# AN-2026-0796: Starlette 1.0 (Mar 22, 2026) removed @app.route, @app.websocket_route, @app.middleware and @app.exception_handler decorators and the TemplateResponse(name, context) signature

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- id: AN-2026-0796 (version 1; cite https://breakwire.org/claim/AN-2026-0796/v/1)
- kind: breaking · status: active · review: editor
- source: <https://starlette.dev/release-notes/#:~:text=Starlette%201.0%20is%20here>
- more sources: <https://github.com/Kludex/starlette/blob/1.10.0/docs/release-notes.md#L229> <https://pypi.org/project/starlette/1.0.0/>
- event date: 2026-03-22
- services: starlette, python
- affected: pypi:starlette >=1.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Starlette release notes (opened 2026-11-04), 1.0.0rc1 Removed (#3117, #3118, #3147): @app.route() (use Route in routes), @app.websocket_route() (use WebSocketRoute), @app.exception_handler() (use the exception_handlers parameter), @app.middleware() (use the middleware parameter), iscoroutinefunction_or_partial() from starlette.routing, **env_options on Jinja2Templates (pass a preconfigured jinja2.Environment via env), the deprecated TemplateResponse(name, context) signature (use TemplateResponse  [✓0 ✗0]
1. The 1.0.0rc1 notes say Starlette is the foundation of FastAPI and a dependency of the Python MCP SDK; FastAPI keeps its own decorators (app.get/post, app.middleware, app.exception_handler), so this mainly breaks plain Starlette apps and code that subclasses Starlette.  [✓0 ✗0]
2. Reproduced 2026-11-04 with starlette 1.10.0: @app.route / @app.middleware / @app.exception_handler on a Starlette app raise AttributeError "'Starlette' object has no attribute 'route'" (resp. 'middleware', 'exception_handler'); Jinja2Templates(directory=..., autoescape=False) raises TypeError "Jinja2Templates.__init__() got an unexpected keyword argument 'autoescape'"; TemplateResponse('i.html', {'request': req}) raises TypeError "unhashable type: 'dict'".  [✓0 ✗0]

## Fix
```text
Declare routes up front: `Starlette(routes=[Route('/', endpoint), WebSocketRoute('/ws', ws)], middleware=[Middleware(Cls)], exception_handlers={404: handler})`. Templates: `templates.TemplateResponse(request, 'page.html', {...})`; for Jinja options build `jinja2.Environment(...)` and pass `Jinja2Templates(env=env)`. Or pin `starlette<1.0` until migrated.
```

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## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (FastAPI release notes + 0.162.0 source, Starlette release notes + 1.10.0 source; messages reproduced on fastapi 0.162.0 / starlette 1.10.0)