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.
✓ 7-day free trial·✓ Cancel anytime
2×
revenuerevenue in Primary
How much the Gmail Promo Tab costs you at every send.
Up to 70% of marketing emails end up in the Promotions tab, where open rates drop by almost half 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.
How much you lose
−€900
1,800 people never read it because of the Gmail Promotions tab.
Why you lose money
Lands in Promotions
21%
open rate
Lands in Primary
39%
open rate
Assumes 1% of readers buy.
We beat the Promotions tab.
Stringer tests your email on real Gmail and rewrites it until it lands in Primary.
We brute-force your email on your own Gmail accounts, one or more. Real inboxes you control, so every test is yours to check.
Stringer sends your email piece by piece and detects exactly which chunks push it into Promotions or Updates. Not a score, not a guess: the tab Gmail actually picked.
Real tests
On your Gmail accounts
AI rewrites
Until it lands in Primary
Testing line 1 of 8 in real Gmail…
1 sendsEmail Map
Hey Alex, we have been busy this month and I wanted you to hear it first. Limited-time offer: 50% off every plan for the next 24 hours! The dashboard you asked for is now live. Your monthly usage report is ready. Shop now before it expires! Just reply to this email if you have any questions. Marco
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 diffPricing
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.
Monthly
Pay month to month.
- 2,000 test sends a month
- 500 AI rewrites a month (one rewrite = one rewritten line)
- Unlimited rewrites with your own Anthropic keyYour own API key from console.anthropic.com. Add it in Settings and the AI rewrites run on your Anthropic account, billed by Anthropic at their prices. A typical email fix takes about 10 rewrites, around $0.05.
- 2 sending domains
- 7-day free trial
Annual
Pay once a year, 2 months free.
- 2,000 test sends a month
- 500 AI rewrites a month (one rewrite = one rewritten line)
- Unlimited rewrites with your own Anthropic keyYour own API key from console.anthropic.com. Add it in Settings and the AI rewrites run on your Anthropic account, billed by Anthropic at their prices. A typical email fix takes about 10 rewrites, around $0.05.
- 2 sending domains
- 7-day free trial
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 close to half of 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.
How much do rewrites cost on my own Anthropic key?
Very little. One rewrite is one rewritten line, and a typical email fix takes about 10 rewrites, around $0.05 on your key. Anthropic bills you directly at their prices. On Monthly and Annual your 500 included rewrites a month are used first; on Lifetime every rewrite runs on your key.
Your next campaign doesn't have to be buried.
Land in Primary. Try it free for 7 days, cancel anytime.
Get started