title: Stream JSON Lines
description: Stream validated JSON responses line-by-line in JustAPI with stream_json.
keywords: [JustAPI, stream JSON, SSE, streaming, NDJSON, validated streaming]

Basic Streaming

Use stream_json to send validated JSON lines:

from justapi import JustAPIApp, Schema
from typing import AsyncGenerator

class Token(Schema):
    text: str
    index: int

app = JustAPIApp()

@app.stream_json("/stream", schema=Token, mode="ndjson")
async def stream_tokens():
    for i, word in enumerate(["Hello", "world", "from", "JustAPI"]):
        yield Token(text=word, index=i)

Each line is validated against the schema before sending.

Mode

With Dependencies

@app.stream_json(
    "/stream",
    schema=Token,
    dependencies=[Depends(get_current_user)],
)
async def stream_tokens(user: dict):
    for i, word in enumerate(["Hello", "world"]):
        yield Token(text=word, index=i)

See Also

• Streaming Output — advanced streaming
• Server-Sent Events — SSE basics
• Validated Streaming — schema validation