Make senders work to get into your inbox
Hi HN :) really excited to share this with you. The one thing AI reliably does is generate noise. Half the tools I see launch are just machines for producing more noise across more channels. And people are starting to see this in the form of emails in their inboxes as spam filters are struggling. There used to be a useful signal in email: the effort a sender put into customizing a message was a rough proxy for how relevant it actually was. AI killed that. Now it's customized slop with the appearance of effort with none of the cost. It is painful that the open internet / open channels…
Make senders work to get into your inbox launched on July 15, 2026 with 44 votes, #638 of 24,623 launches that month and more than 95% of that year's launches.
In plain words
Captchainbox is an email filtering tool that requires senders to complete a CAPTCHA or pay a small fee to deliver messages to your inbox. It works by adding a proof-of-work barrier designed to reduce spam and AI-generated bulk emails, making senders demonstrate genuine effort or intent before reaching you. The tool is for anyone receiving excessive unwanted email and wanting to restore signal from noise in their inbox.
written from the facts on this page · September 2026
From the sources
Make senders work / pay 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. test what this looks like for the sender by sending me a msg: [email protected] free for individuals, msg me for teams :)
Set a price for unknown senders to reach your Gmail inbox. Trusted contacts get through normally, and you choose where 90% of the post-Stripe amount goes.
Their message stays out of your inbox until they pay the price you choose. Trusted contacts get through as usual. Completely free to use. Free to use. Estimate includes Stripe processing and Captchainbox's share. Actual results vary. Spam filters catch obvious junk. Personalized cold outreach still consumes your time. Captchainbox makes senders put money behind the interruption. Captchainbox checks your conversation metadata. We never read your messages. We build a trusted contacts and accounts list for you. For every new message Captchainbox checks the sender against your trusted contacts. Unknown senders are held safely and receive a pay to deliver link. Introductions through trusted…from captchainbox.com
In the maker’s words, at launch
Hi HN :) really excited to share this with you. The one thing AI reliably does is generate noise. Half the tools I see launch are just machines for producing more noise across more channels. And people are starting to see this in the form of emails in their inboxes as spam filters are struggling. There used to be a…
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Hi HN! I'm Louw, founder of the enterprise insurtech scale-up Root[0]. Over the last 8 years, my inbox has been flooded with unsolicited emails, especially since early 2023. Recruitment services, outsourced software development agencies, and a crazy amount of lead generation services (thanks, Apollo!) drowned my inbox. To solve this, I created Unspam. Initially, it was a simple tool for myself and fellow founders to reduce noise. And it worked — about 10% of my emails were swiftly and accurately categorized as unsolicited messages. Given its success, I've decided to package and share Unspam…
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Source: Show HN post ↗ · launch text quoted in part
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