james@contoso.comMicrosoft account, 4 areas
InboxGET /v1/email/threads
Lena Fischer10:42
Demo on Thursday?Is the 2 pm slot still free?
Thu, 14 Jan
09:30
Team standupTeams
FilesGET /v1/files
Q4 report.pdfUploaded via API, 2.4 MB

Outlook, Calendar and OneDrive API for your users' Microsoft accounts

Connect a Microsoft 365 account once and read and send Outlook mail, manage Outlook Calendar events with Teams links, upload to OneDrive and sync Outlook Contacts through one REST API, with webhooks for every change.

Start for freeView API docs
  • Outlook
  • Outlook Calendar
  • OneDrive
  • Outlook Contacts

Join 200,000+ of the world's most ambitious developers and builders

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How It Works

Three steps to a connected Microsoft account

1

Microsoft

Outlook

Outlook Calendar

OneDrive

Connect the account

Call GET /v1/connect/microsoft with the areas you need and send the user to Microsoft's consent screen.

2

POST /v1/email/messages

curl -X POST "https://zernio.com/api/v1/email/messages" \
  -H "Authorization: Bearer $ZERNIO_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "accountId": "acc_xxx",
    "to": [{ "email": "lena@northwind.io", "name": "Lena" }],
    "subject": "Your demo on Thursday",
    "text": "Hi Lena, see you Thursday at 2 pm."
  }'

Call one API

Send mail, create events and upload files with the same requests you use for Google accounts.

3

file.created

Q4 report.pdf in OneDrive

Delivered

calendar.event.created

Demo with Northwind

Delivered

message.received

Lena Fischer in Outlook

Delivered

Get webhooks

New mail, calendar changes and file changes arrive as webhooks, no Graph subscriptions to renew.

When a tenant only lets administrators approve apps, calls answer 412 admin_consent_required with an adminConsentUrl to hand to an admin

Features

Everything you need to ship Microsoft features

OneDrive

List, search, upload, rename, move, download and share files and folders in the user's OneDrive.

Outlook Contacts

The account's contacts sync into Zernio contacts, matched by email, with contact.updated and contact.deleted webhooks.

Outlook mail

List and search threads, read messages and attachments, send, reply and reply all, flag, mark read and move between folders.

Outlook Calendar

List calendars and events, create events with a Teams meeting, update, delete and RSVP. Free/busy and open slots across up to 10 accounts.

One inbox

Inbound Outlook mail lands in Zernio's unified inbox next to WhatsApp, Instagram and SMS, and fires message.received.

Only what you ask for

Each connection asks for the Graph permissions behind the areas you pass in scopes, and nothing more.

Integrate

Three ways in. Same API behind all of them

Write it yourself with the SDKs, hand it to an agent over MCP, or run it from a shell.

Read the docs
curl "https://zernio.com/api/v1/connect/microsoft?profileId=prof_xxx&scopes=email,calendar,files,contacts" \
-H "Authorization: Bearer $ZERNIO_API_KEY"
API reference
Supported Platforms

One integration
for Google and Microsoft accounts

Frequently Asked Questions

Learn more

Microsoft docs

Connect an account and call each area

Email API

One API for Gmail and Outlook

Files API

Google Drive and OneDrive

Ship Microsoft today

Connect a Microsoft account and ship Outlook, Calendar and OneDrive features this week.

Start for free
  • SOC 2
  • GDPR compliant
  • 99.97% uptime
  • Under 50ms response