Show HN: Make senders work to get into your inbox https://ift.tt/9D6aOZF

Show HN: 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 have been abused like this. Captchainbox applies the idea of proof-of-work to email. If a sender is willing to do a bit of work to reach you, the message is more likely to be worth your time and the sender more likely to be real. The work is a traditional captcha. You can also set a pay-to-deliver amount if you want more friction. The proceeds of the delivery payment after transaction costs go to the Internet Archive and the EFF. The tool currently works by authing with your Gmail or Outlook and during launch time I make this completely free as a lifetime deal (with optional payment if you wanna support). How it works: Captchainbox builds a whitelist automatically from the metadata of your past correspondence. If you've emailed an individual address, that sender can reach you. If you talk to several people at the same domain, we whitelist the whole domain. If one transactional-looking sender has sent you more than 10 emails, we treat it as a transactional domain and let it through. This whitelist is for you to change whenever you want. It continues to build organically as you converse with more addresses. Incoming mail is checked against that whitelist. Senders already on it land in your inbox as normal. Anyone else gets archived (never deleted) and is sent a challenge. This can be the captcha or the payment link. Once they solve it, their email is pulled out of the archive and put back into your inbox. if you want to see what this looks like from a sender's point of view, send me an email here: doerpfelix15@gmail.com The service only ever reads metadata, never message content. And since nothing is ever deleted, you can't lose a message. There is a legitimate risk / downside: if you sign up to a new service, these emails also land in the archive. Since we do not process the content, a first-time sender who can't solve the challenge (say an automated activation email) will sit in your archive until you spot it. Happy to answer anything! :) https://ift.tt/ViezY4q July 15, 2026 at 05:28PM

Show HN: Beautiful Type Erasure with C++26 Reflection https://ift.tt/ZuP2oi8

Show HN: Beautiful Type Erasure with C++26 Reflection Try it on Compiler Explorer: https://ift.tt/d6SNXpj Check out the source code: https://ift.tt/fD7xqn0 https://ryanjk5.github.io/posts/rjk-duck/ July 14, 2026 at 06:10PM

Show HN: A device for never missing the surf turned into something more https://ift.tt/31LSldp

Show HN: A device for never missing the surf turned into something more https://ift.tt/9ySnNdx July 15, 2026 at 12:42AM

show hn: 1d data to 3D topology, AI deepfakes to protien folding https://ift.tt/YlBTJpS

show hn: 1d data to 3D topology, AI deepfakes to protien folding https://ift.tt/AEMbP3h July 14, 2026 at 10:59PM

Show HN: Super Dario https://ift.tt/oTUMIyf

Show HN: Super Dario https://ift.tt/wk6vfMJ July 13, 2026 at 11:23PM

Show HN: Connect a voice agent to your phone as a Bluetooth headset with a ESP32 https://ift.tt/5e8aFpO

Show HN: Connect a voice agent to your phone as a Bluetooth headset with a ESP32 Just a bunch of sub-$20 ESP32-A1S components and you can snap a voice agent into your smartphone and take all the calls for you https://ift.tt/w86XgbT July 13, 2026 at 10:56PM

Show HN: Scramble Quest https://ift.tt/TAmqQNu

Show HN: Scramble Quest https://ift.tt/YLhUE92 July 12, 2026 at 11:28PM