Nylas

Nylas Transactional send API

Nylas' Transactional Send endpoint lets you send messages directly from an email domain that you've verified with Nylas. You can use this to send password reset emails, account verifications, or system notifications.

Documentation GitHub OpenAPI

Operations 1

POST /v3/domains/{domain_name}/messages/send Send a transactional email #

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-transactional-send-api"

All apis

curl "https://apis.io/api/v1/apis?limit=25"

Discovery needs no key. Ratings and market analysis are Pro.

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

openapi: 3.2.0
info:
  title: Nylas Transactional send 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.
  contact:
    url: https://www.nylas.com/
  x-provenance:
    method: harvested
    first_party: true
    publisher: Nylas
    source: https://developer.nylas.com/_spec-files/nylas-api.yaml
    harvested: '2026-08-21'
    sha256: 7ff001d571e163b1ffe22178741b59f813d8208ec878157a839a33dc2c13fd35
    bytes: 1666223
    note: 'Published by Nylas as the unified contract for the Nylas v3 API and stored verbatim; API Evangelist added only this provenance block. Submitted by the provider in api-evangelist/nylas#1 and verified against the live URL before harvest: OpenAPI 3.1.0, 118 paths, 208 operations, 174 component schemas, 100% of operations carrying summary, description, tag and a unique operationId, x-code-samples on 208 of 208. This document REPLACES a 22-operation scaffold API Evangelist derived from reading the documentation, now quarantined under openapi/_scaffold/.'
  x-evidence:
  - url: https://developer.nylas.com/_spec-files/nylas-api.yaml
    what: the published unified contract, harvested verbatim 2026-08-21 (200, text/yaml, 1,666,223 bytes)
  - url: https://developer.nylas.com/.well-known/api-catalog
    what: RFC 9727 linkset advertising that URL as service-desc for api.us.nylas.com and api.eu.nylas.com (200, application/linkset+json)
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 (37 KB total) ---
# Full source: https://raw.githubusercontent.com/api-evangelist/nylas/refs/heads/main/openapi/nylas-transactional-send-api-openapi.yml