Field Notes
Notes May 12, 2026 · 3 min

Building Extra Dollar in public

Our first venture is in build. Here's the demand signal that convinced us, and what we're testing next.

Extra Dollar started from a plain observation: almost everyone carries multiple cards, and almost nobody uses the right one. The rewards are real, the rules are a moving target, and optimizing by hand is a chore nobody signs up for.

Why we believed it

We didn't write a thesis deck. We looked for people already trying to solve this for themselves — spreadsheets, forum threads, half-built apps — and found plenty. That's the demand signal we build on: not what people say they'd use, but what they're already hacking together.

If people are already building a worse version of your product by hand, you've found something.

What's next

We're widening the early-user group and pressure-testing the recommendation engine against real spend. The bar to move from Build to Prove is simple: does it put more money in people's pockets than the effort it asks of them? We'll know soon.

Phase One Ventures · Field Notes
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