Envelopes

I’ve been exchanging budgeting ideas with friends recently, and my budgeting spreadsheet was just too overwhelming. It wasn’t good at chaining scenarios together, and I wasn’t confident in the way it handled inflation.

To share my thinking with friends and family, I made https://envelopes.lukeroh.de. It’s free and MIT-licensed.

I worked with Claude to create it over the past couple of days. I’d been unhappy with Claude’s code bloat on a few recent projects, so for the calculator engine I gave it a lines-of-code budget and made it beg for more. I also insisted it avoid fancy abstractions. For the engine and its CLI, it did a nice job. I let it run out of control on the UI.

Now that code is near-free; UI design is where I need to spend time. I asked Claude for ten different designs, merged the best parts, iterated on a mock UI until I was happy, and then wired up the engine.

It’s got some nice ideas. I wanted to share my budget without a backend and worrying about storing my friends’ data — so I zip the config into the URL. I haven’t seen anyone do that before.

Achieving a goal or milestone simply changes your transfers, which makes stacking milestones easy. You can optionally enable inflation on certain accounts. The slider for inspecting balances at any time is handy. There are alerts for when you run out of cash. It even has an llm.txt so your favourite AI can do your budget for you.

Anyway — balancing a budget over 20 to 40 years is harder than I expected. Finding an early-retirement plan feels like a satisfying puzzle. Still I miss the ad-hoc power of spreadsheets for balancing the books. Perhaps there will be a v2 in the days to come.

I hope some of you find it helpful.