Vibe coding SAFEs
Every founder should be able to see, in dollars, exactly what they walk away with at a $1B exit.
We started this week on a call with founders we’d just term-sheeted. They were confused about their cap table. Not in a basic way. In the way every founder is eventually confused about a cap table.
How much does this SAFE actually cost us? What if we stack another at a higher cap? How much do we lose if we top up the option pool to 15% at the Series A? At a $1B exit, what do we actually walk away with?
They couldn’t answer those quickly. We couldn’t either, sitting on a call, without opening a spreadsheet.
The math compounds in non-obvious ways. Each post-money SAFE locks in investment divided by cap at conversion. Stacked SAFEs at different caps don’t dilute each other. Founders absorb all of it. Pre-money option pool top-ups come out of existing equity, not the new round. Liquidation preferences hurt at low exits and evaporate at high ones.
Founders sign these terms in moments of high emotion. The lead just committed. The lawyer wants to close. You want to get back to building. The second-order effects don’t surface until years later, by which point your ownership is already where it is.
So we built it. A free, single-page tool that lets founders stack SAFEs at any cap, add priced rounds, top up option pools, set exit valuations, and watch the waterfall move in real time. No login, no spreadsheet.
Try it on your own cap table. Drag the exit slider. See exactly how much you walk away with.
We vibe coded it in <30 minutes. The source is on GitHub. If anyone wants to add features or fix corner cases, send a PR.