How is this different from calling the REST API directly?

You get a builder plus typed accessors: `NoulQuestion` with `isTrue()` true above 0.5, `ChoiceQuestion` with per-choice probabilities, `ScoreQuestion` with legend and probabilities, plus usage on every response.

What state shapes can I send with a request?

Text state goes through `withSimpleState`, or pass a JSON-serialisable object to the `SystemOneRequest` constructor. Answers are retrieved by the identifier given to `withQuestion`.

How do timeouts and failures behave?

`withTimeout` sets the connection timeout defaulting to 30 seconds, and each HTTP request carries a fixed 30-second timeout. Network or unreadable responses throw `TypeSafeAPIException`.

What are the setup catches on a fresh machine?

JDK 25 with `JAVA_HOME` is required, the JAR lands in `typesafe4j-core/build/libs/` with declared runtime deps on the classpath, and tokens omit the `Bearer` prefix the client adds itself.

How do I supply the TypeSafe token to the client?

Pass a credential provider when building: EnvironmentTypeSafeCredentialProvider reads TYPESAFE_AUTH_TOKEN, BasicTypeSafeCredentialProvider takes a token in its constructor, or implement TypeSafeCredentialProvider to load from another source. Tokens omit the Bearer prefix; the client adds it.

Which models can I select per request?

The request builder defaults to Model.JEV_LATEST, and you can choose Model.JEV_PREVIEW or pass an API model alias to withModel(String). Model selection is per request, so different calls can target different Jev releases.

Does the client publish to Maven Central?

No. Artifact publishing is not currently configured in the repository, so build the typesafe4j-core JAR from source with ./gradlew :typesafe4j-core:assemble and put it plus its declared runtime dependencies on your classpath. On Windows use gradlew.bat.

CommunityJev Repos & SDKs

Typesafe4j

Java client for the TypeSafe System One API: send yes/no, choice, and scoring questions in one request and read typed answers with confidence scores and token usage.

See highlights

Open github.com

Stars: 1
Language: Java
Published by: Community
Author: oskarscot
Last verified: Oct 2026

oskarscot/typesafe4j

User repository on GitHub

View on GitHub

Modern and lightweight Java SDK for the TypeSafe AI Jev models

Forks: 0
Last pushed: Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.

About this project

A Java client for the TypeSafe System One API. Send yes/no, choice, and scoring questions in one request and read typed answers with confidence scores and token usage. JDK 25, with JAVAHOME pointing to your JDK. A TypeSafe API token for live requests. The client lives in the typesafe4j-core module. Build its JAR from the repository root:

Quoted from the project's README. Read the full README.

Tagscommunity github

Works forJev for Classification

Used inJev for Software & DevTools

Languages: Java

Highlights

Builds the `typesafe4j-core` JAR with `./gradlew :typesafe4j-core:assemble` (`gradlew.bat` on Windows).
Reads the token from `TYPESAFE_AUTH_TOKEN` or a constructor-supplied provider; the client adds the Bearer prefix.
Defaults to `Model.JEV_LATEST`, with `JEV_PREVIEW` or a string alias selectable per request.
Typed lookups throw `IllegalArgumentException` for missing answers and `IllegalStateException` for type mismatches.

Watch out

Requires JDK 25 with `JAVA_HOME` set; artifact publishing is not configured, so build the JAR from source. Copy reviewed against the repository README on 2026-10-04, not from running it.

Questions about this entry

Short answers drawn from the linked project or page.

More Jev resources like this

jev4j

Java SDK for TypeSafe with typed noul, choice, and score handles: pass records, maps, or strings as state and read answers back by handle or explicit key.

Jev Repos & SDKs#community#github

Community

galitianu/jev4jJava

jev

Go Unix CLI that pipes state on stdin into one Jev question — noul, choice, or score — across TypeSafe, Cloudflare, and Vercel providers, printing machine-readable JSON and signaling success by exit code.

Jev Repos & SDKs#community#github

Community

stefafafan/jevGo

typesafe-client

Unofficial Go and Rust clients for the System One API covering noul, choice and score questions, with env-based config, retries, typed errors and gateway support.

Jev Repos & SDKs#community#github

Community

haileyok/typesafe-clientRust

typesafe-ai-java

JVM SDK for the TypeSafe System One API with a pure-Java core, Kotlin DSL, Spring Boot starter, and Spring AI bridge, speaking the System One wire contract across hosted and self-hosted backends.

Jev Repos & SDKs#community#awesomejev#catalog-import

Community

jamilxt/typesafe-ai-javaJava

taurus-jev-sdk-go

Zero-dependency Go client for the TypeSafe System One API with typed noul, choice, and score questions, strict response validation, and safe concurrent use.

Jev Repos & SDKs#community#github

Community

KKloudTarus/taurus-jev-sdk-goGo

jev-rs

Community Rust client for the TypeSafe API with async and optional blocking clients, typed Noul, Choice, and Score questions, retries, and structured errors.

Jev Repos & SDKs#community#github

Community

abeldzan/jev-rsRust

From the Jev guides

Original write-ups on what this entry is for.

The Open Reimplementations: Local Models That Speak System One

Sep 22, 2026

Closed weights have not stopped the ecosystem from rebuilding the shape in the open. API-compatible servers, retrained heads on small models, and inference-time tricks that skip generation entirely.

Jev Repos & SDKs#open-models#research#local

Read article

Back to all resources

From the Jev community

Posts from builders shipping with Jev right now.

Follow @typesafeai