Stop AI cold spam

Make unknown senders work to get into your inbox.

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.

OtherSoon

See how it works

7-day free trial · 5-minute setup · Archived, never deleted

Mail

Search mail

Live

Inbox3

Archived2

Trusted284

InboxArchived 2Trusted 284

SC

Sarah Chen

now

sarah@designco.com

Re: new design direction

Checking sender…Delivered to your inbox

Verified sender

2 awaiting verification

Proceedings are donated to

Pooled and donated annually, 50/50. See the ledger.

Built for inboxes overwhelmed by AI outreach

AI cold outreach is nearly free.
Make senders work for your time and attention.

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

Sign in with your email provider.

Captchainbox scans your conversation metadata. We never read your messages. We build a trusted sender and domains list for you.

Sign in with your email provider

Gmail connected

you@gmail.com

Scanning sent history…0%

Analyzed

2,847

Trusted

284

Status

Active

Step 02

Every sender checked silently.

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.

See how filtering works

Inbox protection

Live

Step 03

Senders show they are worth your time and attention.

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.

See the verification flow in action

captchainbox.com/verify/···

Inbox verification

This inbox uses a quick CAPTCHA. Complete it to get your message delivered.

Recipient picked: CAPTCHA

Complete the CAPTCHA

I am human

Deliver my message

You're verified

Your message is on its way to their inbox.

Pricing

Simple pricing to get back your time and attention.

Free 7-day trial, no credit card required.

Per inbox

$5/ month

7-day free trial included

Real-time inbox filtering
Calendar invite protection
Trusted circle from sent history
Introduction detection via CC
Configurable filter rules
Custom auto-reply templates
Emails archived, never deleted

Start free trial

Take back your inbox.

Set up in 5 minutes. Free to get started.