> ## 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 a new contact or updates an existing one based on email or LinkedIn URL.
# Add and update contact
export const SnippetObjectReference = ({objectName, objectPath = null}) => {
const lowerCaseObjectName = objectName.toLowerCase();
if (lowerCaseObjectName === 'lead' || lowerCaseObjectName === 'leads') {
return
This endpoint uses the {objectName} object. Make sure to also check the {lowerCaseObjectName === 'lead' ? 'Contact' : 'Lead'} object to understand the distinction between the two.
;
}
return
This endpoint uses the {objectName} object.
;
};
Creates a new contact in your CRM, or updates an existing one if a contact with the same `email`, `linkedinUrl`, or `linkedinUrlSalesNav` already exists (upsert).
During updates, only non-empty fields are applied — null or empty values are ignored to preserve existing data.
## Upsert matching
At least one identifier is required:
| Identifier | Description |
| --------------------- | -------------------------------------------------------------------------------------------- |
| `contactId` | Existing contact ID — updates a specific contact directly, bypassing email/LinkedIn matching |
| `email` | Primary email address — used as the main unique key |
| `linkedinUrl` | LinkedIn profile URL — used as an alternative unique key |
| `linkedinUrlSalesNav` | LinkedIn Sales Navigator profile URL — used as an alternative unique key |
If a contact with the same `email`, `linkedinUrl`, or `linkedinUrlSalesNav` already exists, the endpoint updates it instead of creating a duplicate.
When `contactId` is provided, the contact is matched by its ID directly — `email` and `linkedinUrl` are not required and are not used for matching (they are stored as data if provided).
`contactId` can only be used to **update** an existing contact. It cannot be used to create a new contact — use `email` or `linkedinUrl` for creation.
## Linking to a company
You can link the contact to a company that already exists in your lemlist CRM using one of the following fields (in order of priority):
| Field | Description |
| -------------------- | ------------------------------------------------------------------------- |
| `companyId` | Direct company ID — takes priority over the others |
| `companyDomain` | Company domain (e.g. `lemlist.com`) — used if `companyId` is not provided |
| `companyLinkedinUrl` | Company LinkedIn URL — used as a last resort |
When a company is successfully linked, the response includes `companyLinked: true` and the `companyId`.
## Owner assignment
You can assign an owner to the contact using the `contactOwner` field. Accepted formats:
| Format | Example |
| ----------------- | ----------------------- |
| User ID | `usr_2aB3cD4eF5gH6iJ7k` |
| Team member email | `john@yourcompany.com` |
If the provided value does not match a team member (invalid format, unknown email, or unknown user ID), the owner is **silently ignored** — no error or warning is returned. On creation, the contact defaults to the API key owner.
## OpenAPI
````yaml post /contacts
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:
/contacts:
post:
tags:
- Contacts
summary: Add and update contact
description: >-
Creates a new contact or updates an existing one (upsert). If a contact
with the same email, LinkedIn URL, or Sales Navigator URL already
exists, it will be updated with the provided non-empty fields. Null or
empty values are ignored during updates to preserve existing data. You
can target an existing contact directly by providing `contactId`,
bypassing email/LinkedIn matching. You can optionally link the contact
to a company by providing `companyId`, `companyDomain`, or
`companyLinkedinUrl`.
parameters: []
requestBody:
required: true
content:
application/json:
schema:
type: object
properties:
contactId:
type: string
description: >-
Existing contact ID. Updates a specific contact by ID,
bypassing email/LinkedIn matching. Can only be used to
update an existing contact, not to create a new one. When
provided, `email` and `linkedinUrl` are not required. At
least one of `contactId`, `email`, `linkedinUrl`, or
`linkedinUrlSalesNav` is required.
email:
type: string
description: >-
Contact email address. Used as a unique key for upsert
matching. At least one of `contactId`, `email`,
`linkedinUrl`, or `linkedinUrlSalesNav` is required.
linkedinUrl:
type: string
description: >-
LinkedIn profile URL. Used as an alternative unique key for
upsert matching. At least one of `contactId`, `email`,
`linkedinUrl`, or `linkedinUrlSalesNav` is required.
linkedinUrlSalesNav:
type: string
description: >-
LinkedIn Sales Navigator profile URL. Used as an alternative
unique key for upsert matching.
additionalEmails:
type: array
items:
type: string
description: >-
Additional email addresses for the contact. Each must be a
valid email address.
firstName:
type: string
description: Contact first name.
lastName:
type: string
description: Contact last name.
phone:
type: string
description: Contact phone number.
jobTitle:
type: string
description: >-
Contact job title. If a company is linked, this is saved as
part of the job data.
jobDescription:
type: string
description: >-
Contact job description. If a company is linked, this is
saved as part of the job data.
picture:
type: string
description: URL of the contact's profile picture.
timezone:
type: string
description: Contact timezone.
industry:
type: string
description: Contact industry.
languages:
type: string
description: Contact languages.
location:
type: string
description: Contact location.
skills:
type: string
description: Contact skills.
