---
title: "Add A/B test variant"
method: POST
path: "/ab-tests/{abTestId}/variants"
tags: ["A/B Tests"]
---

# Add A/B test variant

`POST /ab-tests/{abTestId}/variants`

Adds a variant to a draft campaign or sequence A/B test. Sequence variants receive an independent email template. The body defaults to the control email when blocks are omitted. Sequence tests whose parent sequence is active require confirmLiveChange.

## Path parameters

- `abTestId` string, required

## Request body

- object
  - `subject` string, required — Variant subject line.
  - `previewText` string — Variant preview text.
  - `blocks` EmailBlock[] — Variant body blocks. Defaults to the campaign or sequence control email blocks.
    - `id` string
    - `type` 'text' | 'html' | 'heading' | 'list' | 'button' | 'spacer' | 'divider' | 'image' | 'columns' | 'conditional-group' | 'repeat' | 'card' | 'cta' | 'social' | 'logo' | 'header' | 'footer' | 'video' | 'product' | 'discount-code' | 'code' | 'countdown' | 'hero' | 'testimonial' | 'gallery' | 'badge' | 'table' | 'features' | 'image-card' | 'pricing' | 'author' | 'article' | 'rating' | 'stats' | 'steps' | 'product-grid' | 'poll', required
    - `content` string — Content for text, html, and heading-like blocks.
    - `styles` object — Per-block visual styles. For compatibility, style fields such as backgroundColor, backgroundOpacity, borderColor, borderWidth, and borderRadius can also be supplied at the block top level and are normalized into this object.
      - `paddingTop` number
      - `paddingBottom` number
      - `paddingLeft` number
      - `paddingRight` number
      - `backgroundColor` string
      - `backgroundOpacity` number — Background opacity percentage from 0 to 100.
      - `textColor` string
      - `textAlign` 'left' | 'center' | 'right'
      - `borderRadius` number
      - `borderColor` string
      - `borderWidth` number
      - `bleed` boolean — Stretch the block edge-to-edge across the email container. Top-level blocks only.
    - `conditions` object[] — Optional per-block display rules. The block renders only when every rule matches. The same shape is used for a conditional-group block's top-level `conditions`.
      - `id` string, required
      - `field` 'variable' | 'attribute' | 'email' | 'firstName' | 'lastName', required — `variable` resolves a merge-tag path from the transactional send `variables` or an automation `event` payload (nested paths like `order.total` or `event.plan` work). `attribute` reads a stored subscriber attribute. `email`, `firstName`, and `lastName` read core subscriber fields.
      - `operator` 'is' | 'is_not' | 'contains' | 'not_contains' | 'gt' | 'gte' | 'lt' | 'lte' | 'is_empty' | 'is_not_empty', required
      - `value` string, required — For `variable` and `attribute`, use `name:value` - the part before the colon is the variable path or attribute name, and the part after it is the comparison value. For `email`, `firstName`, and `lastName`, provide the plain comparison string.
  - `confirmLiveChange` boolean — Required as true when the A/B test belongs to an active sequence, because new variants immediately enter the live rotation.

