:
        type: string
        description: Publisher name
      total_records:
        type: integer
        description: Total number of ad bid records

OpenAPI fields

Field	Description
openapi.summary	Short description of what the API does (appears in OpenAPI docs)
openapi.request_schema	JSON Schema describing the request parameters
openapi.response_schema	JSON Schema describing a single row in the response array

Schemas follow the JSON Schema format. You can use type, required, properties, description, and other standard JSON Schema keywords.

Downloading the OpenAPI spec

Locally

curl http://localhost:9009/v1/instances/default/api/openapi -o openapi.json

From Rill Cloud

curl "https://api.rilldata.com/v1/organizations/<org>/projects/<project>/runtime/api/openapi" \
  -H "Authorization: Bearer <token>" \
  -o openapi.json

The generated spec includes all your custom APIs with their schemas, plus Rill's built-in API endpoints.

Generating typed clients

Use the downloaded OpenAPI spec with any code generation tool to create typed clients for your language:

JavaScript/TypeScript (using openapi-typescript):

npx openapi-typescript openapi.json -o ./src/api-types.ts

Python (using openapi-python-client):

openapi-python-client generate --path openapi.json

Go (using oapi-codegen):

oapi-codegen -package api openapi.json > api/client.go

Full example

Here's a complete API with OpenAPI documentation, templating, and security:

type: api

metrics_sql: |
  SELECT publisher, domain, total_records, avg_bid_price
  FROM ad_bids_metrics
  WHERE domain = '{{ .args.domain }}'
  {{ if hasKey .args "publisher" }}
    AND publisher = '{{ .args.publisher }}'
  {{ end }}
  ORDER BY total_records DESC
  LIMIT {{ default 25 .args.limit }}
  OFFSET {{ default 0 .args.offset }}

security:
  access: true

openapi:
  summary: Query ad bid metrics by domain with optional publisher filter

  request_schema:
    type: object
    required:
      - domain
    properties:
      domain:
        type: string
        description: Domain to filter metrics by (e.g., "google.com")
      publisher:
        type: string
        description: Optional publisher to filter by (e.g., "Facebook")
      limit:
        type: integer
        description: Max results to return (default 25, max 1000)
      offset:
        type: integer
        description: Pagination offset (default 0)

  response_schema:
    type: object
    properties:
      publisher:
        type: string
        description: Publisher name
      domain:
        type: string
        description: Domain name
      total_records:
        type: integer
        description: Total number of records
      avg_bid_price:
        type: number
        description: Average bid price in USD