A/B Testing

Run A/B tests by splitting your subscriber list across multiple email variants. Compare performance to find the most effective subject line, content, or design.

tip

For the full request/response schema, see the interactive API Reference at /docs on your Posta instance.

Creating an A/B Test Campaign

Enable A/B testing when creating a campaign:

POST /api/v1/workspaces/current/campaigns

{
  "name": "Subject Line Test",
  "subject": "Default subject",
  "from_email": "news@example.com",
  "template_id": 5,
  "list_id": 3,
  "ab_test_enabled": true,
  "ab_test_variants": [
    {
      "name": "Variant A",
      "split_percentage": 50
    },
    {
      "name": "Variant B",
      "split_percentage": 50
    }
  ]
}

curl -X POST http://localhost:9000/api/v1/workspaces/current/campaigns \
  -H "Authorization: Bearer <jwt>" \
  -H "X-Posta-Workspace-Id: 1" \
  -H "Content-Type: application/json" \
  -d '{"name":"Subject Line Test","subject":"Default subject","from_email":"news@example.com","template_id":5,"list_id":3,"ab_test_enabled":true,"ab_test_variants":[{"name":"Variant A","split_percentage":50},{"name":"Variant B","split_percentage":50}]}'

Requirements

• Minimum 2 variants required
• Split percentages must sum to exactly 100
• Campaign must be in draft status to configure variants

Variant Fields

Field	Description
name	Variant identifier (e.g., "Variant A", "Short Subject")
split_percentage	Percentage of the subscriber list that receives this variant

How It Works

When the campaign is sent, Posta randomly splits the subscriber list according to the configured percentages. Each subscriber receives exactly one variant.

Tracking Results

Use the campaign analytics endpoint to compare variant performance:

GET /api/v1/workspaces/current/campaigns/{id}/analytics

curl http://localhost:9000/api/v1/workspaces/current/campaigns/42/analytics \
  -H "Authorization: Bearer <jwt>" \
  -H "X-Posta-Workspace-Id: 1"

The response includes delivery stats broken down by variant, allowing you to compare open rates, click rates, and other metrics across variants.

Campaign Messages

View individual messages sent for a campaign:

GET /api/v1/workspaces/current/campaigns/{id}/messages?page=0&size=20

curl "http://localhost:9000/api/v1/workspaces/current/campaigns/42/messages?page=0&size=20" \
  -H "Authorization: Bearer <jwt>" \
  -H "X-Posta-Workspace-Id: 1"

Each message includes which variant was sent to that subscriber.