Local InferenceOpen SourceFreeActiveLocal hardware· intermediate · ~20 min setup
Guaranteed JSON from Local LLMs with Outlines
Force valid, schema-conformant JSON out of any local model.
Run this workflow
See exactly what it produces before you build it.
Intended Use
Anyone using local LLMs for tool-calling or pipeline outputs where the next step requires valid JSON.
Not for
- Free-form chat responses
- Code generation (different constraint model)
The Stack
Tested Against
outlines@0.1.xollama@0.5Side effects & data flow
- Network
- none, local only
- Writes
- no filesystem writes
- Credentials
- none required
Steps
- 1
Constrain generation
Define a Pydantic schema and let Outlines guarantee the output shape.
from outlines import models, generate from pydantic import BaseModel class Person(BaseModel): name: str age: int model = models.transformers('deepseek-v4') generator = generate.json(model, Person) result = generator('Generate a person')
Eval, 1 fixture
Last passed: verified 10d agoschema-conformancerubrictimeout 60s · max $0Judge: heuristic-json-validate Rubric: Pass if the output parses as JSON AND has exactly the keys 'name' (string) and 'age' (integer).