Subdomain API
Find known subdomains of a domain. Passive data; may include historic entries. List or count.
| Endpoint | https://api.subdomain.app/mcp (streamable-http) |
|---|---|
| Registry version | 1.0.1 |
| Now | 2 tools · grade A (94) · pin ts_5f921e4e93d60425abcce13f6d1839cf · protocol 2025-06-18 |
| First / last listed | 2026-10-29 01:33 UTC / 2026-10-29 01:33 UTC |
| Grade over time | 2026-10-29: A (94), 2 tools |
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Tools: find_subdomains count_subdomains
find_subdomains | List known subdomains (hostnames) of a root domain. Data is passive (not active scanning): results are historic observations and may include subdomains that no longer resolve or are no longer live. Results are a point-in-time snapshot that changes over time as new subdomains are observed — re-query rather than caching the result. Use for attack-surface mapping, security recon, asset inventory, or params: domain*, limit |
count_subdomains | Return only the total number of distinct subdomains known for a domain — no list. Cheap and low-token. Use when the user asks "how many subdomains" or you only need the size of the attack surface. Count includes historic subdomains that may no longer be live. It is a point-in-time figure that changes over time, so treat it as current-as-of-query, not a fixed value. params: domain* |
Entries describe changes in tool definitions. They are not statements about a server, its quality or its author. The grade measures how the tool definitions fit model providers (token cost, schema compatibility, confusable names) as scored by the ToolFit engine at the time of the listing. JSON: append .json. Opt-out: how or hello@youraitools.co.