Justin Krup

Engineer. I built the trends system at Snap Inc. and co-founded . Now I push the boundaries of what's possible with AI. Everything below is live. Touch it.

Capdle · daily game

Guess the object with your camera.

Drag to look around. Press the shutter.

One secret everyday object a day, and six photos to find it. Every photo comes back as five tags: what it's for, where it lives, how big it is, what it's made of, its shape.

Green is right, yellow is close, and the size arrow points toward the answer. This is a pocket version with a printed room. The real one uses whatever's on your desk.

Peekablur · iPhone

Share the video, not everyone in it.

Tap a face to hide or show it.

Peekablur finds every face in a video and covers it on the phone itself. Nothing is uploaded, and it works in airplane mode. You tap the faces you want to keep.

I made it for someone who wanted to post her kid's birthday without posting everyone else's kids. The pixelate and blur here are the real thing, run on the printed faces every frame.

Halo AI · co-founder

You decide. Agents execute.

Agents for creator marketing
Tap a pink ring to approve a creator

Halo runs creator marketing with agents. One finds the creators who fit a brand, one pitches them, and one keeps every collab on schedule. A person signs off at each step.

We raised a $6M seed, and brands on Halo get 2.7× the collaborations on the same budget.

Livoice · voice API

Same conversation, different voice.

Hold to talk over it. Pick a voice.

GPT-Live-1 listens while it talks. It waits while you think, says "mhmm", and cuts in with a correction. It only ships with OpenAI's voices.

Livoice sits in the stream and swaps the voice. Everything else arrives unchanged, about 200 ms later. It's one URL and one header. Clone a voice from a minute of consented speech, or use one of the two ready ones: a Japanese tutor, and mine.

jeveryword · open source

A model that can't write a word, extracting text.

Tap to ask the next question

Jev, from TypeSafe, only answers multiple choice. It picks and never writes. So jeveryword numbers every word of your text and offers the numbers as the choices. Jev picks a start and an end, and the answer is sliced straight out of the original.

Every value it returns is exactly what the text says, character for character. It's open source, with a hosted x402 API.

The silly one: askjevs.site, where every question you ask gets answered by picking.

Also

  • meteor-nowDeploy a Meteor app in one command. 335 stars on GitHub
  • Puppy PunchMade video games, once. A Game With BALLS, 2011.