> ## 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. > Lists all available fields for contacts and companies. # List Fields Returns all available fields for contacts and companies, grouped by entity. Use this endpoint to discover field names before upserting contacts or companies. ## Field sources | Source | Description | | ------------ | ------------------------------------------------------------------------- | | `default` | Built-in fields available on every account (e.g. email, firstName, phone) | | `custom` | Custom fields created by your team | | `crm_synced` | Fields from your connected CRM's field mapping configuration | ## CRM-synced fields When your team has a CRM connected, fields with `source: "crm_synced"` reflect the field mapping configured between lemlist and your CRM. These fields include an additional `crmField` property containing the corresponding field name on the CRM side. If no CRM is connected, no `crm_synced` fields are returned. ## Filtering Use query parameters to narrow results: * **`entity`** — return fields for a single entity (`contact` or `company`) * **`source`** — return only fields from a specific source (`default`, `custom`, or `crm_synced`) Both filters can be combined. ## OpenAPI ````yaml get /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: [] paths: /fields: get: tags: - Fields summary: List Fields parameters: - name: entity in: query required: false description: Filter by entity type schema: type: string enum: - contact - company - name: source in: query required: false description: Filter by field source schema: type: string enum: - default - custom - crm_synced responses: '200': description: Success content: application/json: schema: type: object properties: success: type: boolean data: type: object properties: contact: type: array items: type: object properties: name: type: string description: >- Internal field name (use this as the key when upserting contacts/companies) label: type: string description: Human-readable display name type: type: string enum: - text - number - boolean - datetime - date - phone description: Field data type source: type: string enum: - default - custom - crm_synced description: Origin of the field crmField: type: string description: >- Corresponding CRM field name (crm_synced fields only) required: - name - label - type - source company: type: array items: type: object properties: name: type: string description: >- Internal field name (use this as the key when upserting contacts/companies) label: type: string description: Human-readable display name type: type: string enum: - text - number - boolean - datetime - date - phone description: Field data type source: type: string enum: - default - custom - crm_synced description: Origin of the field crmField: type: string description: >- Corresponding CRM field name (crm_synced fields only) required: - name - label - type - source example: success: true data: contact: - name: email label: Email type: text source: default - name: firstName label: First name type: text source: default - name: revenue label: Annual Revenue type: number source: custom - name: leadStatus label: leadStatus type: text source: crm_synced crmField: hs_lead_status company: - name: linkedinUrl label: LinkedIn URL type: text source: default - name: industry label: Industry type: text source: custom '400': description: Bad request content: application/json: schema: type: object properties: success: type: boolean error: type: string example: success: false error: 'Invalid entity parameter. Must be one of: contact, company' '401': description: Unauthorized content: application/json: schema: type: object properties: error: type: string example: error: Unauthorized '405': description: Method not allowed content: application/json: schema: type: object properties: success: type: boolean error: type: string example: success: false error: Method not allowed. Use GET. components: securitySchemes: basicAuth: type: http scheme: basic ````