> ## Documentation Index
> Fetch the complete documentation index at: https://developer.lemlist.com/llms.txt
> Use this file to discover all available pages before exploring further.
> Creates variant B of an A/B test on an email step, prefilled from variant A.
# Create A/B Test Variant
A/B testing requires at least the **Email Pro** plan.
A/B testing lets you compare two versions of a single email step. Calling this
endpoint creates a **variant B** email template, prefilled with a copy of
variant A's subject, content, and config, and starts the test: leads going
through the step are split between variant A and variant B.
Once created, edit variant B with
[Update A/B Test Variant](/api-reference/endpoints/sequences/update-ab-test-variant),
read it with
[Get A/B Test Variant](/api-reference/endpoints/sequences/get-ab-test-variant),
and conclude the test with
[Select A/B Test Winner](/api-reference/endpoints/sequences/select-ab-test-winner).
## Scope and constraints
* A/B testing is only supported on **email** steps.
* The step must have an email template (variant A) and must not already run an
A/B test.
* As with other step edits, the test cannot be created while the campaign is
running on a non-editable sequence.
* This endpoint covers A/B testing on a **single step** only.
The response returns variant B's content (`subject`, `message`, config) along
with the `abTest` flag and the new `emailTemplateBId`.
## OpenAPI
````yaml post /sequences/{sequenceId}/steps/{stepId}/ab-test
openapi: 3.0.0
info:
title: lemlist API
version: 1.0.0
description: >-
Welcome to the lemlist Developer Documentation.
lemlist is very customizable and open. You'll find on this page all the API
and integration you can do with lemlist.
# Rate Limit
lemlist's API rate limits requests in order to prevent abuse and overload of
our services.
Rate limits are applied on all routes and per API key performing the
request.
The rate limits are **20** requests per **2** seconds.
The response provides any information you may need about it:
| Header | Description |
| --- | --- |
| Retry-After | The number of seconds in which you can retry |
| X-RateLimit-Limit | The maximum requests in that time |
| X-RateLimit-Remaining | The number of remaining requests you can make |
| X-RateLimit-Reset | The date when the rate limit will reset |
_Example of values for the rate limit headers_
``` json
{
"Retry-After": 2,
"X-RateLimit-Limit": 20,
"X-RateLimit-Remaining": 7,
"X-RateLimit-Reset" : "Tue Feb 16 2021 09:02:42 GMT+0100 (Central European Standard Time)"
}
```
# Definitions
## Team
A team is the entity of lemlist that can handle users and billing.
## Credits
Credits are the coins a team uses to enrich emails, LinkedIn URLs, etc. via
the enrich route. Each enrichment feature needs a certain amount of credits
to run.
## User
You use a user account to connect to lemlist and send messages via the
connected emails or LinkedIn account.
## Campaign
A campaign is the entity to automate outreach. A campaign has multiple
sequences composed of steps.
## Lead
A lead is a person that you try to contact via a campaign.
## Activity
An activity is the history of all the steps.
## Unsubscribe
An unsubscribe occurs when a person decides they don't want to receive
emails from you anymore.
# Authentication
All API routes use the dedicated subdomain `api.lemlist.com`.
lemlist uses API keys to allow access to the API. You can get your lemlist
API key at our [integration
page](https://app.lemlist.com/settings/integrations).
You need to add the `Authorization` header using the `Basic` authentication
type. `login:password` **where the login is always empty and the password is
the API key**.
⚠️ **Don't forget to add the semicolon (**`:`**) before your API key in curl
command.**
> To authorize, use this code:
``` shell
curl https://api.lemlist.com/api/team \
--user ":YourApiKey"
```
**Make sure to replace** **`YourApiKey`** **with your API key.**
# Give feedback
If you want to report a bug, ask for data, or share with us a use case,
please fill this [form](https://lemlist.typeform.com/to/mfVlkyGf). It will
help us centralize your needs!
servers:
- url: https://api.lemlist.com/api
security:
- basicAuth: []
paths:
/sequences/{sequenceId}/steps/{stepId}/ab-test:
parameters:
- name: sequenceId
in: path
required: true
description: The unique identifier of the sequence
example: seq_lkCSKd32qSZZTe5Ru
schema:
type: string
- name: stepId
in: path
required: true
description: The unique identifier of the step
example: stp_V0JHmSpWiO0rxHUkz
schema:
type: string
post:
tags:
- Sequences
summary: Create A/B Test Variant
description: >-
Creates variant B of an A/B test on an email step, prefilled from
variant A, and starts the test (leads are split between A and B).
Requires the Email Pro plan.
parameters: []
responses:
'200':
description: Variant B created
content:
application/json:
schema:
type: object
properties:
stepId:
type: string
abTest:
oneOf:
- type: boolean
- type: string
enum:
- A
- B
emailTemplateBId:
type: string
description: Email template ID of variant B
subject:
type: string
description: Variant B email subject
message:
type: string
description: Variant B email body (HTML)
altMessage:
type: string
cc:
type: array
items:
type: string
plainText:
type: boolean
example:
stepId: stp_V0JHmSpWiO0rxHUkz
abTest: true
emailTemplateBId: etp_9aZ2k1QwErTyUiOp3
subject: Quick question, {{firstName}}
message: Hi {{firstName}}, ...
'400':
description: >-
Bad request (e.g. step is not an email step, has no template,
already runs an A/B test, or the campaign is running)
content:
text/plain:
example: A/B test already exists on this step
'401':
description: The authentication you supplied is incorrect
content:
text/plain:
example: The authentication you supplied is incorrect
'402':
description: A/B testing requires at least the Email Pro plan
content:
text/plain:
example: route is available starting emailPro plan
'404':
description: Sequence, step, or A/B test variant not found
content:
text/plain:
example: No A/B test variant on this step
'405':
description: Method not allowed
components:
securitySchemes:
basicAuth:
type: http
scheme: basic
````