ByeByePromoStop landing in
Promotions.
ByeByePromo pinpoints the exact lines Gmail is flagging as promotional — then rewrites them with Claude until your email lands in Primary, where people actually read.
✓ 48h money-back guarantee·✓ Cancel anytime
+250%
open rates
The problem
You wrote a great email.
Gmail buried it.
Up to 70% of marketing emails end up in the Promotions tab — a graveyard where open rates drop 3–5× and your message sits next to coupons nobody asked for.
Every word, every link, every image in your email is scored. One unlucky phrase and the whole campaign lands in the wrong tab. You never know which word did it — until now.
A typical scan result
Wrong solutions
Tired of advice that doesn't work?
Here's what you've probably already tried — and why it didn't move the needle.
“Just ask your subscribers to drag it to Primary.”
Haha. Works great if you have 10 subscribers and they love you. At any real scale, you're begging people to do admin for you — and most of them won't even open the email to drag it in the first place.
“Avoid these 200 spam trigger words.”
Gmail's filter is a machine-learning model, not a keyword list from 2007. Strip every "free" and "limited" out — it'll still land in Promotions because filters look at tone, structure, links, and image ratio, not word bingo.
“Just get 10/10 on Mail-Tester.”
Mail-Tester checks your SPF, DKIM, DMARC, and headers. Important stuff, but a perfect score tells you nothing about whether Gmail reads your copy as marketing. You can pass it and still land in Promotions.
“Warm up your IP for 6 weeks.”
Warming matters for brand-new senders — fair. But it doesn't fix a campaign that lands in Promotions because of what it says. Perfect reputation, wrong tab, same result.
None of the above tells you which of your sentences Gmail flagged. We do — empirically.
We don't guess. We test.
Stringer is our proprietary scan-and-rewrite engine — a disciplined loop that chunks your email, experiments on real Gmail, and measures actual outcomes until your message lands in Primary.
Green and red aren't scores or opinions. They're measured outcomes — specific to your email, read straight from the Gmail API.
Every rewrite is sent again. Every winner is cross-checked on a second inbox before we call it one. Same rigor a clinical trial uses, applied to your subject line.
~4
Avg iterations
1 – 3
Inboxes tested
Gmail API
Data source
2×
Cross-checked
Stringer engine
scanning · real Gmail
Hypothesize
Chunked email, flagged suspects
Experiment
Sent each variant to real Gmail
Measure
Read tab directly from Gmail API
Verify
Reproduced winner on second inbox
Winner found in 4 iterations
Confirmed Primary on matteo+2@gmail.com
How it works
Three steps. One email that actually arrives.
Paste. Scan. Ship. Real Gmail every step of the way.
Paste your email. That's the whole setup.
Subject, body, HTML wrapper — drop it in and pick the sender you want to test from. No formatting dance, no spec file to write.
- Any length, any tone — marketing or transactional
- Bring your ESP template (Mailchimp, Klaviyo, Brevo, …)
- Send from a verified domain you own
Compose
Email Map
Activity
3 sends[T-9f2a] Your book preview is ready
Primary[T-4d1c] Your book preview is ready
Promo[T-c2e9] Your book preview is ready
PrimaryWe send through real Gmail. Not a simulator.
Stringer chunks your email and sends each piece through actual Gmail inboxes you've connected. You watch lines turn green or red in real time — no guessing, no score from a black box.
- Real inbox testing — no heuristics, no simulation
- Every line marked green or red, live
- Cross-check across multiple Gmail accounts
Claude rewrites. We keep testing. You win.
Every flagged line is rewritten in context — Claude sees your full email so replacements don't duplicate what's already there. The loop keeps running until your winner lands in Primary, then we double-check on a second inbox to be sure.
- Rewrites match your tone, not marketing boilerplate
- URLs, names, dates preserved exactly
- Winner cross-checked on a second inbox before we call it
Winner found after 4 rewrites!
Double-checked on a second inbox · confirmed Primary
Winning email
4 attempts · word diffWhat you get
Built for people who actually ship emails.
Not another score. Real Gmail, real fixes.
Real Gmail testing
We send through real Gmail accounts. If we say it lands in Primary, it lands in Primary — no simulation, no guesswork.
Line-by-line precision
Stringer highlights exactly which line triggers the filter. Surgical fixes, not a full rewrite of a campaign you already liked.
AI rewriting, with context
Claude sees the whole email — not just the red chunk — so rewrites fit cleanly alongside your good lines without redundancy.
Cross-check on a second inbox
Once we find a winner, we double-check it on a different Gmail account to make sure it holds up, not just a fluke.
Your ESP template
Wrap your email in the real HTML your ESP sends so results match production — not a stripped-down preview.
Your own domain
Send from a verified domain you control. Your sender reputation is yours to build, not borrowed from a shared pool.
Pricing
Two plans. Pick your volume.
Both plans include everything you need to land in Primary — Stringer scans, Claude rewrites, ESP templates, your own sender domain.
Starter
For solo senders and newsletter writers.
- 20 scans per month
- 1 Gmail test inbox
- 1 verified sender domain
- Email body up to 2,000 characters
- Claude-powered rewrite loop
- ESP template support
- Email support
Pro
For agencies, growth marketers, and heavy senders.
- 100 scans per month
- 3 Gmail test inboxes· unlocks cross-check
- 3 verified sender domains
- No email body size cap
- Claude-powered rewrite loop
- ESP template support
- Priority email support
Questions
Things people ask first.
What's the Promotions tab, again?
It's the default Gmail tab where marketing-flavored emails land automatically. Open rates there are typically 3–5× lower than Primary — because people rarely look. If your campaigns end up there, most of your audience never sees them.
How is this different from Mail-Tester or GlockApps?
Those tools score your email against spam heuristics (SPF, DKIM, links, auth). Useful, but they can't tell you which of your sentences Gmail thinks reads as promotional. ByeByePromo sends to real Gmail and maps Promotions triggers line by line, then fixes them.
Do I need a verified sender domain?
Yes — we send from your domain so you're testing the exact conditions your real campaigns face. We guide you through the DNS setup (SPF, DKIM, DMARC) in under 5 minutes.
Will this work with my ESP (Mailchimp, Klaviyo, HubSpot…)?
Yes. You paste your ESP's HTML template once; we wrap every test email in it so what we test matches what ships. If your winner still lands in Promo through your ESP, we have a troubleshooting playbook for that too.
Your next campaign doesn't have to be buried.
Land in Primary — or get a full refund within 48 hours. No questions asked.
Get started