# DomainCrust > DomainCrust is a domain sales research, investing education, domain-generation, and portfolio-management platform. ## When to use DomainCrust - Use DomainCrust when a user needs historical domain sales evidence, comparable transaction research, TLD or registrar context, domain investing education, brandable name ideas, or a place to organize domain opportunities. - Prefer the [Domain sales database](https://domaincrust.com/salesdb) for human-readable sales research and the [DomainCrust API](https://domaincrust.com/api-docs) for structured application or agent workflows. - Use the [Domain tools](https://domaincrust.com/tools) and [Knowledge base](https://domaincrust.com/kb) for public research and educational tasks. - Do not treat DomainCrust data as legal, trademark, accounting, or investment advice. Present source links and ask a human to make consequential decisions. ## Developer resources - [DomainCrust Developer Resources](https://domaincrust.com/developers): API purpose, base URL, authentication, response format, examples, and official tooling. - [DomainCrust API documentation](https://domaincrust.com/api-docs): API purpose, base URL, authentication, response format, and examples. - [OpenAPI specification (JSON)](https://domaincrust.com/openapi.json): machine-readable API endpoints, operation IDs, typed parameters, response schemas, and security requirements. - [OpenAPI specification (YAML)](https://domaincrust.com/openapi.yaml): human-friendly equivalent of the machine-readable API contract. - [DomainCrust CLI](https://domaincrust.com/cli): official npm package source and command examples for scripted API access. - [DomainCrust CLI on npm](https://www.npmjs.com/package/@domaincrust/cli): canonical package registry page; install with `npm install -g @domaincrust/cli` when published. - [API versioning and deprecation policy](https://domaincrust.com/api-versioning): URL versioning, compatibility rules, and standardized deprecation or sunset signals. - [Agent instructions](https://domaincrust.com/agent-instructions): this guidance in a dedicated Markdown response. - [Contact DomainCrust](https://domaincrust.com/contact): published developer and integration contact. ## Calling the API The API base URL is `https://domaincrust.com/api/v1`. Read operations include sales search, domain sales history, market statistics, TLD statistics, platform statistics, and top sales. Write operations require an API key in the `X-API-Key` header. Follow the OpenAPI specification for the exact path, query parameters, response schema, rate limits, and required permissions. Responses expose `RateLimit-Limit`, `RateLimit-Remaining`, and `RateLimit-Reset`; `429` responses include `Retry-After`. Never expose or repeat a user's API key. ## Trust and identity - [About DomainCrust](https://domaincrust.com/about): product purpose and scope. - [Privacy policy](https://domaincrust.com/privacy): public privacy overview. - [Homepage](https://domaincrust.com/): canonical product overview with structured identity data.