Fastly API - Unofficial OpenAPI Specification

This repository contains an unofficial OpenAPI 3.0 specification for the Fastly API. It was created by reverse engineering the publicly available API documentation.

Disclaimer

This is an unofficial specification and is not endorsed, supported, or guaranteed by Fastly. It may be incomplete or contain inaccuracies. The specification is provided "as is" without warranty of any kind.

Features

• Comprehensive OpenAPI 3.0 schema for Fastly's CDN API
• Detailed endpoint descriptions and examples
• Schema definitions for request and response objects
• Support for all major Fastly API functionality:
  • Service management
  • Domain configuration
  • Backend management
  • VCL manipulation
  • Cache controls
  • Purging operations
  • Edge dictionaries
  • WAF security
  • Logging endpoints
  • Stats and metrics
  • Compute@Edge

Specifications

This repository contains two OpenAPI specifications:

fastly-openapi.yaml

The complete specification of the Fastly API, containing all endpoints, parameters, and schemas. This is useful for comprehensive API documentation and client generation.

fastly-openapi-mcp.yaml

A streamlined subset of the API specifically optimized for AI agent interaction. This specification:

• Contains only the most frequently used endpoints for common Fastly tasks
• Focuses on the core operations needed for day-to-day management
• Maintains detailed descriptions and examples optimized for AI comprehension
• Prioritizes endpoints that are most useful in conversational interfaces
• Follows a task-based organization matching common user workflows

The MCP version is ideal for integration with AI assistants and tools that need to interact with Fastly through natural language interfaces.

Usage

Viewing Documentation

You can generate interactive documentation from these specifications using tools like:

• Redoc
• Swagger UI

Examples:

# For the complete API
npx @redocly/cli preview-docs fastly-openapi.yaml

# For the AI-optimized subset
npx @redocly/cli preview-docs fastly-openapi-mcp.yaml

Validation

To validate the specifications:

# For the complete API
npx @stoplight/spectral-cli lint fastly-openapi.yaml

# For the AI-optimized subset
npx @stoplight/spectral-cli lint fastly-openapi-mcp.yaml

Code Generation

These specifications can be used with OpenAPI code generators to create client libraries in various programming languages:

# For the complete API
npx @openapitools/openapi-generator-cli generate -i fastly-openapi.yaml -g javascript -o ./client

# For the AI-optimized subset
npx @openapitools/openapi-generator-cli generate -i fastly-openapi-mcp.yaml -g javascript -o ./client-mcp

Agent Readiness

Both specifications are designed to be "agent-ready" - optimized for use with AI agents and tools. They follow best practices for machine readability:

• Detailed operation descriptions
• Consistent naming patterns
• Complete schema documentation
• Examples for all operations

The MCP version takes agent-readiness even further with:

• Curated selection of high-value endpoints for common tasks
• Task-oriented organization aligned with user intents
• Enhanced descriptions focused on conversational contexts
• Removal of specialized endpoints that rarely appear in everyday usage
• Optimized for reduced token consumption in AI contexts

For specific use cases for the MCP specification, see subset.md which outlines common conversational tasks and the corresponding API workflows.

Resources

• Fastly API Documentation
• OpenAPI Specification
• Spectral - OpenAPI Linter