A/B tests let you attach competing variants to a campaign and, once results are in, promote the winning variant's content back onto the parent campaign. Each variant is created with its own call, tied to an existing campaign that has not started sending.

Auth scope: listing requires read, send, or send:marketing; creating a variant or selecting a winner requires send or send:marketing.

List A/B tests

GET/mail/v1/ab-tests

List A/B tests for the authenticated account. The response combines campaign A/B-test variants and subject-line tests; each entry carries a source field (campaign or subject) identifying which it is.

Query parameters

pagenumberquerydefault: 1

Page number (1-based).

limitnumberquerydefault: 20

Results per page — max 50.

typestringquery

Restrict to one source: campaign (campaign A/B variants) or subject (subject-line tests). Omit to return both.

Response fields

successboolean

true when the request succeeded.

dataArray<object>

Combined test rows, newest first. Campaign entries include id, campaign_id, variant, test_type, subject, preheader, from_name, send_percent, emails_sent, opens, clicks, winner_selected_at, created_at, and source: "campaign".

paginationobject

page, limit, total, and totalPages.

Request

curl "https://api.misar.io/mail/v1/ab-tests?page=1&limit=20&type=campaign" \
  -H "Authorization: Bearer msk_YOUR_API_KEY"

200 — OK

{
  "success": true,
  "data": [
    {
      "id":                 "3fa85f64-5717-4562-b3fc-2c963f66afa6",
      "campaign_id":        "9c1e2b7a-0d44-4f8a-9b1e-2c963f66afa6",
      "variant":            "A",
      "test_type":          "subject",
      "subject":            "Your exclusive offer inside",
      "preheader":          null,
      "from_name":          null,
      "send_percent":       50,
      "emails_sent":        500,
      "opens":              180,
      "clicks":             45,
      "winner_selected_at": null,
      "created_at":         "2026-04-01T08:00:00Z",
      "source":             "campaign"
    }
  ],
  "pagination": { "page": 1, "limit": 20, "total": 2, "totalPages": 1 }
}

Create an A/B test variant

POST/mail/v1/ab-tests

Add one variant to a campaign's A/B test. Call this once per variant (e.g. once for A, once for B). The campaign must not be in sending or sent status. Creating the first variant sets ab_test_enabled on the campaign.

Request body

campaign_idUUIDbodyrequired

Campaign to attach the variant to.

variantstringbodyrequired

Variant identifier, 1–5 chars (e.g. A, B). Must be unique per campaign.

test_typestringbodydefault: content

What this variant changes — one of content, subject, send_time, from_name, preheader.

subjectstringbody

Override subject line (max 255) — supports merge tags.

preheaderstringbody

Override preheader text (max 255).

body_htmlstringbody

Override HTML body.

from_namestringbody

Override sender display name (max 100).

send_percentnumberbodydefault: 50

Percentage of the list to send this variant to (1–99).

send_time_aISO 8601body

Send time for the first split, used with test_type: "send_time".

send_time_bISO 8601body

Send time for the second split.

auto_select_winnerbooleanbodydefault: false

Automatically promote a winner once the wait window elapses.

winner_wait_hoursnumberbodydefault: 4

Hours to measure before an automatic winner is picked (1–168).

Response fields

successboolean

true when the variant was created.

dataobject

The created variant row, including id, campaign_id, variant, test_type, send_percent, winner_selected_at, and created_at.

Request

curl -X POST https://api.misar.io/mail/v1/ab-tests \
  -H "Authorization: Bearer msk_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "campaign_id":  "9c1e2b7a-0d44-4f8a-9b1e-2c963f66afa6",
    "variant":      "B",
    "test_type":    "subject",
    "subject":      "{{first_name}}, we have something special for you",
    "send_percent": 50
  }'

201 — Created

{
  "success": true,
  "data": {
    "id":                 "7c9e6679-7425-40de-944b-e07fc1f90ae7",
    "campaign_id":        "9c1e2b7a-0d44-4f8a-9b1e-2c963f66afa6",
    "variant":            "B",
    "test_type":          "subject",
    "subject":            "{{first_name}}, we have something special for you",
    "send_percent":       50,
    "winner_selected_at": null,
    "created_at":         "2026-04-01T08:05:00Z"
  }
}

Select the winning variant

POST/mail/v1/ab-tests/:id/winner

Pick the winning variant. The winning variant's content is applied to the parent campaign, and winner_selected_at is stamped.

Path parameters

idUUIDpathrequired

ID of the A/B test (the campaign's test group).

Request body

winner_variantstringbodyrequired

Identifier of the winning variant (1–5 chars), matching a variant value on the test.

metricstringbodydefault: opens

Metric the winner was chosen on — one of opens, clicks, revenue, conversions.

Response fields

successboolean

true when the winner was applied.

dataobject

ab_test_id, campaign_id, winner_variant, metric, winner_selected_at, and applied_to_campaign (the subject, body_html, and from_name written onto the campaign).

Request

curl -X POST https://api.misar.io/mail/v1/ab-tests/3fa85f64-5717-4562-b3fc-2c963f66afa6/winner \
  -H "Authorization: Bearer msk_YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "winner_variant": "B", "metric": "opens" }'

200 — OK

{
  "success": true,
  "data": {
    "ab_test_id":         "3fa85f64-5717-4562-b3fc-2c963f66afa6",
    "campaign_id":        "9c1e2b7a-0d44-4f8a-9b1e-2c963f66afa6",
    "winner_variant":     "B",
    "metric":             "opens",
    "winner_selected_at": "2026-04-01T12:00:00Z",
    "applied_to_campaign": {
      "subject":   "{{first_name}}, we have something special for you",
      "body_html": null,
      "from_name": null
    }
  }
}

Status codes

200 — Winner selected and applied.
201 — Variant created.
400 — Validation failed, missing test id, or invalid JSON body.
403 — API key lacks the required scope.
404 — Campaign not found / not owned, or the named variant does not exist for the test.
409 — Campaign already sending/sent, or a variant with that identifier already exists.
415 — Content-Type is not application/json.

A/B Testing

List A/B tests

Create an A/B test variant

Select the winning variant

Status codes

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