ConvertKit Email
Verification Integration
Connect your ConvertKit account to ValidEmailChecker and verify your subscriber lists without file exports, manual uploads, or spreadsheet juggling. Whether you are running a newsletter, selling digital products, or building your creator empire — keeping your ConvertKit list clean is essential for high deliverability and low bounce rates.
Connect ConvertKit
Enter your V4 API Key
Connection Name (optional)
ConvertKit V4 API Key
Where to find: Settings → Developer → V4 Keys (Beta) → Create or copy key starting with kit_
What You Need to Get Started
ConvertKit Account
Any plan — free tier included.
V4 API Key
Starts with kit_ — found in Developer settings.
Verification Credits
1 credit per email. 200 free on signup.
60 Seconds
Paste your key and you are connected.
ConvertKit V4 API Key — Important
ValidEmailChecker requires ConvertKit's newer V4 API Key. The older V3 key will not work.
V4 Key (Required)
V3 Key (Will Not Work)
How to find your V4 API Key:
Open Settings
Click the gear icon in the top-right corner of ConvertKit.
Go to Developer
Select Developer from the left sidebar under Settings.
Copy V4 Key
Look for V4 Keys (Beta). Click "Add a new key" if needed, then copy the key starting with kit_.
How to Connect ConvertKit
The entire setup takes under a minute. Here is exactly what to do.
Get Your V4 API Key
Log in to your ConvertKit account. Click the Settings gear icon in the top-right corner, then select Developer from the left sidebar. Scroll to the V4 Keys (Beta) section. If you do not have a key yet, click Add a new key. Copy the API Key that starts with kit_ — even a small typo will prevent the connection from working.
You will need:
V4 API Key
kit_a1b2c3d4e5f6g7h8i9j0...
Connect Your Account
In ValidEmailChecker, go to Integrations in the left sidebar and find ConvertKit in the Available Integrations section. Click the ConvertKit card, enter an optional connection name (like "My Creator Account" or "Newsletter Business"), paste your V4 API Key, and click Connect Account. We verify your key instantly and establish the connection. If you manage multiple ConvertKit accounts, you can connect them all — just give each a unique name.
Select a Form or Tag and Configure
Go to Bulk Upload, click Connect Email Platform, select your ConvertKit connection, and click Sync Now to fetch your latest forms and tags with subscriber counts. Select the form or tag you want to verify, then choose your mode: Verify Only to review results before making changes, or Clean Automatically to mark invalid and disposable subscribers as Cancelled directly in ConvertKit. You control exactly what happens to each email type.
Important: ConvertKit does not support hard deletion via API. Auto-cleaning marks contacts as "Cancelled" (unsubscribed). They will still appear in your account but will not receive emails. Start with "Verify Only" to review results first.
Track Results in Real Time
Click Import List and you will be redirected to the Uploads & Results page where you can watch progress in real time. No need to refresh — the page updates automatically. When complete, you get a full breakdown: safe, invalid, risky, disposable, catch-all, and more. Download results in CSV, XLSX, JSON, or TXT. If you chose automatic cleaning, the changes are already applied to your ConvertKit account.
Want a visual walkthrough with screenshots?
Our help center has the full step-by-step guide with images for every screen.
Two Ways to Verify
Verify Only
Import and verify your subscribers without modifying anything in ConvertKit. Review results, download reports, and decide what to do next — on your terms.
Best for:
Clean Automatically Recommended
Verify and clean in one step. Invalid and disposable subscribers are marked as Cancelled (unsubscribed) directly in ConvertKit — no manual work required.
Actions available:
Tracking Your Verification Progress
Once verification starts, you are automatically redirected to the Uploads & Results page where everything updates in real time — no refreshing needed.
What you will see for each task:
Task ID
Unique identifier for this verification
List Name
Your ConvertKit form or tag name
Upload Date
When verification started
Total Emails
Number of subscribers being verified
Status
Processing, Completed, Failed, etc.
Progress
Percentage complete with progress bar
Processing
Verification in progress
Completed
Click "View Results" to see breakdown
With Warning
Some emails could not be processed (credits refunded)
Failed
Something went wrong (rare)
Managing Your ConvertKit Connection
Connection Actions
Click the three-dot menu next to any connection on your Integrations page:
Sync Now
Fetch latest forms and tags from ConvertKit and start a new verification.
Rename
Change the connection display name — helpful for multiple accounts.
Delete
Remove this connection entirely. Does not affect your ConvertKit account.
Multiple Accounts
Manage multiple ConvertKit accounts for different businesses or clients.
Go to Bulk Upload → Connect Email Platform
Select ConvertKit and see existing connections
Click "+ Add Another Account"
Enter the new account's V4 API Key and give it a unique name
Name each connection clearly: "Newsletter Business," "Client — ABC Company," "Course Platform."
Credits & Billing
1 Credit = 1 Email
Same rate as all other verification methods.
Unknown = Refunded
Credits returned instantly for unverifiable emails.
