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

# Quickstart

> Make your first authenticated Vein API call in under 5 minutes.

The Vein API gives you read-only access to verified portfolio company data,
with full source attribution on every metric.

## 1. Get a test key

Phase 1 keys are issued by hand to design partners. Ask your Vein contact for
a sandbox key. It looks like `vein_sk_test_8aK2nMqP9wF3vR7tB6yX4cZ1jL5hG0sD`.

A test key sees only the data of the company it is bound to. In Phase 1, test keys are issued against sandbox companies, so you can build against them safely.

If your firm already has the **API Keys** panel in Settings, [issuing a key](/api-keys) there does the same thing without waiting on us.

## 2. Make your first call

```bash theme={null}
curl https://api.vein.finance/v1/companies \
  -H "Authorization: Bearer vein_sk_test_YOUR_KEY"
```

You'll get a list envelope back:

```json theme={null}
{
  "object": "list",
  "data": [
    {
      "id": "sandbox_acme",
      "object": "company",
      "name": "Acme Corp",
      "mode": "startup",
      "sector": "Technology",
      "stage": "Seed",
      "created_at": "2026-01-15T08:30:00Z",
      "relationship": {
        "type": "lead_investor",
        "investment_amount": 2000000,
        "ownership_percent": 12.5
      }
    }
  ],
  "next_cursor": null,
  "has_more": false,
  "url": "/v1/companies"
}
```

## 3. Paginate

Pass `limit` (max 100) and the `next_cursor` from the previous response:

```bash theme={null}
curl "https://api.vein.finance/v1/companies?limit=50&cursor=eyJpZCI6Ii4uLiJ9" \
  -H "Authorization: Bearer vein_sk_test_YOUR_KEY"
```

When `has_more` is `false`, `next_cursor` is `null` and you've reached the end.

## Next steps

* [Authentication](/authentication): key format, scopes, and rotation.
* API Reference: every endpoint, generated from our OpenAPI spec.