> ## Documentation Index
> Fetch the complete documentation index at: https://docs.leadx.com/llms.txt
> Use this file to discover all available pages before exploring further.

# FAQ

> Frequently asked questions about the LeadX API.

<AccordionGroup>
  <Accordion title="How do I authenticate my requests?">
    Include your API key in the `X-API-KEY` header with every request. Requests without a valid key are rejected with a `401 Unauthorized` error. See [Authentication](/getting-started/authentication) for examples in cURL, Python, and Node.js.
  </Accordion>

  <Accordion title="Can I test the API without writing code?">
    Yes. Every endpoint page in this documentation includes an interactive playground. Enter your API key, experiment with parameters, and view live JSON responses directly in your browser.
  </Accordion>

  <Accordion title="Which endpoints support pagination?">
    Pagination is currently available on `POST /v1/ucc/debtor` and `POST /v1/ucc/secured_party`. Use the `page` and `per_page` parameters (max 50 records per page) and iterate using the pagination metadata in each response. See [Pagination](/getting-started/pagination) for details.
  </Accordion>

  <Accordion title="What happens if I exceed the rate limit?">
    The API responds with a `429 Too Many Requests` error, and further requests are temporarily blocked until the time window resets. Rate limits are tracked by client IP address. See [Rate Limiting](/getting-started/rate-limiting) for details.
  </Accordion>

  <Accordion title="How are errors returned?">
    Most endpoints return errors in a standardized format with `error.code`, `error.message`, `error.status`, and an `error.request_id` you can reference when contacting support. See [Troubleshooting and Error Codes](/getting-started/troubleshooting-and-error-codes) for the full reference.
  </Accordion>

  <Accordion title="Can I look up records in bulk?">
    Yes. LeadX provides bulk endpoints for [enriching contacts](/endpoints/contacts/bulk-enrich-contacts), [finding emails](/endpoints/email/bulk-find-emails), and [finding mobile numbers](/endpoints/mobile-number/bulk-find-mobile-numbers).
  </Accordion>

  <Accordion title="How do I get support?">
    Email [info@leadx.com](mailto:info@leadx.com) or [book a demo](https://cal.com/johnsokol/leadx-demo) to talk with the team. Include the `request_id` from any error response to help us troubleshoot faster.
  </Accordion>
</AccordionGroup>