> ## 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).
On update, the `updateStrategy` query parameter decides what the existing record keeps (see below). By default, sent values replace stored ones and empty values are ignored.
## 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.
## Update strategy
The `updateStrategy` query parameter decides what an existing contact keeps:
| Value | Stored value | Empty string sent |
| - | - | - |
| `overwriteIgnoreEmpty` (default) | Replaced | Ignored |
| `overwrite` | Replaced | Cleared |
| `fillEmptyOnly` | Kept | Ignored |
`null` and absent keys never touch a field. Identifiers (`email`, `linkedinUrl`, `linkedinUrlSalesNav`) are never cleared. Under `fillEmptyOnly`, the company link, the owner and the status are kept when set and filled when missing. A new contact receives every value sent. Any other value answers `400 INVALID_UPDATE_STRATEGY`.
```bash theme={"theme":"dracula"}
curl -X POST "https://api.lemlist.com/api/contacts?updateStrategy=fillEmptyOnly" \
-u ":YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{"email": "john@example.com", "jobTitle": "Founder", "phone": "+33600000000"}'
```
Kept values are reported: `warnings` carries a `FIELDS_KEPT` entry with the field names in `params.fields`. It appears under `fillEmptyOnly` on a stored value, and under the default when an empty string is ignored on a filled field, never for an identical value.
```json theme={"theme":"dracula"}
{
"success": true,
"data": { "_id": "ctc_2aB3cD4eF5gH6iJ7k", "jobTitle": "CEO", "phone": "+33600000000", "created": false, "updated": true, "companyLinked": false },
"warnings": [
{ "code": "FIELDS_KEPT", "message": "Fields kept: the record already holds a different value, left unchanged by the update strategy", "params": { "fields": ["jobTitle"] } }
]
}
```
## 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 contact is still written and the response carries an `OWNER_NOT_FOUND` or `INVALID_OWNER_FORMAT` entry in `warnings`. On creation, the contact defaults to the API key owner; on update, the current owner is unchanged.
On an existing contact, `updateStrategy` decides the owner:
| Strategy | Current owner set | No current owner |
| - | - | - |
| `overwriteIgnoreEmpty` (default) and `overwrite` | Replaced by `contactOwner` | Set to `contactOwner` |
| `fillEmptyOnly` | Kept, reported as `ownerId` under `warnings` (`FIELDS_KEPT`) | Set to `contactOwner` |
Without `contactOwner`, the owner is never touched.
## 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: []
tags:
- name: Enrichment Providers
description: >-
The data providers lemlist can call to find an email or a phone.
Internal providers are paid with lemlist credits and always available.
External providers run on your own account: connect one by saving its API
key, and it becomes available to your waterfalls. `GET
/enrichments/providers` is the catalog of provider ids accepted by the
waterfall endpoints.
- name: Enrichment Waterfalls
description: >-
Control which data providers lemlist calls when enriching a contact, and
in which order.
A waterfall is an ordered list of providers for one enrichment `type`
(`email` or `phone`). Providers are tried one after the other until one
returns a result.
Every team has exactly one default waterfall per type (`isDefault: true`).
While its `editor` is `lemlist` it follows the lemlist behaviour:
providers you connected with your own API key are tried first, then
internal providers in a random order. Once a team member edits its
provider list, `editor` becomes that user's id and the list is followed as
is; resetting it hands it back to `lemlist`.
Custom waterfalls (`isDefault: false`) carry `conditions` on the contact
being enriched, keyed by contact property; every key present must match.
When a contact is enriched, lemlist runs a single waterfall: the custom
waterfall of the requested type whose conditions match the contact, or the
default waterfall when none does. If several match, the one with the most
condition keys wins, then the most recently updated. Only that waterfall
runs; when it finds nothing, the enrichment ends without falling back to
another one.
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 is updated as the `updateStrategy` query parameter says (by
default, sent values replace stored ones and empty values are ignored).
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:
- name: updateStrategy
in: query
required: false
description: >-
What an existing record keeps. `overwriteIgnoreEmpty` (default):
sent values replace stored ones, empty values are ignored.
