How Nylas Syncs Customer Data
When an account is connected to Nylas, the sync engine starts pulling all mail for the account, prioritizing recent messages.
Mail isn't always added in reverse chronological order.
As new email arrives in the user's mailbox, it is also added in parallel. Click to see an overview of How Nylas Works.
Contacts and events are downloaded from newest to oldest. New events or contacts added after the sync start are not downloaded until the initial sync is complete.
Nylas stores raw MIME messages for 7 days. If you query within those 7 days, we'll return the message. If the message is deleted, we'll query it directly from the provider and re-fetch the message.
Nylas uses the following ways to keep your data in sync with the provider:
- Keeping an IMAP IDLE connection open
- Exchange ActiveSync's ping notifications
- Webhooks from calendar providers
- Polling the provider
When syncing transactional emails, such as Sendgrid or Mailgun, Nylas saves a copy on the IMAP server. This means your customer will also see the emails appear in their email provider account.