Operator OS vs. Wave
Wave's core accounting is free, and it stays free -- Wave makes its money on card processing, not a subscription. That's a genuinely good deal for a business whose main need is sending invoices. It's a different deal once you ask the question Wave's dashboard can't answer: which week, specifically, do I run out of cash.
Wave is free at its core: the Starter plan costs nothing and includes unlimited invoices, unlimited bills, and double-entry bookkeeping records. Wave makes its money on payment processing -- 2.9% + $0.60 per card transaction (3.4% + $0.60 for Amex) -- and on two paid add-ons: Pro, at $19/month, which adds automatic bank imports and transaction categorization, and Wave Advisors, a human-bookkeeper service starting around $149-199/month for businesses that want someone else to do the books entirely.
What Wave gets right
For a business whose real need is "send professional invoices and keep basic books without paying a subscription," Wave is a legitimately good deal, and the free-plus-payment-fees model means a slow month costs nothing beyond the card fees you'd pay anywhere. It's cloud-hosted and simple to start with no CLI, no file to manage, nothing to install. Operator OS doesn't compete on that axis -- it asks for a one-time payment up front and a comfort with a command line that Wave's dashboard was built to avoid entirely.
Where Operator OS differs
Wave's own pricing page describes what the product does: manage cash flow and customers from a dashboard, with profit-and-loss and other standard reports. Nowhere in Wave's published materials is there a forecast that models uncertainty -- no simulation, no probability range, no answer to "given how late my customers actually pay, what are the odds I run dry before the 20th." It reports what already happened and what's currently owed; it doesn't model what's about to happen.
That's the specific gap os sim fills: 2,000 runs of the same 90-day forecast, each one drawing from how long your own customers have actually taken to pay in the past, reporting a distribution -- bad case, middle, good case -- instead of a single balance. os whatfirst then ranks which one collection or expense change would move those odds the most. Wave has no equivalent feature at any price, free or paid.
The other difference is where the money goes and where the data lives. Wave's free tier is subsidized by payment processing fees on every transaction you run through it, so the real cost scales with your revenue, not your subscription tier. Operator OS is a flat one-time price with no transaction fee at all -- it doesn't process payments, so there's nothing to take a cut of. And because the books are plain CSV and YAML files on your own disk rather than rows in Wave's hosted database, there's no dashboard to log into and nothing to export if you ever want to stop using it -- the files already are the business.