`overwrite`: an empty string clears the field. `fillEmptyOnly`: only
empty fields are filled, identifiers, links, owner and status kept.
A new record receives every value sent. Other values: `400
INVALID_UPDATE_STRATEGY`.
example: fillEmptyOnly
schema:
type: string
enum:
- overwrite
- overwriteIgnoreEmpty
- fillEmptyOnly
default: overwriteIgnoreEmpty
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 contact is still written with an
`OWNER_NOT_FOUND` or `INVALID_OWNER_FORMAT` entry in
`warnings`: the owner defaults to the API key owner on
creation and is unchanged on update. On update it replaces
the current owner, except under `fillEmptyOnly` where it is
only set when the contact has none.
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`.
warnings:
type: array
description: >-
Non-blocking notices: owner or company not resolved, or
`FIELDS_KEPT` when the update strategy kept values you
sent (`params.fields` names them).
items:
type: object
properties:
code:
type: string
description: >-
`OWNER_NOT_FOUND` or `INVALID_OWNER_FORMAT`
(`contactOwner` matches no team member);
`COMPANY_NOT_FOUND_BY_ID`,
`COMPANY_NOT_FOUND_BY_DOMAIN` or
`COMPANY_NOT_FOUND_BY_LINKEDIN_URL` (company not
linked); `FIELDS_KEPT` (values the update strategy
kept).
message:
type: string
params:
type: object
additionalProperties:
anyOf:
- type: string
- type: array
items:
type: string
description: >-
Details: the input echoed back, or `fields` for
`FIELDS_KEPT`.
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: >-
Non-blocking notices: owner or company not resolved, or
`FIELDS_KEPT` when the update strategy kept values you
sent (`params.fields` names them).
items:
type: object
properties:
code:
type: string
description: >-
`OWNER_NOT_FOUND` or `INVALID_OWNER_FORMAT`
(`contactOwner` matches no team member);
`COMPANY_NOT_FOUND_BY_ID`,
`COMPANY_NOT_FOUND_BY_DOMAIN` or
`COMPANY_NOT_FOUND_BY_LINKEDIN_URL` (company not
linked); `FIELDS_KEPT` (values the update strategy
kept).
message:
type: string
params:
type: object
additionalProperties:
anyOf:
- type: string
- type: array
items:
type: string
description: >-
Details: the input echoed back, or `fields` for
`FIELDS_KEPT`.
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`, `INVALID_EMAIL`,
`INVALID_ADDITIONAL_EMAILS`, `INVALID_LINKEDIN_URL`,
`INVALID_FIELD`, `INVALID_USER_FIELD_FORMAT`,
`USER_FIELD_NOT_FOUND`, `CONTACT_VALIDATION_FAILED`,
or `INVALID_UPDATE_STRATEGY`.
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
'404':
description: >-
No contact of the team matches `contactId`
(`CONTACT_NOT_FOUND_BY_ID`).
content:
application/json:
schema:
$ref: '#/components/schemas/ApiErrorEnvelope'
examples:
not-found:
value:
success: false
error:
code: CONTACT_NOT_FOUND_BY_ID
message: No contact found with the provided contactId
'409':
description: >-
An email, LinkedIn or Sales Navigator URL already belongs to another
contact (`CONTACT_IDENTIFIER_CONFLICT`); retrying as is fails again.
content:
application/json:
schema:
$ref: '#/components/schemas/ApiErrorEnvelope'
examples:
conflict:
value:
success: false
error:
code: CONTACT_IDENTIFIER_CONFLICT
message: >-
An identifier (email, linkedinUrl or salesnavUrl)
already belongs to another contact
components:
schemas:
ApiErrorEnvelope:
type: object
description: Error envelope of the contact and company endpoints.
properties:
success:
type: boolean
example: false
error:
type: object
properties:
code:
type: string
description: Machine-readable error code, stable across releases.
message:
type: string
description: Human-readable explanation.
required:
- code
- message
required:
- success
- error
securitySchemes:
basicAuth:
type: http
scheme: basic
````
This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.