> ## 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 custom field on contacts or companies, or updates the one of that name, under the rules of the lemlist app. # Create or Update Field ## OpenAPI ````yaml post /fields 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: /fields: post: tags: - Fields summary: Create or Update Field description: >- Creates a custom field on contacts or companies, or updates the one the entity already has under that `name`, under the rules of the lemlist app: the same reserved names, the same type conversions, the same permission. **Create.** No field of that `name` on the entity: it is created, as the **New field** button does in the app. Any API key may create a field. The field is created on behalf of the user of the API key and logged in the team activity feed. Once created, write it through `POST /contacts` or `POST /companies` with its `name` as the key. A new contact field is then filled in the background from data lemlist already holds (the LinkedIn data of enriched contacts, the lead variable of the same name in your campaigns). **Update.** A field of that `name` exists: the call updates it, and the API key user needs the **Update contact & companies fields** permission, as in the app (`403` otherwise, even when nothing would change). What can change: - `label`, when sent and different; - `type`, only to `text` or `multilineText`, from any type but `phone` and `user`: the conversions the app offers. The stored values are converted, as in the app. Any other `type` than the stored one answers `400 TYPE_CHANGE_NOT_ALLOWED`. Note that the app promotes a `text` field to `multilineText` on its own when a value with a line break reaches it (import, CRM, API), and `GET /fields` then lists it as `multilineText`: replaying a body with `type: "text"` converts it back and flattens the line breaks, as the app's **Change type** menu does; - the options of a `select`, through `upsertOptions` (added when missing, never removed), `renameOptions` (the contacts or companies holding the old value are rewritten to the new one) and `removeOptions` (the contacts or companies holding the option are cleared). Applied in that order: renames, removals, additions. A select keeps at least one option. Options are matched as in the app, regardless of case and surrounding spaces: `gold` matches an existing `Gold`, renaming `Gold` to `GOLD` only changes its case, and values are stored without surrounding spaces, so a value written on a contact or company matches them. An operation already applied reads as done (a rename whose source is gone while its target exists, a removal of an absent option). Sending the same body again changes nothing and answers `200` with empty `changes`. Two calls changing the options of the same field at the same time: the one planned from a list that changed meanwhile answers `409 FIELD_CHANGED_RETRY` and writes nothing (the options are written first, before any `label` change); read the field again and replay the call. **Name.** `name` is the key your integrations write to, and never changes afterwards: it must start with a lowercase letter, followed by letters and digits only. `label` is optional and defaults to `name` on creation. **Types.** `select` is created with its `upsertOptions` (at least one). A `user` field takes a team member on `POST /contacts` or `POST /companies` (email or `usr_` id), as in the app. **Read it back.** The response carries the field. A `GET /fields` sent right after may take a moment to list it. Renaming or removing an option, and converting a type, rewrite every contact or company of the team holding a value, within the call. requestBody: required: true content: application/json: schema: type: object required: - entity - name - type properties: entity: type: string enum: - contact - company description: Entity the field belongs to. name: type: string pattern: ^[a-z][a-zA-Z0-9]*$ maxLength: 400 description: >- Key to write the field with on `POST /contacts` or `POST /companies`. Starts with a lowercase letter, followed by letters and digits only. Identifies the field to update; never changes afterwards. type: type: string enum: - text - multilineText - number - date - select - boolean - phone - user - url description: >- Field data type. On an existing field, only `text` or `multilineText` may differ from the stored type (a conversion), and a `phone` or `user` field keeps its type. label: type: string maxLength: 400 description: >- Display name of the field, as shown in lemlist. Cannot contain an HTML tag (`<...>`). Optional: defaults to `name` on creation, unchanged when omitted on an update. upsertOptions: type: array items: type: string description: >- Select fields only. On creation, the options (at least one). On an update, options to add when missing; the present ones and the others are kept, so the same list replays. Distinct and non-empty; compared as in the app, regardless of case and surrounding spaces (`gold` matches an existing `Gold`), and stored without surrounding spaces. renameOptions: type: object additionalProperties: type: string description: >- Select fields only, on an update: `{ "current value": "new value" }`. The option keeps its identity, so the contacts or companies holding the current value are rewritten to the new one. removeOptions: type: array items: type: string description: >- Select fields only, on an update: options to drop. The contacts or companies holding one are cleared. At least one option must remain. examples: create-number: summary: create a number field value: entity: contact name: annualRevenue label: Annual revenue type: number create-select: summary: create a select field value: entity: contact name: tier label: Tier type: select upsertOptions: - Gold - Silver - Bronze update-select-options: summary: rename, remove and add options of an existing select value: entity: contact name: tier type: select upsertOptions: - Iron renameOptions: Gold: Platinum removeOptions: - Bronze convert-to-text: summary: convert an existing field to text value: entity: contact name: tier type: text responses: '200': description: Field updated (or unchanged, on a replay) content: application/json: schema: type: object properties: success: type: boolean data: type: object properties: entity: type: string enum: - contact - company description: Entity the field belongs to name: type: string description: >- Key to write the field with on `POST /contacts` or `POST /companies` label: type: string description: Human-readable display name type: type: string enum: - text - multilineText - number - date - select - boolean - phone - user - url description: Field data type source: type: string enum: - custom description: Always `custom` options: type: array items: type: string description: >- The options of a `select` field, in order (select fields only) created: type: boolean description: '`true` when the call created the field' updated: type: boolean description: >- `true` when the call changed an existing field; `false` on a replay that changed nothing changes: type: array items: type: string enum: - label - type - options description: What the call changed on an existing field required: - entity - name - label - type - source - created - updated - changes example: success: true data: entity: contact name: tier label: Tier type: select source: custom options: - Platinum - Silver - Iron created: false updated: true changes: - options '201': description: Field created content: application/json: schema: type: object properties: success: type: boolean data: type: object properties: entity: type: string enum: - contact - company description: Entity the field belongs to name: type: string description: >- Key to write the field with on `POST /contacts` or `POST /companies` label: type: string description: Human-readable display name type: type: string enum: - text - multilineText - number - date - select - boolean - phone - user - url description: Field data type source: type: string enum: - custom description: Always `custom` options: type: array items: type: string description: >- The options of a `select` field, in order (select fields only) created: type: boolean description: '`true` when the call created the field' updated: type: boolean description: >- `true` when the call changed an existing field; `false` on a replay that changed nothing changes: type: array items: type: string enum: - label - type - options description: What the call changed on an existing field required: - entity - name - label - type - source - created - updated - changes example: success: true data: entity: contact name: annualRevenue label: Annual revenue type: number source: custom created: true updated: false changes: [] '400': description: >- The body is refused. `error.code` names the case, `error.message` explains it. content: application/json: schema: type: object properties: success: type: boolean error: type: object properties: code: type: string description: >- Error code: `INVALID_ENTITY_PARAM`, `INVALID_TYPE_PARAM`, `INVALID_LABEL`, `INVALID_NAME`, `OPTIONS_NOT_ALLOWED`, `INVALID_OPTIONS`, `OPTION_NOT_FOUND`, `OPTION_ALREADY_EXISTS`, `FIELD_NAME_RESERVED`, `CONTACT_FIELD_COMPANY_PREFIXED`, `TYPE_CHANGE_NOT_ALLOWED`. message: type: string examples: invalid-entity-param: summary: '`entity` missing or not contact / company' value: success: false error: code: INVALID_ENTITY_PARAM message: Invalid entity parameter. Must be "contact" or "company" invalid-type-param: summary: '`type` missing or unknown' value: success: false error: code: INVALID_TYPE_PARAM message: >- Invalid type parameter. Must be one of: text, multilineText, number, date, select, boolean, phone, user, url invalid-label: summary: '`label` empty, too long or holding a tag' value: success: false error: code: INVALID_LABEL message: >- Invalid label. Must be a non-empty string of at most 400 characters, without a "<...>" tag invalid-name: summary: '`name` missing or off the pattern' value: success: false error: code: INVALID_NAME message: >- Invalid name. Must start with a lowercase letter followed by letters and digits only, at most 400 characters options-not-allowed: summary: option operations sent for another type than select value: success: false error: code: OPTIONS_NOT_ALLOWED message: >- Option operations (upsertOptions, renameOptions, removeOptions) apply to a select field only invalid-options: summary: option operations malformed, or no option left value: success: false error: code: INVALID_OPTIONS message: >- Invalid options. Expected non-empty strings of at most 400 characters, without a "<...>" tag, distinct regardless of case and surrounding spaces; a select keeps at least one option option-not-found: summary: >- a rename source or a removal names an option the field does not have value: success: false error: code: OPTION_NOT_FOUND message: Option "Bronze" does not exist on this field option-already-exists: summary: a rename target is already an option value: success: false error: code: OPTION_ALREADY_EXISTS message: Option "Silver" already exists on this field field-name-reserved: summary: name of a default or system field value: success: false error: code: FIELD_NAME_RESERVED message: This name is reserved for a default or system field contact-field-company-prefixed: summary: contact field name starting with company value: success: false error: code: CONTACT_FIELD_COMPANY_PREFIXED message: >- A contact field name cannot start with "company": that prefix is reserved for company data on import type-change-not-allowed: summary: a conversion the app does not offer value: success: false error: code: TYPE_CHANGE_NOT_ALLOWED message: >- A field can only be converted to text or multilineText, and a phone or user field keeps its type '401': description: Unauthorized content: application/json: schema: type: object properties: error: type: string example: error: Unauthorized '403': description: >- The API key user lacks the "Update contact & companies fields" permission, needed to update or delete a field (creating one needs none, as in the app). content: application/json: schema: type: object properties: success: type: boolean error: type: object properties: code: type: string description: 'Error code: `FIELD_PERMISSION_DENIED`.' message: type: string example: success: false error: code: FIELD_PERMISSION_DENIED message: >- The API key user is not allowed to update or delete custom fields (permission "Update contact & companies fields") '409': description: >- Another request changed the options of this field between the read and the write; nothing was written. Read the field again and replay the call. content: application/json: schema: type: object properties: success: type: boolean error: type: object properties: code: type: string description: 'Error code: `FIELD_CHANGED_RETRY`.' message: type: string example: success: false error: code: FIELD_CHANGED_RETRY message: >- The field options were modified by another request meanwhile: read the field again and replay your call components: securitySchemes: basicAuth: type: http scheme: basic ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.