OpenSea provides machine-readable endpoints that help AI agents and LLMs discover and understand the API without reading human-formatted documentation.

llms.txt

The llms.txt file follows the llms.txt standard and provides a plain-text summary.

GET https://opensea.io/llms.txt

Use this as a starting point for any AI agent or LLM that needs to understand what the OpenSea API offers.

OpenAPI Specification

The OpenAPI specification provides a full machine-readable description of every endpoint, including request/response schemas, parameter types, and authentication requirements.

GET https://api.opensea.io/api/v2/openapi.json

This is the recommended entry point for agents that need to programmatically generate API calls, build client libraries, or validate request/response shapes.

When to use which

Endpoint	Format	Best for
`llms.txt`	Plain text	LLM context windows, quick API overview, agent bootstrapping
`openapi.json`	JSON (OpenAPI)	Code generation, SDK building, request validation, detailed schema inspection

Instant API key

Agents can get a free-tier API key instantly with no signup:

POST https://api.opensea.io/api/v2/auth/keys

Returns a key with 60/min read and 5/min write rate limits, valid for 30 days. See Getting Your API Key for details.

Additional resources for agents

Resource	Description
Agent Skill	Install the OpenSea skill in AI agents and coding assistants
OpenSea MCP	Connect AI tools via the Model Context Protocol for natural language access
OpenSea CLI	Command-line interface for scripting and automation