Nylas

Nylas Messages API

Messages. List, search, read, update and delete email messages. Send immediately, schedule a send and cancel a scheduled send, with folders, signatures and attachments alongside.

GitHub OpenAPI

Operations 9

Each operation below carries the questions people ask an LLM about it and the instructions they give an agent to run it. Generated by API Evangelist overlay

GET /v3/grants/{grant_id}/messages List or search a user's email messages · Return all Messages #
Ask an LLM
“How do I list the emails in a connected user's mailbox?”
“Can I filter a user's messages to only unread ones that have attachments?”
Tell an agent
List the latest {limit} messages in mailbox {grant_id}.
Find messages in {grant_id} from {from} with the subject {subject}.
GET /v3/grants/{grant_id}/messages/{message_id} Retrieve a single email message · Return a Message #
Ask an LLM
“How can I fetch the full contents of one email by its message ID?”
“Can I get just the headers or selected fields of a single message?”
Tell an agent
Open message {message_id} in mailbox {grant_id}.
Fetch message {message_id} for grant {grant_id} including its {fields}.
PUT /v3/grants/{grant_id}/messages/{message_id} Mark, star or move an email message · Update message attributes #
Ask an LLM
“How do I mark an email as read or unread through the API?”
“Can I star a message or move it to another folder?”
Tell an agent
Mark message {message_id} in {grant_id} as unread.
Star message {message_id} for grant {grant_id}.
DELETE /v3/grants/{grant_id}/messages/{message_id} Delete an email message · Delete a message #
Ask an LLM
“Does deleting an email send it to Trash or remove it permanently?”
“How do I permanently delete an email instead of trashing it?”
Tell an agent destructive · confirm first
Delete message {message_id} from mailbox {grant_id}.
Hard delete email {message_id} for grant {grant_id} so it skips the Trash.
PUT /v3/grants/{grant_id}/messages/clean Clean up email bodies into plain content · Clean messages #
Ask an LLM
“Can I strip signatures, links and images out of email bodies to get clean text?”
“Is there a way to convert an email's HTML into Markdown?”
Tell an agent
Clean messages {message_id} in mailbox {grant_id} and return them as Markdown.
Clean email {message_id} for {grant_id}, removing links and images.
POST /v3/grants/{grant_id}/messages/send Send or schedule an email from a user's mailbox · Send a Message #
Ask an LLM
“How do I send an email on behalf of a connected user?”
“Can I schedule an email to go out at a later time?”
Tell an agent
Send an email from {grant_id} to {to} with subject {subject}.
Schedule a message from mailbox {grant_id} to {to} to be sent at {send_at}.
GET /v3/grants/{grant_id}/messages/schedules List a user's scheduled emails · Return scheduled messages #
Ask an LLM
“Which emails does this user have scheduled to send later?”
“Can I see scheduled messages that have already gone out as well as pending ones?”
Tell an agent
List all scheduled messages for mailbox {grant_id}.
Show me every send schedule on grant {grant_id}.
GET /v3/grants/{grant_id}/messages/schedules/{scheduleId} Check the status of one scheduled email · Return a scheduled message #
Ask an LLM
“How can I check whether a specific scheduled email has been sent yet?”
“Can I look up a single scheduled message by its schedule ID?”
Tell an agent
Get scheduled message {scheduleId} for mailbox {grant_id}.
Check the send status of schedule {scheduleId} on grant {grant_id}.
DELETE /v3/grants/{grant_id}/messages/schedules/{scheduleId} Cancel a scheduled email before it sends · Cancel a scheduled message #
Ask an LLM
“How do I stop a scheduled email from going out?”
“How close to the send time can I still cancel a scheduled message?”
Tell an agent destructive · confirm first
Cancel scheduled message {scheduleId} in mailbox {grant_id}.
Unschedule send {scheduleId} for grant {grant_id} so it never goes out.

Specifications

⚙
OpenAPI
https://artifacts.apis.io/nylas/openapi/nylas-messages-api-openapi.yml

Work with this as data

Every API here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for apis

7 MCP tools reach this
  • find_apisBrowse and filter every API in the catalog.
  • get_api_artifactsOne API's artifacts, grouped by type.
  • get_openapiThe primary OpenAPI for this API.
  • find_similar_apisAPIs that look like this one.
  • apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
  • resolveTurn a domain, URL or GitHub org into the provider it belongs to.
  • find_cohortsEvery scored population of providers in the catalog.
All 92 tools →

Call it yourself

curl for this page
This API 
curl "https://apis.io/api/v1/apis/nylas:nylas-messages-api"
All apis 
curl "https://apis.io/api/v1/apis?limit=25"

Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.

OpenAPI Specification

nylas-messages-api-openapi.yml Raw ↑ 
openapi: 3.2.0
info:
  title: Nylas Messages API
  version: v3
  summary: The complete Nylas v3 API — Email, Calendar, Contacts, Notetaker, Scheduling, Administration, and Migration.
  description: The Nylas API is designed using the REST ideology to provide simple and predictable URIs to access and modify objects. Requests support standard HTTP methods like `GET`, `PUT`, `POST`, and `DELETE`, and standard status codes. Response bodies are always UTF-8 encoded JSON objects, unless explicitly documented otherwise. You can use the Nylas Postman collection to quickly start using the Nylas APIs. For more information, check out the Nylas Postman collection documentation.
  contact:
    url: https://www.nylas.com/
servers:
- url: https://api.us.nylas.com
  description: U.S.
- url: https://api.eu.nylas.com
  description: E.U.
security:
- ACCESS_TOKEN: []
- NYLAS_API_KEY: []
tags:


# --- truncated at 32 KB (132 KB total) ---
# Full source: https://artifacts.apis.io/nylas/openapi/nylas-messages-api-openapi.yml