# Subdomain API (subdomain.app)

Returns known subdomains of any domain from a historic index, served as JSON through an API and an MCP server.

- Atlas card: https://inite.ai/en/atlas/subdomain.app
- Site: https://subdomain.app
- For: Security researchers, pentesters and bug bounty hunters mapping a domain's attack surface, plus IT and SEO teams tracking its footprint.
- Use 0/100 · alive 100/100

## Used for

- map a target's attack surface during pentests
- find forgotten subdomains during bug bounty research
- track how a domain's subdomains change over time

## Price

Not read yet.

## For developers

- OpenAPI: https://api.subdomain.app/openapi.json (1 paths)
- API docs: https://api.subdomain.app
- MCP server: app.subdomain/subdomains (namespace; open on 2026-10-14, 2 tools)
- Read 2026-10-14

## Your data

- Certifications stated: none
- Read 2026-10-14

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Source: INITE Atlas, https://inite.ai/en/atlas/subdomain.app. JSON: https://inite.ai/api/atlas/subdomain.app. MCP: https://inite.ai/api/mcp (atlas_lookup).