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Integration

Verify your Mailgun audience before you send

Mailgun's own Bounces, Unsubscribes, and Complaints tables only catch an address after it fails — a hard bounce, an unsubscribe click, a spam complaint, all discovered mid-send against your domain reputation. Running your mailing list through Bounceless first catches dead mailboxes and typos while they are still rows in a file, before Mailgun's own suppression system ever has to.

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How it works

[01]Pull your Mailgun mailing listMailing lists live under the Mailing Lists area of the Control Panel, or you can read them directly with the API: GET /v3/lists/{list_address}/members returns every member as JSON, with a paginated variant for larger lists.
[02]Verify the list in BouncelessUpload the exported member list to Bounceless as a bulk verification job. Every address gets a confidence level, reason codes, and a Pre-Send Decision: send, review, or suppress.
[03]Bulk re-import the clean list with upsertUpload the send-decision addresses back to the list with POST /v3/lists/{list_address}/members.csv (or the .json variant), up to 1000 members per call. Setting upsert=yes updates members who already exist instead of erroring on them.
[04]Fewer addresses reach the Bounces suppression tableMailgun stores hard-bounced addresses permanently in the Bounces table under the Suppressions tab and stops sending to them. Verifying before you send means fewer addresses ever land there in the first place, and your sender reputation stays cleaner from the start.

Steps are sourced from Mailgun's official documentation (reference) and have not yet been walked on a live Mailgun account by a Bounceless team member — treat exact menu labels as indicative until this note is removed.

When to run it

Pre-send cleaning of a mailing listPull members with the API, verify the file in Bounceless, then bulk re-import with upsert=yes so the invalid rows never rejoin the list before your next send.
Keeping the Bounces table smallMailgun only suppresses an address after it hard-bounces. Catching dead mailboxes in Bounceless first means fewer addresses ever hit that table, and cleaner deliverability from day one.
Importing a CRM or partner CSVVerify a partner or CRM export in Bounceless before bulk-uploading it into a Mailgun list, instead of finding the invalid rows later through bounces and complaints.

Common questions

Does this integration require Mailgun API access?

Yes, at least for the re-import step. Mailgun's public docs don't describe a one-click CSV export button for mailing lists, so pulling members and bulk re-uploading the cleaned file both go through the Mailgun API rather than a dashboard-only flow. The verification step itself happens entirely inside Bounceless.

How is this different from Mailgun's own Bounces table?

Mailgun's Bounces, Unsubscribes, and Complaints tables are suppression lists — they only stop future sends to an address after that address has already failed once. Bounceless verifies addresses before you send at all, so fewer of them ever generate a bounce or complaint for Mailgun to suppress in the first place.

Which Mailgun API key does this workflow need?

A domain sending key only covers sending messages and cannot manage lists or suppressions. Reading and re-importing mailing list members needs the primary account API key (or a suitably scoped key), which Mailgun's docs note is more powerful and should be stored in a secrets manager rather than committed to source control.

This guide covers running Bounceless alongside Mailgun. Weighing Bounceless against Mailgun's own validation tooling instead? See the Bounceless vs Mailgun comparison.

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