What it costs to run EloCoach, and why the free tier needs a gate

People ask whether EloCoach will stay free. The honest answer needs numbers, so here they are. EloCoach is paid for today out of my own pocket, and this is what that pocket is covering.

The monthly bill, beta edition

Call it roughly $60 a month. That is a fine number for a side project. It is a misleading number for a product, because almost all of it is either fixed or running on goodwill.

What changes when people show up

The cheap part of the design is that Stockfish and Maia run on your phone. Reviewing a game costs us nothing no matter how many games you review, and I do not want to charge for that. Everything below is what does not stay cheap.

• The language model bill is linear. Each coach diagnosis is a long prompt with your games and your memory in it, and a long answer. Ten times the diagnoses is ten times the bill. There is no clever discount on that curve until we have volume.
• The backend and database grow in steps. A bigger instance, a bigger database, maybe a second region. Not smooth, and not optional once people depend on it.
• Free tiers end. Analytics, background jobs, email and the GIF service all have free allowances that are generous at beta size. The GIF service’s testing key, for one, allows about a hundred calls an hour. Each upgrade is small on its own and a real line item together.
• Running a business costs money that is not technology. A business bank account, tax and accounting software, someone to check I am doing the paperwork right. None of it shows up in a hosting invoice and all of it arrives the day someone pays you.

Why a free tier needs a gate

An open tap on a linear cost is not generosity. It is a countdown.

If everyone can run unlimited coach diagnoses for free, then the better the product gets, the faster it costs me money, and the first viral week ends the project. So the beta already has the gate built in, in two places.

• The product splits cleanly. Reviewing your games, the board, the eval timeline, the engine and Maia analysis, is unlimited. What is metered is the coach diagnosis, the expensive language model part. Free currently includes five a month.
• Every user has their own model key. The key is created when you sign up, and it can carry its own spend limit at the provider. If one account goes wild, it hits a wall on its own, and nobody else’s coaching suffers.

We have planned tiers on the pricing page, Free, a Premium at €5.99 a month and a Pro at €14.99, all marked coming soon. Treat those as placeholders until real usage tells us what a diagnosis costs.

How I want to price it

As fairly as I can make it work. That is not a slogan, it is a to-do list:

• Keep what costs us nothing, engine review, free.
• Charge for the part that has a real marginal cost, and nothing more.
• Keep trimming that cost. Shorter prompts, smarter caching, and cheaper models where they do the job equally well. Every cent we save is a reason not to raise the price on the people who joined early.
• Say what the money is for, in public, like this.