Duplicates = Free
Removed before charging — you only pay for unique emails.
Connecting = Free
Syncing forms and tags never uses credits.
Credits Running Low?
If you do not have enough credits for your list size, you can purchase more credits instantly or set up auto-refill so you never run out during a critical verification.
Team Member Access
Team members can connect their own ConvertKit accounts and run verifications using the shared team credit balance. The account owner can see credits used by each team member in the transaction history.
Understanding ConvertKit's Unsubscribe Behavior
ConvertKit handles contact removal differently than most platforms. Here is what you need to know.
What "Remove" Actually Means
Why This Matters
Cleaning Up Cancelled Subscribers in ConvertKit
After ValidEmailChecker marks contacts as Cancelled, you can bulk delete them in ConvertKit to free up your subscriber limit:
Forms vs Tags in ConvertKit
Forms
Contain subscribers who signed up through that specific form — landing pages, inline forms, modal pop-ups, or embedded widgets.
Best for verifying:
Tags
Labels applied to subscribers regardless of how they joined. Tags let you segment your audience by interest, behavior, purchase history, or any custom grouping.
Best for verifying:
Troubleshooting
"Invalid API Key" Error
Make sure you are using a V4 API Key that starts with kit_. The older V3 API Key and API Secret will not work. Copy the key again from ConvertKit's Developer settings and check for extra spaces before or after the value. If the key was revoked in ConvertKit, generate a new one.
"No Forms or Tags Found"
Click Sync Now to refresh the list. Make sure you have at least one form or tag in ConvertKit with confirmed subscribers — empty forms and tags may not appear. Verify you are logged into the correct ConvertKit account and that your V4 API Key belongs to that account.
"Connection Failed" or "Unable to Connect"
Check your internet connection and try again. If the issue persists, generate a new V4 API Key in ConvertKit (Settings → Developer → V4 Keys). Clear your browser cache, disable browser extensions that might interfere, and try connecting again.
"0 Subscribers Imported"
Select a form or tag that has confirmed subscribers. Make sure you selected a specific form or tag (not the section header). Click Sync Now to refresh the subscriber list. If the issue persists, verify the form or tag has active subscribers in ConvertKit.
Verification Stuck at "Processing"
Large lists take longer — 100,000+ subscribers may take several minutes. The page auto-updates in real time so there is no need to refresh. If stuck for more than 30 minutes, contact support.
Auto-Clean Did Not Work
Check that you selected specific email types to remove and had "Clean list automatically" selected (not "Verify only"). Changes may take a few minutes to reflect in ConvertKit. Check your ConvertKit "Cancelled" subscribers list to confirm the changes were applied.
Best Practices for ConvertKit List Hygiene
Before Your First Verification
Ongoing List Hygiene
Recommended Actions
Frequently Asked Questions
Yes. The ConvertKit integration works with all ConvertKit plans, including the free tier. You just need access to your V4 API Key from the Developer settings page. Every ConvertKit account can generate a V4 key.
ValidEmailChecker uses ConvertKit's newer V4 API for better reliability and access to forms and tags. The older V3 API Key and API Secret won't work. V4 keys start with "kit_" and are found under Settings → Developer → V4 Keys (Beta).
Verifying alone does not change your subscriber count. If you enable auto-cleaning, contacts are marked as "Cancelled" (unsubscribed) — they still count toward your subscriber limit until you manually delete them from ConvertKit's dashboard.
Yes. When selecting what to verify, you can choose individual tags. This is useful for verifying specific segments like "Launch List" or "Paid Subscribers" without touching your entire subscriber database.
Forms contain subscribers who signed up through that specific form. Tags are labels you can apply to any subscriber regardless of how they joined. Both work with ValidEmailChecker — select whichever grouping you want to verify.
This is a ConvertKit API limitation, not a ValidEmailChecker one. ConvertKit's API only supports marking contacts as Cancelled (unsubscribed) — not permanent deletion. You can bulk delete cancelled subscribers manually from ConvertKit's dashboard to free up your subscriber limit.
For active newsletters and creator businesses, we recommend quarterly verification. Before major campaigns, product launches, or paid promotions, do an additional verification to ensure maximum deliverability. Email data decays at roughly 2% per month.
No. Once contacts are marked as Cancelled through auto-cleaning, you cannot restore them through ValidEmailChecker. You would need to manually re-add them in ConvertKit. This is why we strongly recommend starting with "Verify Only" mode to review results first.
Yes. If you deleted a connection, simply add it again using the same V4 API Key. Your previous verification history remains in ValidEmailChecker. If you regenerated your API key in ConvertKit, use the new key to reconnect.
No. Connecting and syncing your account is completely free. You only use credits when you actually verify emails — 1 credit per email, same as every other verification method. Duplicates are removed before charging.
Ready to Clean Your ConvertKit Lists?
Sign up, connect your ConvertKit account, and verify your first list in under two minutes. 200 free credits included — no credit card required.
Get Started Free200 free credits · No credit card · V4 API Key setup in 60 seconds