Nylas API

Name: Nylas API API
Brand: Nylas API
Availability: InStock

✓ Official Vendor SpecCommunicationsEmail Deliverybearer55 EndpointsREST

For Agents

Read and write across users' email, calendars, and contacts on Google, Microsoft, and IMAP from a single unified API with bearer authentication and hosted auth.

Quickstart

Get started with Nylas API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"send an email from a user mailbox"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with Nylas API API.

Run a hosted OAuth-style flow that returns a long-lived grant for a user's mailbox

Send, list, and reply to email messages and manage drafts on the user's behalf

Create, update, and delete calendar events with attendee and recurrence handling

List the user's calendars and read free/busy availability for scheduling agents

GET STARTED

Start building with Nylas API API

Explore with Jentic

View OpenAPI Document

Use for: I need to send an email from a user's connected mailbox, Create a calendar event with two attendees and a Zoom link, List the user's upcoming meetings for tomorrow, Find a free 30-minute slot in the user's calendar this week

Not supported: Does not handle SMS, voice, push notifications, or marketing-grade email analytics — use for unified email, calendar, and contacts only.

The Nylas API v3 provides a unified communications surface across email, calendar, and contacts that abstracts away the differences between Google, Microsoft, and IMAP backends. The 55-endpoint API covers OAuth-style hosted authentication, grant management, connector configuration, and full read/write operations on messages, threads, drafts, events, calendars, and contacts. It is well suited to building scheduling tools, inbox-aware AI assistants, and CRM enrichment workflows that need to read and write across whichever email and calendar provider the end user happens to use.

Use Cases

Patterns agents use Nylas API API for, with concrete tasks.

★ AI Scheduling Assistant

Build a meeting-scheduling assistant that reads a user's calendar, proposes free slots, and creates events with the right attendees, regardless of whether the user is on Google or Microsoft. The unified events and grants endpoints mean one code path covers both backends, and the hosted auth flow handles consent. A working scheduling integration is achievable in 1-2 days from a fresh Nylas account.

GET /v3/grants/{grantId}/calendars/free-busy for the next five days, pick a 30-minute slot, then POST /v3/grants/{grantId}/events with the chosen time and attendees.

Inbox-Aware AI Assistant

Create an inbox copilot that summarises long threads, drafts replies, and triages on the user's behalf. Nylas exposes messages, threads, and drafts through a consistent shape, so an LLM-backed assistant can read context and write replies through the same interface across providers. This avoids maintaining separate Gmail and Microsoft Graph integrations.

List the user's unread messages via /v3/grants/{grantId}/messages, summarise the top thread, and create a draft reply via POST /v3/grants/{grantId}/drafts.

CRM Contact Enrichment

Sync a user's contacts and recent email correspondents into a CRM to keep records up to date without manual entry. Nylas's contact endpoints, combined with thread participants from the messages API, provide a richer signal than a contacts-only sync. This is a common pattern for sales-engagement tools and lightweight CRMs.

List contacts via /v3/grants/{grantId}/contacts and upsert each into the CRM, deduplicating on email address.

Agent-Driven Communication Across Providers

Let an AI agent send a message or schedule a meeting for a user without caring whether the underlying account is Google or Microsoft. Through Jentic, the agent searches by intent and gets only the operations it needs, with grant tokens held in the platform's vault rather than in the agent's context.

Search Jentic for 'send an email from a user mailbox', load the operation, and send a follow-up email referencing yesterday's meeting.

Key Endpoints

55 endpoints — the nylas api v3 provides a unified communications surface across email, calendar, and contacts that abstracts away the differences between google, microsoft, and imap backends.

METHOD

PATH

DESCRIPTION

POST

/v3/connect/auth

Start the hosted OAuth flow

POST

/v3/connect/token

Exchange the auth code for a grant token

GET

/v3/grants

List grants in a Nylas application

DELETE

/v3/grants/{grantId}

Revoke a grant

POST

/v3/connectors

Create a connector for a backend provider

POST

/v3/connect/auth

Start the hosted OAuth flow

POST

/v3/connect/token

Exchange the auth code for a grant token

GET

/v3/grants

List grants in a Nylas application

DELETE

/v3/grants/{grantId}

Revoke a grant

POST

/v3/connectors

Create a connector for a backend provider

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Nylas API keys and per-user grant tokens are stored encrypted in the Jentic vault. Agents receive scoped access — neither the API key nor any grant token enters the agent's context.

Intent-based discovery

Agents search Jentic with phrases like 'send an email from a user mailbox' or 'create a calendar event'. Jentic returns the matching operation and its input schema so the agent can call the correct endpoint without browsing the OpenAPI spec.

Time to first call

Direct integration: 3-5 days for hosted auth, grant handling, and per-resource testing across providers. Through Jentic: under an hour — search, load, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

Gmail API

Direct provider API for Gmail-only workloads, without the unified abstraction.

Choose Gmail directly when the application only needs to support Google accounts and you want the lowest abstraction.

Complementary

SendGrid Email Activity API

Pair with Nylas for transactional email tracking and analytics on outbound messages.

Use when outbound app-generated mail needs deliverability analytics that Nylas does not provide.

Complementary

Twilio API

Add SMS and voice channels alongside Nylas's email and calendar surface.

Use when the agent needs to fall back to SMS or voice if a user does not respond by email.

FAQs

Specific to using Nylas API API through Jentic.

What authentication does the Nylas API use?

Nylas uses bearer authentication. Application-level calls send your Nylas API key in the Authorization header; per-user calls send the grant token issued by the hosted auth flow at /v3/connect/auth and /v3/connect/token. Through Jentic, both keys and grant tokens are stored encrypted in the vault.

Does Nylas support Microsoft and Google in one API?

Yes — that is the core value. The same /v3/grants/{grantId}/messages, /events, and /contacts paths work across Google Workspace, Microsoft 365, and IMAP backends, with the difference handled by Nylas's connector layer.

What are the rate limits for the Nylas API?

The OpenAPI spec does not embed explicit limits. Nylas applies per-application and per-grant throttling that varies by plan; back off on HTTP 429 and the X-RateLimit-* response headers when present.

How do I send an email from a user's mailbox through Jentic?

Run pip install jentic, then search for 'send an email from a user mailbox'. Jentic returns the messages-send operation with its input schema; supply the grant id, recipients, subject, and body and execute. Sign up at https://app.jentic.com/sign-up to get an agent key.

Can I find a free time slot for a user?

Yes — the free/busy endpoints expose availability for the user's connected calendars across providers, so an agent can pick a slot before posting an event via POST /v3/grants/{grantId}/events.