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Integration

Verify your SparkPost audience before you send

SparkPost suppression lists only stop mail after a bounce, complaint, or manual block has already registered against your sending domain. Pulling a stored recipient list, verifying it with Bounceless, and re-importing send-decision addresses catches dead mailboxes while they are still JSON or CSV rows, not permanent suppression entries you have to page through later.

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How it works

[01]Pull your SparkPost recipient listUse the SparkPost Recipient Lists API: GET /api/v1/recipient-lists/{id}?show_recipients=true with your API key in the Authorization header. The response includes every recipient address in the stored list as JSON — convert to CSV if you prefer spreadsheet review before upload to Bounceless.
[02]Verify the list in BouncelessUpload the member list to Bounceless as a bulk verification job. Each address gets a confidence level, reason codes, and a Pre-Send Decision: send, review, or suppress.
[03]Download the verified resultsWhen the job completes, download the results and keep only send-decision rows for re-import. Exclude suppress-decision addresses so they never rejoin the recipient list before your next transmission.
[04]Bulk re-import the clean listUpload send-decision addresses back to SparkPost with PUT /api/v1/recipient-lists/{id}, including the full recipients array SparkPost requires on update — the API replaces the list when recipients are supplied, so include all retained members, not just the changed rows.

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

When to run it

Pre-transmission list cleaningPull a stored list with show_recipients=true, verify it in Bounceless, and PUT the cleaned recipients array back before scheduling a transmission so invalid rows never reach SparkPost SMTP attempt loop.
Keeping the suppression list smallSparkPost suppression entries persist until removed. Verifying before send means fewer addresses ever generate bounces that land in the downloadable suppression list documented in SparkPost tech resources.
CRM or partner CSV onboardingVerify a partner export in Bounceless before creating or updating a SparkPost recipient list via the API, instead of discovering invalid rows through post-send bounce webhooks.

Common questions

Does this integration require SparkPost API access?

Yes. SparkPost recipient lists are managed through the REST API — there is no documented one-click CSV export in the dashboard for stored lists. Reading members and updating a list both require an API key with recipient-list scope. Verification itself happens entirely inside Bounceless once you produce the member file.

How is this different from SparkPost suppression list?

SparkPost suppression list is a reactive safety net: addresses appear there after bounces or complaints. Bounceless verifies before you transmit, reducing how many addresses ever generate a suppression entry. You can still export suppressions separately and audit them, but pre-send verification shrinks that downstream cleanup work.

Why does re-import require the full recipients array?

SparkPost documents that supplying recipients on PUT replaces the current list membership. That means your re-import payload must include every address you intend to keep, not only newly verified rows. Merge send-decision results with any existing members you are retaining before calling the update endpoint.

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

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