Official vendor OpenAPI document · agent-readyCommunicationsEmail 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.
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.
Install Jentic One Beta
Connect the Nylas API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Nylas API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fnylas.com%2Fnylas" | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL "https://jentic.com/install.sh?src=apis&api=%2Fapis%2Fnylas.com%2Fnylas" | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Nylas 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
Manage contact records, including create, update, and delete operations
Configure connectors that map a Nylas application to Google, Microsoft, or IMAP backends
Use Cases
Patterns agents use Nylas 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
Jentic AI Readiness Score
This API is usable in Jentic One now. Its AI-readiness score against Jentic's framework shows where it stands today and where improvements would make it even easier for agents to use.
N
Nylas API
- AI-Aware (B+)68/100
99
Foundational Compliance63
Developer Experience & Jentic Compatibility53
AI-Readiness & Agent Experience93
Agent Usability60
Security64
AI DiscoverabilityPowered by JenticScoring Framework 1.0.0 | Scoring Engine 0.4.0
Show dimension breakdown
99
Foundational Compliance
Base layer of spec validity and structural soundness.
Grade: A+Signals: 4
97%
Lint Results
Aggregated quality score from linter diagnostics, weighted by severity.
100%
Resolution Completeness
Percentage of `$ref` references that resolve successfully.
100%
Specification Validity
Checks whether the API description parses successfully and conforms to its declared specification (e.g., OpenAPI).
100%
Structural Integrity
Structural correctness score based on schema issues using logarithmic dampening.
63
Developer Experience & Jentic Compatibility
Clarity, completeness, and ingestion readiness for developers and tooling.
Grade: B-Signals: 4
0%
Example Density
How richly the API is illustrated with examples.
100%
Example Validity
Percentage of examples that conform to their schemas.
50%
Response Coverage
Percentage of operations with complete response definitions (success, client error, server error).
100%
Tooling Readiness
Health of API ingestion, bundling, and resolution within Jentic pipelines.
53
AI-Readiness & Agent Experience
Semantic breadth, depth, and agent comprehension for AI systems.
Grade: CSignals: 4
48%
Description Coverage
Coverage of descriptions across API elements.
0%
Error Standardization
Coverage of RFC 9457 Problem Details for error responses.
100%
OperationId Quality
Coverage, uniqueness, and casing consistency of operationIds for AI inference.
65%
Summary Coverage
Coverage of summaries across operations/tags/info.
93
Agent Usability
Functional utility, complexity comfort, and AI orchestration readiness.
Grade: A+Signals: 1
93%
Complexity Comfort
Agent comfort level based on API operational and structural complexity.
60
Security
Trust, risk posture, and security compliance.
Grade: B-Signals: 1
60%
Authentication Strength
Average quality of security schemes based on authentication method strength (weakest link for OAuth2).
64
AI Discoverability
Findability, semantic richness, and reasoning readiness.
Grade: BSignals: 1
64%
Descriptive Richness
Clarity and depth of descriptions across API elements.
Score it yourself
Every API in the directory is allowlisted, so you can re-score it with no key required.
npx @jentic/api-scorecard-cli score <openapi-url>Why Jentic?
What agents get from Jentic-routed access to this vendor.
Setup
Wiring Nylas by hand means setting up its bearer token auth, choosing the right US or EU host, and managing per-user grant tokens yourself. Through Jentic you install once, import Nylas from the API Directory, store the API key once, and your agent calls it.
Permission scoping
Nylas puts the grant id in the URL path (/v3/grants/{grantId}), so a rule can pin your agent to the operations it needs on those grants: it can authenticate connections and read grants while a destructive operation like grant deletion is not included unless you add it. You choose the operations it may call.
Credential isolation
Your Nylas API key and per-user grant tokens are stored once, encrypted, by your own Jentic One instance and injected at execution time. They never enter the agent's prompt, logs, or context.
Intent-based discovery
Agents search Jentic by intent such as 'send an email from a user mailbox' or 'create a calendar event', and Jentic returns the matching Nylas operation with its input schema so the agent calls the right endpoint without browsing the reference docs.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Nylas 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. Run it through Jentic One, the self-hosted execution layer, to get an agent API 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.
Can I limit what my agent is allowed to do with the Nylas API?
Yes. Because you run Jentic One yourself, your own rules decide which Nylas operations and which credentials the agent may use at execution time. Since Nylas puts the grant id in the URL path (/v3/grants/{grantId}), you can pin the agent to just the operations it needs, for example authenticating connections and reading grants, messages, and events, while a destructive call like grant deletion stays out of reach unless you explicitly add it. You choose the exact set of operations the agent can call.
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