Migrating from another provider

Moving to BlacklistGuard from SendGrid, Mailgun, Postmark, or another provider is mostly a matter of re-authenticating your domain and pointing your app at the new API. The one thing not to skip: carry your suppression list across, so you don't email people who already complained or bounced.

Add the domain you'll send from and publish its DNS records — SPF, DKIM (generated for you), and DMARC. Follow Set up a sending domain. You can do this while your old provider is still sending; nothing breaks until you switch traffic over.

Generate an API key for your integration. You'll use it in the X-API-Key header.

This is the most important step for protecting your reputation. Export your suppressions — bounced, unsubscribed, and complained addresses — from your current provider, and import them into a suppression list on BlacklistGuard before you send anything. Emailing addresses that already bounced or complained elsewhere is the fastest way to start your new setup with a bad reputation.

Bring your audience over into mailing lists (CSV import or the API). Take the opportunity to clean the list — drop long-unengaged contacts and validate risky ones rather than carrying dead weight into your new sender reputation.

Point your application at the BlacklistGuard API. For transactional mail, that's a change to one request — see the Quickstart and the Send an email reference. Many teams run a small percentage of traffic through the new setup first, confirm it's landing, then move the rest.

If you're moving to a dedicated IP, it starts with no reputation — ramp volume gradually rather than cutting over all at once. See Warming up a dedicated IP. On the shared pool, there's nothing to warm.

For the first few weeks, watch delivery, bounces, and complaints daily (see Tracking delivery, bounces & complaints) and keep your old provider available as a fallback until you're confident. Once delivery is steady, complete the cutover.