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Provider Setup

Herald talks to mail providers through IMAP for reading and SMTP for sending. Provider setup is mostly about supplying the correct host, port, username, password, and optional OAuth or bridge details.

Choose the narrowest stable path that matches your account. Personal Gmail users should prefer Gmail IMAP with an App Password; Proton Mail users should run Proton Mail Bridge and use Bridge-generated credentials; other providers can use standard IMAP/SMTP settings or a preset.

Provider pathIMAPSMTPCredential type
Gmail IMAPimap.gmail.com:993smtp.gmail.com:587Google App Password
Proton Mail Bridge127.0.0.1:1143127.0.0.1:1025Bridge-generated username and password
Fastmailimap.fastmail.com:993smtp.fastmail.com:587Provider password or app password
iCloudimap.mail.me.com:993smtp.mail.me.com:587App-specific password
Outlookoutlook.office365.com:993smtp.office365.com:587Provider-supported IMAP credential
Custom IMAPYour provider valueYour provider valueProvider-specific
  1. Enable 2-Step Verification on the Google account.
  2. Create a Google App Password.
  3. Run ./bin/herald.
  4. Choose Gmail (IMAP + App Password).
  5. Enter the Gmail address and App Password.
  6. Save the generated config and let Herald sync.
  1. Start Proton Mail Bridge locally.
  2. Copy the Bridge-generated IMAP and SMTP credentials.
  3. Choose the Proton Mail Bridge preset or enter the host and ports manually.
  4. Save and keep Bridge running while Herald is connected.
  1. Collect IMAP host/port and SMTP host/port from your provider.
  2. Choose standard IMAP in the wizard or edit YAML directly.
  3. Use provider-specific app passwords when required.
  4. Launch Herald with ./bin/herald -config path/to/conf.yaml.

Provider credentials live in the Herald config file. Herald opens an IMAP connection for the lifetime of the app, caches message metadata in SQLite, fetches body text when needed, and sends outgoing messages over SMTP.

If IMAP works but send fails, the SMTP section is wrong or the provider requires a separate app password. If the mailbox stays empty, verify the selected folder and check Sync and Status.