# IP Almanac Docs

> Reverse IP, DNS history and network context for IPs and domains, from one REST API and an MCP server.

- Guides

  - **Get started**
  - [Overview](https://docs.ipalmanac.com/): Who else is on this IP, and since when. Reverse IP, DNS history and network context from one REST API and an MCP server.
  - [Quickstart](https://docs.ipalmanac.com/quickstart): Create an API key, check it, and look up your first IP.
  - [Authentication](https://docs.ipalmanac.com/authentication): Send an API key in the Authorization header. Keys belong to a project and share the workspace's limits.
  - [MCP and AI agents](https://docs.ipalmanac.com/mcp): Connect an AI agent to the MCP server, or point it at the OpenAPI spec and the Markdown guides.

  - **Use cases**
  - [Who else is on an IP](https://docs.ipalmanac.com/use-cases/shared-hosting): List the domains that share an IP, with when each arrived and left.
  - [Investigate a suspicious domain](https://docs.ipalmanac.com/use-cases/suspicious-domain): For a phishing or look-alike domain, check the network behind its addresses and what else shares them.
  - [Map a domain's infrastructure](https://docs.ipalmanac.com/use-cases/infrastructure): Follow where a popular domain pointed, the networks it moved through, and what those networks route.

  - **Using the API**
  - [Read a response](https://docs.ipalmanac.com/reading-answers): What null, empty lists, stale states and the dates in a response mean, and what they don't.
  - [Data and coverage](https://docs.ipalmanac.com/data-and-coverage): Where the data comes from, where it is strong and thin, and how to tell how fresh an answer is.
  - [Pagination](https://docs.ipalmanac.com/pagination): Long lists come in pages. Pass next_cursor back as cursor until it is null.
  - [Errors](https://docs.ipalmanac.com/errors): The error codes the API returns, what each means, and whether to retry.
  - [Rate limits and quotas](https://docs.ipalmanac.com/rate-limits): Each workspace has a monthly quota and a per-minute rate, set by its plan. Response headers show where you stand.
- API reference
  - [Overview](https://docs.ipalmanac.com/api-reference): The REST API's operations, generated from its OpenAPI spec.
  - [Look up a public IP](https://docs.ipalmanac.com/api-reference/lookup-ip): What was observed about one public IP: its mapped ASN, provider ranges (cloud, hosting, CDN), PTR name and the domains seen resolving to it.
  - [List the domains seen on an IP](https://docs.ipalmanac.com/api-reference/ip-domains): Reverse IP: the domains observed resolving to an IP (who else is on it), one item per answer interval, oldest first.
  - [Show a domain's DNS history](https://docs.ipalmanac.com/api-reference/domain-history): A domain's current A/AAAA state, with staleness, and its answer intervals, oldest first.
  - [Show the networks a domain moved through](https://docs.ipalmanac.com/api-reference/domain-hosting): Hosting history: the networks a domain's A/AAAA answers moved through, one run per stretch on one network (routing ASN and cloud, hosting or CDN provider), oldest first, with when it was first and last seen there and when it left.
  - [Look up an ASN](https://docs.ipalmanac.com/api-reference/lookup-asn): One network: the IP ranges the IPtoASN mapping assigns to the ASN, its name and registry country, the published cloud, hosting and CDN ranges inside them, and how many IPs and domains were observed there.
  - [Check an API key](https://docs.ipalmanac.com/api-reference/ping): Check that your API key works.
  - [Check service health](https://docs.ipalmanac.com/api-reference/health): Whether the service is up, and the data release it serves.