Nylas now allows legacy systems that speak only IMAP or SMTP to interact with the same mailbox that an AI agent accesses via REST API, eliminating the need to rewrite old tools. The feature, part of the Nylas Agent Account offering, exposes a single mailbox through both the v3 API and standard email protocols, with changes visible on both sides within seconds. This enables ticketing systems, backup scripts, monitoring tools, and compliance archivers to read and send mail without any HTTP integration.
How it works
An Agent Account is a Nylas-hosted mailbox that provides a grant_id usable with all existing grant-scoped endpoints—Messages, Drafts, Threads, Folders, and more. The IMAP/SMTP layer adds a second access door to the same backend storage, meaning there is no sync job or eventual-consistency window. Legacy tools authenticate with a username and password, while the agent continues to operate over REST for structured tasks like filtering, classifying, and replying in-thread.
To enable protocol access, users must set an app password on the grant. This password is separate from the API key and is required for any IMAP LOGIN or SMTP AUTH attempt. It must be 18-40 characters long, contain at least one uppercase letter, one lowercase letter, and one digit, and use only printable ASCII characters. Nylas stores it as a bcrypt hash, so it cannot be retrieved later—only reset.
Setting up the app password
The app password can be set at account creation via the CLI or API. For example, the CLI command `nylas agent account create support@yourcompany.com --name "Support Bot" --app-password "MySecureP4ssword2024"` creates the account and sets the password in one step. Over the API, the password is included in the `settings` object of the `POST /v3/connect/custom` call.
To rotate an existing password, use `nylas agent account update support@yourcompany.com --app-password "MyRotatedP4ssword2025"` or `PATCH /v3/grants/{grant_id}` with the full settings object. Rotation immediately disconnects all active IMAP and SMTP clients, which must reconnect with the new password. Nylas recommends planning rotations during quiet windows if legacy tools cannot gracefully re-authenticate.
Legacy tool integration
Once the app password is configured, any IMAP/SMTP client can connect using the account's email address as the username and the app password as the password. Desktop clients like Thunderbird, Apple Mail, or Outlook can be set up manually with Nylas's IMAP and SMTP server details for the appropriate region. Scripts and automation tools that send or poll mail via SMTP and IMAP also work without modification.
Nylas emphasizes that Agent Accounts are intended for mailboxes owned by the agent and its tooling—such as support@, notifications@, or intake@—not for human inboxes. For putting an agent on a real Gmail or Microsoft 365 account, a connected grant is the appropriate solution.
Prerequisites and considerations
To use this feature, you need a Nylas API key, a registered domain (custom or Nylas *.nylas.emailtrial subdomain), and an Agent Account with its grant_id. New domains undergo a warming period of roughly four weeks before achieving full sending reputation. Account creation via the API auto-generates a default workspace and policy; custom policies can be attached later.
The tradeoff is that the mailbox is Nylas-hosted, not your existing Google Workspace or Microsoft 365 account. However, it avoids the multi-week effort of standing up Dovecot, Postfix, and deliverability infrastructure. Nylas handles TLS, deliverability, and provides the API on top, with no OAuth token refresh issues since there is no upstream provider.