Get started

From zero to your first Jev request you need exactly two things: an API key and an HTTP client.

1. Register and get an API key

1. Sign up at console.typesafe.ai (Jev launched on 2026-09-15 behind a waitlist; media reports say the waitlist was removed on 9/21)
2. Create an API key in the console
3. Store it in an environment variable — never in code or in a browser:

Terminal

export TYPESAFE_API_KEY="tsf_..."   # format shown for illustration only

Key handling

This site never displays or holds real keys. All examples read from environment variables, and an API key must never appear in browser code — proxy frontend calls through your own backend. See the simulated mode in the JavaScript guide and Python guide.

2. Send your first request

curl

curl https://api.typesafe.ai/v1/systemone \
  -H "Authorization: Bearer $TYPESAFE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "jev-latest",
    "state": "It kept raining all day and the match was cancelled.",
    "questions": {
      "mood": {
        "type": "choice",
        "instructions": "The overall mood of the sentence",
        "criteria": { "positive": "happy or hopeful", "negative": "sad or angry", "neutral": "neither" }
      }
    }
  }'

Response (structure per the official docs; values illustrative):

{
  "model": "jev-1.13.0",
  "answers": {
    "mood": {
      "type": "choice",
      "choice": "negative",
      "probabilities": { "negative": 0.9, "neutral": 0.1, "positive": 0.0 },
      "confidence": 0.8
    }
  },
  "usage": { "input_tokens": 60, "output_tokens": 5 }
}

Field-by-field: the API reference. Question types: Capabilities.

3. Which model name to use

Official models page (verified 2026-09-22):

Name	Purpose
jev-latest	Stable latest (recommended default)
jev-preview	Preview (early access, may change)
jev-1.13.0	Pinned version (reproducible experiments)

4. Free credit and pricing

• Pricing (official): input $0.042 per million tokens, output free — one dollar buys roughly 24M input tokens
• Free credit: multiple outlets (36kr among them) report $5 on sign-up (~120M tokens). Not verified by this site — whatever your console shows after sign-up is the truth
• There are no local weights to run; for offline experiments look at community replicas (Ecosystem) — which are not Jev itself

5. When things go wrong

401 invalid key → check the env var; 422 invalid request → diff against the schema; 429 rate limited → back off and retry; 529 overloaded → retry with backoff. Full error handling and SDK retry configuration: API reference.

Next steps

• Real code with the official SDKs: JavaScript · Python
• Pick a pattern to practice: Use cases