Mail for developers and CTOs
An email API for developers that connects your users’ real mailboxes
Gmail, Microsoft 365, Yahoo and IMAP behind one REST API and one webhook format.
Free tier on every product. No card.
curl -X POST https://api.syncyak.com/v3/grants/$GRANT_ID/messages/send \
-H "Authorization: Bearer $SYNCYAK_API_KEY" \
-H "Content-Type: application/json" \
-d '{"to":[{"email":"[email protected]"}],
"subject":"Saturday showing",
"body":"<p>See you at 10.</p>"}'An email API for developers usually means one of two things: sending bulk or transactional mail from your own domain, or working with your users’ own mailboxes. SyncYak Mail is the second kind. Users connect Gmail, Microsoft 365, Yahoo or any IMAP mailbox on a hosted page, and your app reads messages, sends from their address and receives webhooks for new mail, all through one REST API.
It speaks the Nylas v3 format, so existing client code and examples apply.
How it works
Add a mailbox API to your app in three steps
Register your apps
Create a Mail application and paste your Google and Microsoft OAuth client IDs and secrets, with the callback URI SyncYak shows.
Send users to the connect page
Link to /v3/connect/auth with your client ID and redirect URI. Users approve access; you get a code to exchange for a grant.
Read, send and listen
Call the /v3 API with the grant id and receive webhooks for new mail, replies, bounces, opens and clicks.
A unified email API across providers
The connect page detects the provider from the address (built-in table, MX records, Thunderbird’s ISP database, autoconfig) and offers OAuth or an app password. Every mailbox becomes a grant with the same API.
- OAuth with PKCE and single-use state
- App passwords tested against IMAP and SMTP before saving
- Grants revived with the same id when a user reconnects
Send email on behalf of users
Sending uses the provider’s own API or SMTP for that mailbox, so mail comes from the user’s address and lands in their Sent folder. From Hobby, open and click tracking adds events to your webhooks.
Use cases
What developers build
Inbox features in a SaaS
Threads, replies and sending inside your product.
Automated follow-up
Sequences that send from the user’s real address.
Email-driven workflows
A new email starts a job in your system.
What you get with Mail
Mail is a mailbox API that speaks the Nylas v3 format. You register your own Google, Microsoft and Yahoo OAuth apps once, send people to SyncYak’s hosted connect page, and get a grant per connected mailbox. IMAP and SMTP with an app password cover every other provider.
Free connects 3 mailboxes and sends 1,000 messages a month. Hobby is $12 a month for 10 mailboxes with open and click tracking; Pro is $49 for 50; Business is $199 for 250.
- Hosted connect page with provider detection, PKCE and single-use state
- Webhooks for message.created, replies, bounces, opens and clicks, signed with HMAC-SHA256
- POST /v3/grants/{grant_id}/messages/send sends from the user’s own address
- An existing Nylas v3 integration switches by changing the API host, client ID and secret
Frequently asked questions
Something else? Write to [email protected] and a person answers.
Is this for bulk marketing email?
No. It works with users’ own mailboxes. For bulk sending from your domain, use an email delivery service.
How are API calls authenticated?
With the application secret or an account API key as a Bearer token.
How many mailboxes can I connect?
Per plan, from three on Free; extra mailboxes are an add-on.
Is there a free plan for Mail?
Yes. Mail has a free tier with no card and no end date: 3 mailboxes, inbound webhooks, your own google and microsoft apps. Paid tiers start at $12 a month, and you can move up or down at any time.
Can I use the other SyncYak products on the same account?
Yes. Email parsing, the mailbox API, CRM sync, error tracking and tunnels share one login, one team, one API key system and one bill. Each product has its own tier, so you only pay more for the one that grows.
Related
Related solutions
Start with Mail free
3 mailboxes, Inbound webhooks, Your own Google and Microsoft apps, free every month. Set up in minutes, and add the other SyncYak products on the same account when you need them.
Free tier on every product. No card.