Quickstart

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 there does the same thing without waiting on us.

2. Make your first call

curl https://api.vein.finance/v1/companies \
  -H "Authorization: Bearer vein_sk_test_YOUR_KEY"

You’ll get a list envelope back:

{
  "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:

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: key format, scopes, and rotation.
API Reference: every endpoint, generated from our OpenAPI spec.

Get Started

For Companies

For Investors

Your Account

API Reference

Support

1. Get a test key

2. Make your first call

3. Paginate

Next steps

​1. Get a test key

​2. Make your first call

​3. Paginate

​Next steps

1. Get a test key

2. Make your first call

3. Paginate

Next steps