The Email Deliverability Checklist for 2025

If your bounce rate creeps over 2%, ESPs start treating you like a spammer.

That’s not speculation — it’s the unwritten rule of email marketing.
Once your sender reputation drops, you don’t just lose one campaign. You lose inbox placement for every campaign that follows.

And no, you can’t just “email your way back in.” This is one of those cases where prevention really is the only cure.

Before You Send — Build for Deliverability

Clean, verified data is your first line of defense. Before a single email leaves your server:

• Verify every address — not once a year, not once a quarter, but before every major send. Tools that give you “catch-all” or “unknown” are useless here; you need yes or no.
• Remove inactive and bounced addresses — if an address hasn’t engaged in months or bounced once already, it’s dead weight. Sending to it only hurts you.
• Segment your list — smaller, more relevant sends drive better engagement and fewer spam complaints. Don’t blast everyone with everything.

Operators don’t “trust the list.” They clean it. Every. Single. Time.

After You Send — Protect Your Reputation

What you do after the campaign is just as important as the prep. Post-send hygiene is how you keep your good standing with ESPs:

• Track bounce rates live — if you see a spike, hit pause immediately. Find the source of the bad data before you keep sending.
• Remove problem addresses — delete hard bounces, inactive subscribers, and addresses that repeatedly fail to click or open. They’re hurting your engagement metrics and triggering filters.
• Avoid catch-alls entirely — even if they sneak past other tools, they’re a delayed bounce waiting to happen. TLDR Verify flags and strips them before they can bite you.

Deliverability is never “set and forget.” It’s discipline before and after every campaign.

Win the Inbox Before You Hit Send

Every email you send is either building your reputation or tearing it down.

If you want better inbox placement, cleaner metrics, and more revenue, you can’t afford to send to “maybe” addresses.

Run your list through TLDR Verify to get a clear yes or no every time, and keep your bounce rate under the danger line.