Guides
Platform-specific, because the thresholds, the warnings and the consequences are not the same in any two of them.
Clean a list for ActiveCampaign
ActiveCampaign bills by contact across every list, so a contact on three lists is billed once and an undeliverable contact is billed exactly as much as a customer.
Clean a list for Amazon SES
Amazon SES has no contact list and no import step, and its 5% review threshold counts from your first send. Verify in your application before mail reaches it.
Clean a list for AWeber
AWeber bills by subscriber across all lists and counts the same address once, so the cost of an unverified import is the bounce rate rather than a duplicated bill.
Clean a list for Braze
Braze users arrive through your SDKs, not a CSV, so validate email inside the app. A hard bounce leaves subscription state alone, so audit the invalid flag.
Clean a list for Brevo
Brevo bills on emails sent rather than contacts stored, so an unverified list costs you send volume and reputation rather than a higher storage tier.
Clean a list for Campaign Monitor
Campaign Monitor bills each client separately and counts an address once for every list it is active on. Merge, dedupe and verify before you import.
Clean a list for Constant Contact
Constant Contact bills on the highest active contact count in a billing cycle, so imports that bounce still cost you. Verify old member lists first.
Clean a list for ConvertKit
ConvertKit, now Kit, bills each subscriber once however many tags they carry. Verify before a migration and after a lead magnet, which draws throwaways.
Clean a list for Customer.io
Customer.io keys people by your own ID with email as an attribute, and workflows fire within minutes. Validate in the signup handler, before identify.
Clean a list for Drip
Drip bills by person and syncs continuously from ecommerce platforms, so verification has to sit at the capture point rather than being a periodic list clean.
Clean a list for Elastic Email
Elastic Email reviews large imports on new accounts, and a suspension there is quick and total. Verify a list before it ever reaches the platform.
Clean a list for Emma
Emma audiences are long-lived alumni, member and donor lists whose work and campus addresses decay fast. Verify once a year and before any appeal.
Clean a list for GetResponse
GetResponse holds large imports for manual review and asks how you collected them, and an address on two lists counts as two contacts. Dedupe and verify.
Clean a list for HubSpot
HubSpot bills by marketing contact, so import records as non-marketing, verify them, and promote only the deliverable ones. The bounced flag persists.
Clean a list for Iterable
Iterable takes users from your product and warehouse through its API, so verification belongs in the pipeline that writes user records, not before a send.
Clean a list for Klaviyo
Klaviyo bills on active profiles and syncs from your store all day, so checkout typos get billed and mailed. Verify before import and recheck on a schedule.
Clean a list for Mailchimp
Mailchimp bills for every contact in your audience, deliverable or not, and judges a new list on its first campaign. Verify the file before you import it.
Clean a list for MailerLite
MailerLite approves new accounts by hand and asks where your list came from. It bills by subscriber, so arrive with a verified list and a consent record.
Clean a list for Mailgun
Mailgun does not check addresses on the sending path, so an address reaches your suppression list only after a real bounce. Verify at capture in your app.
Clean a list for Mandrill
Mandrill has no contact list because addresses come from your own database. Verify at registration, and watch the Mailchimp account that shares its risk.
Clean a list for Marketo
Marketo syncs both ways with your CRM, so whatever you remove can come straight back. Verify at form submission and write the result to a shared field.
Clean a list for Moosend
Moosend bills each unique address once across all your lists, but bounce status is kept per list. Dedupe and verify in one pass before you consolidate.
Clean a list for Omnisend
Omnisend bills subscribed and non-subscribed contacts alike, and only unsubscribed contacts are free. Verify checkout and SMS-only contacts before emailing.
Clean a list for Pardot
Pardot prospects sync to Salesforce leads and contacts, so a deleted prospect is recreated by the sync. Store the verification result in a field instead.
Clean a list for Postmark
Postmark holds no marketing list and keeps suppressions per message stream. For transactional mail, verify at account creation, before you store the address.
Clean a list for Salesforce Marketing Cloud
Marketing Cloud imports into data extensions, so a verification result becomes one more attribute for a send filter. Deleted rows return on the next run.
Clean a list for SendGrid
SendGrid does not check addresses before it sends, and suppressions are kept per subuser. Verify at signup, while the person can still fix a typo.
Clean a list for Sendinblue
Sendinblue and Brevo are one product, so imports behave the same and blocklisted addresses stay blocked account-wide. Verify an old list before relaunch.
Clean a list for SparkPost
SparkPost is API-driven with no real contact list, so verify where addresses enter your system. Read bounce codes before seeding its suppression list.
Clean a list for Zoho Campaigns
Zoho Campaigns syncs with Zoho CRM, so an imported list becomes CRM data and a verification verdict is most useful as a field both systems can read.
Fix ActiveCampaign bounce rate
ActiveCampaign sets a contact to Bounced on one hard bounce or after a soft bounce threshold you can configure, and it reviews accounts that stay above 2%.
