Connect your emailmaria@icloud.com
iCloud needs an app-specific passwordApple Account, Sign-In and Security, App-Specific Passwords
••••-••••-••••-••••
  • Found iCloud Mail settings
  • Signed in to IMAP
  • Signed in to SMTP
  • Found Sent and Drafts

Add any IMAP mailbox to your app today

iCloud, Yahoo, AOL, Fastmail, GMX, Zoho, Yandex or a company's own domain, on the same Email API as Gmail and Outlook. Your users type their email address and Zernio finds the server settings.

Start for freeView API docs
  • Any IMAP mailbox
  • App-password guidance
  • Scheduled send
  • Open and click tracking

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

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How It Works

Three steps to a connected mailbox

1

Email

iCloud, Yahoo, GMX

Gmail

Outlook

Your user types their email

One hosted link finds the server settings. Gmail and Microsoft addresses go to their own sign-in; everyone else gets their provider's app-password steps.

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."
  }'

You call one API

Send, read and reply with the same requests you use for Gmail and Outlook.

3

account.connected

maria@icloud.com

Delivered

email.opened

Your demo on Thursday

Delivered

message.received

Lena Fischer in iCloud Mail

Delivered

Changes come to you

New mail, opens, clicks, replies and bounces arrive as webhooks, and so does a mailbox that needs reconnecting.

Features

What can your app do with a connected IMAP mailbox?

Email-first connect

Settings come from presets, MX, autoconfig and Thunderbird's database. Errors name the step that failed, in plain words.

Drafts and scheduled send

Drafts live in the user's own Drafts folder, versioned so a person approves exactly one. Send up to 30 days later.

Read and send

List, search, read, send, reply, forward, move and trash, from the user's own address. Sent mail is filed in their Sent folder.

Health and reconnect

Passwords are stored encrypted. When one stops working, you get account.disconnected with a reconnect link that asks only for the new password.

Tracking and bounces

Open, click and reply tracking, and an email.bounced webhook with a recommended action.

Aliases and signatures

Send from addresses you declare for the mailbox, with a signature stored in Zernio.

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/email?profileId=prof_xxx&redirect_url=https://example.com/done" \
-H "Authorization: Bearer $ZERNIO_API_KEY"
API reference
Supported Platforms

One Email API
for Gmail, Outlook and IMAP mailboxes

Frequently Asked Questions

Learn more

IMAP docs

Connect, send, webhooks and limits

Email API

One API for Gmail, Outlook and IMAP

Inbox API

Email next to DMs and comments

Ship IMAP mailboxes today

Connect a mailbox, send the first email and get a webhook for every reply.

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