Stop AI spam from flooding your inbox and calendar. Unknown senders solve a CAPTCHA or pay a fee to get in. Trusted contacts get through as usual.
7-day free trial · 5-minute setup · Archived, never deleted
Prove you are human
Sarah Chen
[email protected]
Re: new design direction
Sarah Chen
Re: new design direction
Stripe
Receipt for your subscription
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PR #842 was merged
Proceedings are donated to
Pooled and donated annually, 50/50. See the ledger.
Built for inboxes overwhelmed by AI outreach
Spam filters catch the obvious, but mass-customized outreach gets through. You miss what matters and drown in what you didn’t ask for.
Step 01
Captchainbox scans your conversation metadata. We never read your messages. We build a trusted sender and domains list for you.
Gmail connected
[email protected]
Analyzed
2,847
Trusted
284
Status
Active
Step 02
For every new email Captchainbox checks the sender against your trusted contacts. Unknown senders are archived (never deleted) and sent a verification link. Introductions through trusted contacts get through.
Step 03
Unknown senders verify through a CAPTCHA or pay a small fee to show they are relevant to you. They complete the verification and their email is delivered to your inbox. Payment fees get pooled and donated.
Inbox verification
This inbox uses a quick CAPTCHA. Complete it to get your message delivered.
Complete the CAPTCHA
You’re verified
Your message is on its way to their inbox.
Pricing
Free 7-day trial, no credit card required.
Pay once, keep forever
7-day free trial included
Set up in 5 minutes. Free to get started.
Curious what senders see? Send me an email and see the verification flow yourself.
From the blog
We never read your emails. Captchainbox filters by sender identity only, never message content. Your conversations stay private.
Independently security-audited. Captchainbox passed a CASA Tier 2 security assessment, Google’s required audit for apps accessing Gmail data.
