With shopify buying TailwindCSS, I thought, "hey, I definetly had this on my tech bingo card."
So then I thought it'd be fun to build an app to generate these.
Put in your X handle (optional), get a card with a permanent URL, download it as a PNG. No signup, no cookies beyond the admin one nobody but me uses.
How it's built, since that's the part HN actually cares about: one Cloudflare Worker with Hono, D1 for storage, Tailwind v4, and workers-og (Satori + resvg) for the PNGs. The PNG rendering was the only hard part. Satori only speaks a subset of flexbox, so the HTML card and the image card are two separate renderers reading from one theme file so they can't drift. Cold renders take a few seconds, longer than social crawlers wait, so PNGs are pre-rendered at card creation, stored as blobs in D1, and cached at the edge.
The 120ish squares are hand-written. There's an admin page where Claude drafts new ones and I approve or reject them one at a time. Roughly a third of its drafts survive.
Happy to hear which squares you'd add. "Cloudflare outage breaks the web" is already on there, in case you're wondering whether this site is exempt.
Added special event bingo cards:
https://techeventbingo.com/railsworld-2026 https://techeventbingo.com/apple-9-26
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