what teresa costs
teresa is free and has no plan to stop being free. this page shows what that costs, in real money, so the deal is visible: what comes in, what goes out on servers and the phone line, and what every message costs in Claude API calls. the api numbers are not estimates - they are priced from the token counts the api returns for every single call.
revenue
$0.00 per month. no plans, no ads, no data sold - see the privacy policy. if that ever changes it changes here first.
fixed costs
the same every month, whether anyone texts or not.
| item | per month |
|---|---|
| server | $5.00 |
| domain | $0.31 |
| total | $5.31 |
api spend, august 2026
every message anyone sends is read once by a small model that decides whether it is an expense (that is the 💸). replies - summaries, corrections, questions - run a bigger model. both are priced at anthropic's list rates from the exact tokens each call used, cache reads and writes included.
| model | used for | calls | tokens | cost |
|---|---|---|---|---|
claude-opus-5 | replies | 13 | 176,196 | $0.45 |
claude-sonnet-5 | replies | 1 | 9,030 | $0.04 |
| total | $0.49 | |||
37 messages read and 8 expenses logged this month across 4 chats - about $1.45 per active chat, everything included. $0.49 spent on the api since 2026-08-28.
the rates
usd per million tokens, list prices as of 2026-06.
| model | input | output | cache read | cache write |
|---|---|---|---|---|
claude-sonnet-5 | $2 | $10 | $0.2 | $4 |
claude-haiku-4-5 | $1 | $5 | $0.1 | $2 |
what is not here
- time. nobody is paid to build or run teresa. the hours are not on this page because they are not a bill.
- the demo pages. the three example ledgers on the home page are seeded, not used; their rows are excluded.
- rounding. everything is integer cents; a call that costs a fraction of a cent rounds to zero on its own line but is counted in the totals.
questions
ask by teresa@lasagna.pizza.