## Response `200`

Variant added

- object
  - `success` boolean
  - `abTest` ABTest
    - `id` string
    - `companyId` string
    - `kind` 'campaign' | 'sequence' — Identifies which settings model applies to this test.
    - `campaignId` string, nullable
    - `automationNodeId` string, nullable
    - `name` string, nullable
    - `status` string
    - `testPercentage` integer — Campaign test audience percentage. Sequence tests retain the legacy internal sentinel value 100; use settings instead.
    - `testDurationMinutes` integer — Campaign test duration. Sequence tests retain the legacy internal sentinel value 0; use settings instead.
    - `winnerCriteria` string
    - `testType` 'subject' | 'content' — Effective sequence variant strategy. Present for sequence tests.
    - `winnerThreshold` integer — Effective sequence recipient threshold. Present for sequence tests.
    - `settings` object — Effective settings for this test kind. Campaign tests return testPercentage, testDurationMinutes, and winnerCriteria; sequence tests return testType, winnerThreshold, and winnerCriteria.
    - `winningVariantId` string, nullable
    - `winnerSelectedAt` string, date-time, nullable
    - `testStartedAt` string, date-time, nullable
    - `testEndsAt` string, date-time, nullable
    - `createdAt` string, date-time
    - `updatedAt` string, date-time
    - `variants` ABTestVariant[]
      - `id` string
      - `variantId` string
      - `abTestId` string
      - `label` string
      - `variantLabel` string
      - `emailId` string
      - `subject` string
      - `previewText` string, nullable
      - `blocks` EmailBlock[]
        - `id` string
        - `type` 'text' | 'html' | 'heading' | 'list' | 'button' | 'spacer' | 'divider' | 'image' | 'columns' | 'conditional-group' | 'repeat' | 'card' | 'cta' | 'social' | 'logo' | 'header' | 'footer' | 'video' | 'product' | 'discount-code' | 'code' | 'countdown' | 'hero' | 'testimonial' | 'gallery' | 'badge' | 'table' | 'features' | 'image-card' | 'pricing' | 'author' | 'article' | 'rating' | 'stats' | 'steps' | 'product-grid' | 'poll', required
        - `content` string — Content for text, html, and heading-like blocks.
        - `styles` object — Per-block visual styles. For compatibility, style fields such as backgroundColor, backgroundOpacity, borderColor, borderWidth, and borderRadius can also be supplied at the block top level and are normalized into this object.
          - `paddingTop` number
          - `paddingBottom` number
          - `paddingLeft` number
          - `paddingRight` number
          - `backgroundColor` string
          - `backgroundOpacity` number — Background opacity percentage from 0 to 100.
          - `textColor` string
          - `textAlign` 'left' | 'center' | 'right'
          - `borderRadius` number
          - `borderColor` string
          - `borderWidth` number
          - `bleed` boolean — Stretch the block edge-to-edge across the email container. Top-level blocks only.
        - `conditions` object[] — Optional per-block display rules. The block renders only when every rule matches. The same shape is used for a conditional-group block's top-level `conditions`.
          - `id` string, required
          - `field` 'variable' | 'attribute' | 'email' | 'firstName' | 'lastName', required — `variable` resolves a merge-tag path from the transactional send `variables` or an automation `event` payload (nested paths like `order.total` or `event.plan` work). `attribute` reads a stored subscriber attribute. `email`, `firstName`, and `lastName` read core subscriber fields.
          - `operator` 'is' | 'is_not' | 'contains' | 'not_contains' | 'gt' | 'gte' | 'lt' | 'lte' | 'is_empty' | 'is_not_empty', required
          - `value` string, required — For `variable` and `attribute`, use `name:value` - the part before the colon is the variable path or attribute name, and the part after it is the comparison value. For `email`, `firstName`, and `lastName`, provide the plain comparison string.
      - `testSends` integer
      - `testOpens` integer
      - `testClicks` integer
      - `isWinner` boolean
      - `localizations` object[]
      - `createdAt` string, date-time
  - `warnings` string[] — Non-blocking advisories about the blocks that were written. The write succeeded. Present when a field was not part of the block schema and was discarded, or when a supported field does not control what its name suggests for that block type - for example styles.backgroundColor on a button colors the band behind the button while the fill comes from buttonColor. Each message names the offending path and the fields that block does accept. Absent when there is nothing to report.

## Other responses

- `400` — Non-draft test, variant limit reached, missing owner, invalid blocks, or missing live-change confirmation
- `401` — Unauthorized
- `404` — A/B test not found
- `500` — Variant could not be created

## Changes

- **2026-07-29** `d03612b5fabd` — 1 info
  - added the optional property `warnings` to the response with the `200` status
- **2026-07-25** `b58891ac1cde` — 4 info
  - added the optional property `abTest/kind` to the response with the `200` status
  - added the optional property `abTest/settings` to the response with the `200` status
  - added the optional property `abTest/testType` to the response with the `200` status
  - added the optional property `abTest/winnerThreshold` to the response with the `200` status
- **2026-07-18** `09f0c32988fb` — 1 info
  - added the new optional request property `confirmLiveChange`
- **2026-07-16** `d7ea66dede72` — 14 warning, 16 info
  - added the new `article` enum value to the `abTest/variants/items/blocks/items/type` response property for the response status `200`
  - added the new `author` enum value to the `abTest/variants/items/blocks/items/type` response property for the response status `200`
  - added the new `badge` enum value to the `abTest/variants/items/blocks/items/type` response property for the response status `200`
  - added the new `features` enum value to the `abTest/variants/items/blocks/items/type` response property for the response status `200`
  - …26 more
- …earlier changes not shown

[Full history](https://skmtc.dev/sequenzy/apis/sequenzy-api/changes/ab-tests/:abTestId/variants/post.md)

---

[API](https://skmtc.dev/sequenzy/apis/sequenzy-api.md) · [All operations](https://skmtc.dev/sequenzy/apis/sequenzy-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/sequenzy/sequenzy-api/revisions/6db218f95cf4/schema)