summary:
type: string
description: Contact summary or bio.
tagline:
type: string
description: Contact tagline.
contactOwner:
type: string
description: >-
Owner of the contact. Can be a user ID (e.g. `usr_...`) or a
team member's email address. If the provided value does not
match a team member, the owner defaults to the API key
owner.
source:
type: string
description: >-
Origin of the contact record. Set on creation only and
cannot be updated afterwards. Defaults to `api`.
default: api
companyId:
type: string
description: >-
ID of a company already existing in lemlist to link to this
contact. Takes priority over `companyDomain` and
`companyLinkedinUrl`.
companyDomain:
type: string
description: >-
Domain of a company already existing in lemlist to link to
this contact (e.g. `lemlist.com`). Used if `companyId` is
not provided.
companyLinkedinUrl:
type: string
description: >-
LinkedIn URL of a company already existing in lemlist to
link to this contact. Used if `companyId` and
`companyDomain` are not provided.
additionalProperties:
description: >-
Any additional key is treated as a custom field. Custom fields
must be registered in the team's CRM field registry
beforehand.
example:
email: jane.smith@example.com
firstName: Jane
lastName: Smith
linkedinUrl: https://linkedin.com/in/janesmith
jobTitle: Product Manager
companyDomain: acme.com
responses:
'200':
description: Existing contact updated (upsert matched by email or LinkedIn URL)
content:
application/json:
schema:
type: object
properties:
success:
type: boolean
data:
type: object
description: >-
Same shape as the 201 response, with `created: false` and
`updated: true`.
example:
success: true
data:
_id: ctc_xW8Ou6C03Csv8vatp
teamId: tea_8QvkOiBfPdb2ZRhHi
emails:
- value: jane.smith@example.com
fields:
firstName: Jane
lastName: Smith
jobTitle: Product Manager
ownerId: usr_ahfFktBBHUIxbVG5P
source: api
createdAt: '2025-10-28T00:40:37.917Z'
createdBy: usr_ahfFktBBHUIxbVG5P
unsubscribed: false
created: false
updated: true
companyLinked: false
'201':
description: Contact created successfully
content:
application/json:
schema:
type: object
properties:
success:
type: boolean
data:
type: object
properties:
_id:
type: string
description: Unique contact identifier
teamId:
type: string
description: Team ID
emails:
type: array
description: Contact email addresses
items:
type: object
properties:
value:
type: string
linkedinUrl:
type: string
description: LinkedIn profile URL
linkedinUrlSalesNav:
type: string
description: LinkedIn Sales Navigator URL
fields:
type: object
description: >-
Key/value fields (firstName, lastName, phone,
jobTitle, custom fields, etc.)
additionalProperties: true
ownerId:
type: string
description: Owner user ID
companyId:
type: string
description: >-
Linked company ID (present only when a company was
linked)
source:
type: string
description: Record origin
createdAt:
type: string
format: date-time
description: Creation timestamp
createdBy:
type: string
description: User ID who created the record
unsubscribed:
type: boolean
description: Whether the contact is unsubscribed
created:
type: boolean
description: >-
`true` when a new contact was created, `false` when an
existing contact was updated.
updated:
type: boolean
description: >-
Present and set to `true` only when an existing
contact was updated (i.e. `created` is `false`).
companyLinked:
type: boolean
description: >-
Whether a company was successfully linked to the
contact.
warnings:
type: array
description: Optional warnings (e.g. company resolution issues).
items:
type: object
properties:
code:
type: string
message:
type: string
example:
success: true
data:
_id: ctc_xW8Ou6C03Csv8vatp
teamId: tea_8QvkOiBfPdb2ZRhHi
emails:
- value: jane.smith@example.com
linkedinUrl: https://www.linkedin.com/in/janesmith
fields:
firstName: Jane
lastName: Smith
jobTitle: Product Manager
ownerId: usr_ahfFktBBHUIxbVG5P
source: api
createdAt: '2025-10-28T00:40:37.917Z'
createdBy: usr_ahfFktBBHUIxbVG5P
unsubscribed: false
created: true
companyLinked: true
companyId: cpn_gG7PsmZFpEAnpMCHO
'400':
description: Validation error
content:
application/json:
schema:
type: object
properties:
success:
type: boolean
error:
type: object
properties:
code:
type: string
description: >-
Error code: `MISSING_IDENTIFIER`,
`INVALID_CONTACT_ID`, `CONTACT_NOT_FOUND_BY_ID`,
`INVALID_EMAIL`, `INVALID_ADDITIONAL_EMAILS`,
`INVALID_LINKEDIN_URL`, `INVALID_FIELD`, or
`CONTACT_VALIDATION_FAILED`.
message:
type: string
example:
success: false
error:
code: MISSING_IDENTIFIER
message: >-
At least one identifier is required: email, linkedinUrl or
contactId
'401':
description: The authentication you supplied is incorrect
content:
text/plain:
example: The authentication you supplied is incorrect
components:
securitySchemes:
basicAuth:
type: http
scheme: basic
````