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

# Quickstart

> Make your first request to The Data City API in under five minutes.

This guide walks you from zero to a working API call against The Data City v2 API.

## 1. Get an API key

API keys are issued manually by The Data City. Email [support@thedatacity.com](mailto:support@thedatacity.com) to request one. See [Authentication](/api-reference/guides/authentication) for the full flow.

## 2. Make your first request

Every request needs an `Authorization: Bearer <token>` header. Try fetching details for a UK company by its Companies House number:

```bash theme={null}
curl -X GET 'https://product-api.thedatacity.com/api/v2/companies/12345678' \
  -H 'Authorization: Bearer YOUR_API_KEY'
```

A successful response is a JSON object with the company's classification, financials, and metadata. If you get `{"message":"Unauthenticated."}`, the token is missing or wrong.

## 3. Explore from there

<CardGroup cols={2}>
  <Card title="API reference" icon="code" href="/api-reference">
    Every endpoint, with a live playground.
  </Card>

  <Card title="Authentication" icon="key" href="/api-reference/guides/authentication">
    How tokens work and what to do if yours stops.
  </Card>

  <Card title="Filtering" icon="filter" href="/api-reference/guides/filtering">
    Build a list of companies that match RTICs, CICs, or your own criteria.
  </Card>

  <Card title="Batching" icon="layer-group" href="/api-reference/guides/batching">
    Bulk endpoints and company-number sets for large lists.
  </Card>
</CardGroup>

<Snippet file="need-help.mdx" />