Fix Amazon SES bounce rate
Amazon SES puts an account under review at a 5% bounce rate and may pause all sending at 10%. Only permanent bounces count, over its own rolling window.
Fix AWeber bounce rate
AWeber marks a subscriber undeliverable on a hard bounce or after a run of consecutive soft bounces. Most accounts have never checked that threshold.
Fix Braze bounce rate
In Braze a hard bounce marks the address invalid but leaves the subscription state unchanged, and healthy push numbers can hide an email problem for months.
Fix Brevo bounce rate
Brevo blocklists a hard-bounced address across your whole account, not per list, and reviews new accounts by hand. Its guidance is hard bounces under 2%.
Fix Campaign Monitor bounce rate
Campaign Monitor reports bounces per client, so an agency has to check each one separately, yet one client's bad list can draw a review of the whole login.
Fix Constant Contact bounce rate
Constant Contact sorts bounces into six named types, and only Non-existent address removes the contact automatically. That is the count worth acting on first.
Fix ConvertKit bounce rate
ConvertKit records a bounce on the subscriber, which stops every sequence and broadcast at once. Its cold subscriber filter finds the unengaged, not the dead.
Fix Customer.io bounce rate
Customer.io sends from always-on workflows, so bounces arrive as a steady trickle that never spikes. Read the per-person activity log, not only the rate.
Fix Drip bounce rate
Drip sends from behavioral workflows, so a bad address from a store integration can sit in several at once. Fixing the broadcast list does not stop them.
Fix Elastic Email bounce rate
Elastic Email pairs low prices with strict account review, and it suspends senders for bounce rates that a more expensive platform would only warn about.
Fix Emma bounce rate
Emma suppresses a hard bounce at the audience level, so one department's bad send stops mail from every sub-account sharing that audience.
Fix GetResponse bounce rate
GetResponse reviews large imports by hand, so a bounce problem often shows up first as a held import. It treats bounce rates above 2% as a warning sign.
Fix HubSpot bounce rate
A hard bounce in HubSpot sets Marketing email bounced on the CRM contact and blocks marketing email for good. Clearing the flag in bulk brings bounces back.
Fix Iterable bounce rate
Iterable writes a bounce to the user profile and unsubscribes that user from email. Most volume runs through journeys, so no single report shows the bounces.
Fix Klaviyo bounce rate
Klaviyo suppresses hard-bounced profiles with a recorded reason and treats a rate above 2% as a risk. Its deliverability score also blends in engagement.
Fix Mailchimp bounce rate
Mailchimp moves hard-bounced addresses to Cleaned and suspends accounts instead of warning them. Sort the Cleaned list by date to find the import at fault.
Fix MailerLite bounce rate
MailerLite approves every new account by hand, weighing your list source, and can decline it. It expects bounces under 2% and watches new senders closely.
Fix Mailgun bounce rate
Mailgun keeps the full SMTP conversation for each bounce, so you can tell a 550 no such user from a 550 policy block. Pull the logs before retention ends.
Fix Mandrill bounce rate
Mandrill runs under a paid Mailchimp account and shares its compliance oversight, so a suspension on the marketing side can stop your transactional mail too.
Fix Marketo bounce rate
Marketo sets Email Invalid to true on a hard bounce and stores the receiving server's message in Email Invalid Cause. The flag syncs to your CRM for sales.
Fix Moosend bounce rate
Moosend records bounces per mailing list, not per account, so the same dead address can stay live on another list. Check every list, not only one.
Fix Omnisend bounce rate
Omnisend marks only the email channel non-mailable after a hard bounce while SMS and push keep running, so blended metrics look healthy as email fails.
Fix Pardot bounce rate
Pardot, now Account Engagement, marks a prospect undeliverable after a hard bounce or repeated soft bounces, and sales sees it on the Salesforce record.
Fix Postmark bounce rate
Postmark tracks bounces per message stream and publishes distinct types such as HardBounce, Transient and Blocked. Branch on each type in your code.
Fix Salesforce Marketing Cloud bounce rate
Marketing Cloud stores bounces in the _Bounce data view with a category, a subcategory and the SMTP reason. The tracking summary shows none of it.
Fix SendGrid bounce rate
SendGrid keeps Bounces, Blocks, Invalid Emails and Spam Reports as separate suppression lists. Only the Event Webhook delivers bounces in real time.
Fix Sendinblue bounce rate
Sendinblue is the former name of Brevo and runs on the same platform, so a hard bounce blocklists the address account-wide. Current help is under Brevo.
Fix SparkPost bounce rate
SparkPost, now part of Bird, gives every bounce a numeric classification code that separates invalid recipients from policy blocks. Read codes, not totals.
Fix Zoho Campaigns bounce rate
Zoho Campaigns reviews new accounts and large imports by hand and refuses purchased lists, so a poor list usually surfaces as a held campaign.
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