Data API Reference

Last Updated: 2026-03-14

The Stellar Data API lets you programmatically access your experiment data. Use it to integrate A/B test results into your own dashboards, reporting tools, or internal platforms.

Authentication

All API requests require a valid API key sent via the Authorization header using the Bearer scheme:

curl -H "Authorization: Bearer stl_YOUR_API_KEY" \
  https://api.gostellar.app/v1/experiments

To generate an API key, go to your Domains page, click View Settings on the domain you want, and look for the API Access section. Only the project owner can create or revoke keys.

Rate Limits

The API is rate-limited to 60 requests per minute per IP address. If you exceed this limit, you will receive a 429 Too Many Requests response. The response includes standard RateLimit-* headers so you can track your remaining quota.

List Experiments

GET /v1/experiments

Returns all experiments for the project associated with your API key.

Query Parameters

Example Request

curl -H "Authorization: Bearer stl_YOUR_API_KEY" \
  "https://api.gostellar.app/v1/experiments?status=running"

Example Response

{
  "experiments": [
    {
      "id": 142,
      "name": "Homepage Hero CTA Test",
      "status": "running",
      "type": "split_url",
      "url": "https://example.com",
      "traffic": 100,
      "started_at": "2026-02-01T00:00:00.000Z",
      "paused_at": null,
      "ended_at": null,
      "created_at": "2026-01-28T14:30:00.000Z"
    },
    {
      "id": 138,
      "name": "Pricing Page Layout",
      "status": "running",
      "type": null,
      "url": "https://example.com/pricing",
      "traffic": 100,
      "started_at": "2026-01-15T00:00:00.000Z",
      "paused_at": null,
      "ended_at": null,
      "created_at": "2026-01-14T10:00:00.000Z"
    }
  ]
}

Get Experiment

GET /v1/experiments/:id

Returns full details for a single experiment, including variants with performance stats, associated conversions, and statistical significance.

Query Parameters

Example Request

curl -H "Authorization: Bearer stl_YOUR_API_KEY" \
  "https://api.gostellar.app/v1/experiments/142?from=2026-02-01&to=2026-02-28"

Example Response

{
  "id": 142,
  "name": "Homepage Hero CTA Test",
  "status": "running",
  "type": "split_url",
  "url": "https://example.com",
  "traffic": 100,
  "started_at": "2026-02-01T00:00:00.000Z",
  "paused_at": null,
  "ended_at": null,
  "created_at": "2026-01-28T14:30:00.000Z",
  "goals": [
    {
      "id": 55,
      "name": "CTA Click",
      "type": "CLICK",
      "value": null,
      "is_main": true
    },
    {
      "id": 60,
      "name": "Signup",
      "type": "PAGE_VISIT",
      "value": null,
      "is_main": false
    }
  ],
  "variants": [
    {
      "id": 301,
      "name": "Control",
      "is_control": true,
      "traffic": 50,
      "url": "https://example.com",
      "unique_visitors": 1243,
      "conversions": 48,
      "conversion_rate": 3.86,
      "squashed_conversions": 45,
      "squashed_conversion_rate": 3.62
    },
    {
      "id": 302,
      "name": "Variant A - New Hero",
      "is_control": false,
      "traffic": 50,
      "url": "https://example.com/new-hero",
      "unique_visitors": 1198,
      "conversions": 62,
      "conversion_rate": 5.18,
      "squashed_conversions": 58,
      "squashed_conversion_rate": 4.84
    }
  ],
  "statistical_significance": 92.3
}

Response Fields

Experiment

Variant

Goal (Conversion)

Error Handling

The API returns standard HTTP status codes. All error responses include a JSON body with an error field:

{
  "error": "Description of what went wrong"
}