> ## 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. > Re-subscribes a contact, removing the do-not-contact flag. # Re-subscribe Contact ## OpenAPI ````yaml delete /v2/unsubscribes/contacts/{contactId} 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: /v2/unsubscribes/contacts/{contactId}: delete: tags: - Unsubscribes summary: Re-subscribe Contact description: Removes the unsubscribed (do-not-contact) flag from a contact. parameters: - name: contactId in: path required: true description: The contact identifier example: con_aB1cD2eF3gH4iJ5kL schema: type: string responses: '200': description: Success content: application/json: example: Contact subscription updated '400': description: Bad request content: text/plain: example: Bad contact identifier '401': description: Unauthorized '500': description: Server error content: text/plain: example: Failed to update contact subscription components: securitySchemes: basicAuth: type: http scheme: basic ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.