Keep your Kit subscribers clean and deliverable
Kit (formerly ConvertKit) automatically stops mailing addresses that hard-bounce, and it files away everyone who unsubscribes or complains - but it can't judge an address it has never sent to, and those never-mailed invalids are what quietly erode your deliverability while sitting on your invoice. Qualisend closes that gap: connect Kit, verify all your subscribers or those with a tag, then use the results to unsubscribe the dead ones so junk never reaches a broadcast. Here's how the native connector works, plus the CSV, API, and no-code options.
Connect Kit directly, no CSV needed
All you need is an API key
Paste your Kit API key. Find it in Kit under Settings → Advanced → API.
- Clean all subscribers or those with a tag
- Results saved as custom fields on each subscriber
- New subscribers checked in real time via webhook
- Auto-clean every 7, 14 or 30 days
Prefer CSV or the API? Both work too, see below.
What Kit cleans for you
Kit's native hygiene is reactive and solid: an address that hard-bounces is marked bounced, a subscriber who reports you is marked complained, and anyone who opts out is dropped - all three are excluded from every future broadcast and sequence with no action from you. Better still, none of those states count toward your bill, because Kit prices on active subscriber count and bounced, complained, and unsubscribed subscribers aren't active. For addresses Kit has actually mailed, that's reliable automatic hygiene.
What it can't catch
The catch is that every one of those mechanisms needs a send, a bounce, or a complaint to fire. Never-mailed invalids from imports and lead-magnet forms, disposable inboxes handed over for a free download, role addresses (info@, support@), and decayed mailboxes that will bounce next month all look identical to a healthy subscriber in Kit today. Imports are the sharpest case: a list that lived in another tool arrives with its bounce history amputated, so addresses that were already failing come into Kit looking brand new - and Kit will happily mail all of them once, which is exactly when a mailbox provider forms its first impression of you as a sender.
Why a clean Kit list matters
On Kit the stakes are double, because Kit bills on your active subscriber count. Every dead address is a line item on your invoice as well as a drag on deliverability. The category that hurts most is the cold subscriber - someone who hasn't opened or clicked in roughly 90 days: unlike a bounced address, a cold one is still active, so it counts toward the tier you pay for while pulling down the open and click rates Kit's reputation model, and Gmail and Yahoo's 2024 sender rules, judge you on. Cleaning before a broadcast does two jobs at once: unsubscribing the addresses you'll never reach again can move you under a pricing tier, and it protects the inbox placement of the sends that actually convert.
Prefer CSV or the API? Here's the manual path
The native connector is the fastest route, but the CSV loop works on any Kit plan: export from Kit, verify in Qualisend, and act on the results.
Export your subscribers from Kit
Open Grow → Subscribers, apply the filter, tag, or segment you want to clean (the full list for a first pass, or a cold or imported segment for maintenance), then choose Export - Kit emails you the CSV.
Verify the file in Qualisend
Upload the CSV to Qualisend bulk cleaning - up to 1,000,000 addresses per job, duplicates charged once - or paste addresses directly. The free plan's 100 credits, which never expire, cover a first sample.
Read the results
Every address returns deliverable, risky, undeliverable, or unknown with a reason code, a 0-100 score, and sub-flags (catch-all, disposable, role, full mailbox), plus the domain's MX provider and probe detail as evidence. Download the cleaned CSV with the verdict columns included.
Unsubscribe the dead addresses in Kit
Kit has no import-to-suppression list, so the clean way to retire an address is to unsubscribe it. Filter your results file to the undeliverables, tag the matching subscribers in Kit so the selection is reliable, bulk-select them, and choose Unsubscribe. Unsubscribing removes them from every send and from your active count without erasing the record - so a future import can't silently re-add a known-bad address.
Or automate it at signup
Prefer to keep junk out from the start? Verify at the point of capture with the Qualisend REST API (scoped keys, rate limits, webhooks), or wire a no-code flow through Zapier, Make, or n8n so a new Kit signup is checked before it's ever added - keeping typos and disposable addresses out of your active count from day one.
What Qualisend flags on every address
- Never-mailed invalid addresses that would hard-bounce on your next broadcast
- Disposable / throwaway inboxes handed over for a lead magnet and built to expire
- Role addresses (info@, support@) that skew engagement-judged sequences
- Catch-all domains, flagged so you can tag them into a segment and throttle sends
- A 0-100 confidence score and machine-readable reason code for every address
The native Kit connector is live. Connect it in Qualisend under Integrations and work with your Kit list directly, no CSV needed.
What to do with each result
Every address comes back with a verdict and sub-flags. Here's the action that keeps your Kit list clean without throwing away contacts you can still reach.
deliverableKeep sending as normal.deliverable + role flagKeep for transactional and newsletter content; exclude from engagement-judged sequences.risky + catch-all flagTag into a dedicated segment and throttle your sends.risky + disposable flagUnsubscribe - the inbox was built to expire.risky + full-mailbox flagPause sends and re-verify on your next clean - full mailboxes often recover.unknownLeave active and re-verify next clean - usually greylisting, not a verdict on the mailbox.undeliverableUnsubscribe via the bulk action; don't wait for the bounce to prove it.Related reading
The full step-by-step: export from Grow → Subscribers, verify, and unsubscribe the dead addresses.
Cleaning is half of deliverability - authenticate your Kit sending domain too.
Verify at signup so junk never enters your subscriber count.
How fast a dirty list compounds into a deliverability problem.
Set a cadence sized to how your Kit list grows, with bounce rate as the tripwire.
The full picture beyond list hygiene.
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