Documentation
Everything about Jepela, the decision API with memory. Every example answer on these pages came from the gateway, and every number says where it was measured.
Start here
What Jepela is, a first decision, and real answers.
IntroductionJepela is a decision API with memory. Send a state and typed questions; get typed answers with probabilities and confidence that your code can branch…Getting started in five minutesJepela is a hosted API at https://api.jepela.com; you need only a key. Everything below was run for real; your numbers will differ a little.Quick startJepela is a hosted API at https://api.jepela.com. There is nothing to install or run. Three steps.ExamplesEvery request on this page was sent to a Jepela gateway on 2026-09-23 and every answer came back from it (jepela-english unless the request names a…Jepela versus JevJev is TypeSafe AI's System One model, served at api.typesafe.ai. Jepela is this API. The request and answer shape is the same on purpose, so code…
Asking questions
The state, the three question types, and what an answer tells you.
StateThe state is what the engine evaluates: a support message, a document, an application record. It goes in the state field next to the questions.PrimitivesThree question types, one request. Each is evaluated on its own against the same state.ChoiceSelect one option from a defined set. The answer has the chosen option, a probability for every option, and a confidence.ScoreRate the state against ordered levels. The answer has a score, a probability per level, the legend, and a confidence.NoulA yes/no statement. The answer is the probability that the answer is yes, with a confidence that is the larger of it and 1 minus it: the probability…ConfidenceEvery answer carries two numbers from 0 to 1: confidence and answer_confidence. They are on the same scale only for a Noul.Request optionsOptions on POST /v1/systemone beyond state, questions, model and subject. Each says what it costs.WarningsEvery answer carries warnings: known traps in this request, found by checks that cost nothing. The answer is returned either way; a warning says…
Memory
Subjects, lines, rules checked in code, and verified forgetting.
MemoryA memory is a list of lines that belongs to one subject of one tenant: facts, events your software reports, rules with conditions, decisions you…Rules in memoryThe memory is read by a one-pass decision engine, not a reasoner. Measured while building the demos and cookbooks with the English checkpoint, four…
Quality and scale
How often it is right on your data, your own model, many decisions at once.
QualityJepela tells you how often it is right on your own decisions, and tunes its confidence to them. Everything here works from labels: the right answer…Fine-tuningTrain a Jepela model of your own on your labelled cases. It is used only if it answers cases it never saw better than the standard engine and still…BatchesMany decisions as one background job: a backlog to classify, a nightly re-scoring, a golden set of your own.PatternsCode owns the control flow. Jepela appears where the code needs a judgment. Four patterns from stateless decision APIs, then two that exist because…CookbooksEnd-to-end recipes in cookbooks/, each a Python script that runs against your gateway with JEPELA_API_KEY set and prints what it measured. The…ModelsGET /v1/models lists what this gateway offers, whether each engine answers right now, and what is pinned.
Reference
Every route, the price and the regions.
API referenceBase URL: https://api.jepela.com (the API of your key's region; see Regions). Every /v1 route except sign-up needs Authorization: Bearer <key>, and…PricingYou pay for input tokens: $0.042 per million input tokens (that is $42 per billion). Output is free. This is the same way TypeSafe prices Jev, at the…RegionsJepela runs in regions. Each region is a whole Jepela: the API, every subject's memory and the engine, in the same part of the world, so a decision…
Clients
Python, TypeScript, and Claude.
Python SDKjepela-sdk 0.2 needs Python 3.10 or newer and nothing else; Pydantic is used only if you give it a Pydantic model. Install it from GitHub:JavaScript and TypeScriptsdk/typescript is a TypeScript client with no dependencies: it uses the fetch built into Node, Deno, Bun and browsers, and Node 22.18+ runs its…Claude and MCPJepela ships as an MCP server and a Claude Code plugin, so Claude can make typed decisions with memory as tool calls.Agent skillFor Claude Code and other coding agents: a skill file, SKILL.md, tells an agent what Jepela is, when to use it inside the software it writes, and the…
Help
Questions, errors, and what the engine gets wrong.
FAQIs Jepela a chat model? No. It never generates text. You send a state and typed questions; you get typed answers with probabilities. Use it inside…TroubleshootingEvery error is JSON: {"error": {"type": "...", "message": "..."}}. The message says what to fix.JaggednessWhat Jepela gets wrong, as measured, so that you design around it rather than find out later. Measured on 2026-09-22 and 2026-09-23 with the Jepela…