RESOURCES
Changelog
Notable changes to the developer platform and its documentation, newest first.
29 October 2026
- Documentation rebuilt: new navigation, search, model pages for Z1, Z1 Code, H1 and Project ZERO Alpha, a complete API reference, and examples that are run against the production API contract.
- Console Playground: send real streamed requests, with tokens and exact cost shown for each answer.
- Project ZERO Alpha: private enrollment with a daily allowance of 200 requests and 30 requests a minute per developer.
- Z1, Z1 Code and H1: private pilot begins for enrolled accounts, billed from a prepaid wallet at the published prices.
- Console: refreshed interface; key management, wallet and usage views connected to the Gateway.
Corrections to earlier documentation
- Earlier pages said Console keys do not work against api.tessen.ai. They do: Console keys are
tes_keys that authenticate https://api.tessen.ai/v1. - An earlier page said reasoning content is never returned. For reasoning models, non-streaming responses can include
reasoningandreasoning_content; they are not part of the stable contract. - Earlier pages said Tessen reports no cost and publishes no prices. Prices are published, and the cost of a request on Tessen's families is reported.
- An earlier page described a 400
reasoning_budget_exhaustedfor Tessen's families. When output runs out during reasoning, the families answer 200 with empty content andfinish_reason: "length".
Note
Entries are added only for changes that are live. Planned work is not listed here.