Benchmarks
One core of an Apple M3 Pro, Python 3.13, 64 keep-alive connections, median of three 5-second runs per rung. Every number comes from a JSON file under bench/baseline/ in the repository; this page is generated from those files.
Where things stand
Microseconds per request and requests per second, one core; lower microseconds is better. The first column is the day-one ladder run of FastAPI 0.141 on uvicorn, the other two are the current tree.
| Route | FastAPI 0.141 day one, uvicorn | notslowapi, uvicorn | notslowapi, granian |
|---|---|---|---|
| raw ASGI app | 13.7 µs73,040 req/s | 13.2 µs75,943 req/s | 7.9 µs126,946 req/s |
| Starlette route | 19.5 µs51,183 req/s | 15.6 µs63,909 req/s | 8.3 µs120,782 req/s |
| Starlette, int path + str query | not measured | 18.0 µs55,521 req/s | not measured |
| notslowapi, typed dict return | 31.2 µs32,033 req/s | 15.7 µs63,757 req/s | 8.1 µs123,416 req/s |
| notslowapi, untyped dict return | not measured | 15.5 µs64,352 req/s | not measured |
| notslowapi, route via include_router | not measured | 15.4 µs65,132 req/s | 8.3 µs120,761 req/s |
| Starlette, 50 routes | not measured | 15.4 µs65,013 req/s | not measured |
| notslowapi, 50 routes | not measured | 15.3 µs65,489 req/s | not measured |
| notslowapi, 50 routes via include_router | not measured | 15.2 µs65,887 req/s | 8.3 µs120,211 req/s |
| notslowapi, int path + str query | 57.0 µs17,531 req/s | 17.0 µs58,977 req/s | 8.8 µs113,996 req/s |
| notslowapi, pydantic body + response_model | 52.1 µs19,212 req/s | 18.0 µs55,692 req/s | 12.4 µs80,445 req/s |
Rungs added after day one show as not measured in the first column. Single-core numbers; multi-core scaling needs a separate client machine. Source files: results_ladder_v1.json and results_ladder_v3.json.
Every change, measured before and after
Each row is one committed change, measured in the same session with the previous tree checked out for the before run. Rungs not touched by a change are controls. A dot marks a rung that got faster.
| change | rung | before µs | after µs | delta |
|---|---|---|---|---|
| fix1 | l1b_starlette_params | 25.3 | 22.4 | -12% |
| fix1 | l2_fastapi_dict | 31.2 | 30.7 | -2% |
| fix1 | l3_fastapi_params | 50.7 | 35.3 | -30% |
| fix2 | l2_fastapi_dict | 31.0 | 26.3 | -15% |
| fix2 | l3_fastapi_params | 36.2 | 32.6 | -10% |
| fix2 | l4_fastapi_model | 42.7 | 36.7 | -14% |
| fix5 | l2_fastapi_dict | 25.7 | 24.6 | -4% |
| fix5 | l2c_fastapi_included | 29.2 | 27.2 | -7% |
| fix5 | l3_fastapi_params | 31.6 | 29.7 | -6% |
| fix5 | l4_fastapi_model | 36.5 | 32.3 | -11% |
| fix6 | l1_starlette | 19.5 | 19.4 | -0% |
| fix6 | l1b_starlette_params | 21.5 | 22.3 | +4% |
| fix6 | l2_fastapi_dict | 24.6 | 23.8 | -3% |
| fix7 | l4_fastapi_model | 32.3 | 31.5 | -3% |
| fix7 | l2_fastapi_dict | 23.8 | 22.7 | -4% |
| fix8 | l1_starlette | 19.4 | 18.6 | -4% |
| fix8 | l1b_starlette_params | 22.3 | 21.6 | -3% |
| fix8 | l2_fastapi_dict | 22.7 | 22.7 | -0% |
| fix9 | l3_fastapi_params | 29.7 | 27.5 | -7% |
| fix9 | l4_fastapi_model | 31.5 | 30.4 | -4% |
| fix9 | l2_fastapi_dict | 22.7 | 22.0 | -3% |
| fix10 | l1_starlette | 17.9 | 18.3 | +2% |
| fix10 | l2_fastapi_dict | 21.8 | 21.3 | -2% |
| fix10 | l1c_starlette_50routes | 26.7 | 20.5 | -23% |
| fix10 | l5_fastapi_50routes | 36.3 | 25.2 | -31% |
| fix11 | l2c_fastapi_included | 28.7 | 26.8 | -7% |
| fix11 | l5_fastapi_50routes | 31.9 | 25.1 | -21% |
| fix11 | l5b_fastapi_50routes_included | 92.2 | 31.7 | -66% |
| fix12 | l2c_fastapi_included | 26.8 | 23.1 | -14% |
| fix12 | l5_fastapi_50routes | 25.1 | 25.1 | -0% |
| fix12 | l5b_fastapi_50routes_included | 31.7 | 29.8 | -6% |
| fix13 | l1_starlette | 18.6 | 18.0 | -3% |
| fix13 | l1b_starlette_params | 21.7 | 21.0 | -3% |
| fix13 | l2_fastapi_dict | 21.6 | 21.0 | -3% |
| fix14 | l2_fastapi_dict | 21.6 | 20.8 | -4% |
| fix14 | l4_fastapi_model | 30.6 | 28.0 | -8% |
| fix14 | l4_fastapi_model[granian] | 28.4 | 25.1 | -12% |
| fix15_16 | l1_starlette | 17.5 | 17.0 | -3% |
| fix15_16 | l2_fastapi_dict | 20.5 | 18.4 | -10% |
| fix15_16 | l3_fastapi_params | 26.1 | 25.3 | -3% |
| fix15_16 | l2_fastapi_dict[granian] | 10.7 | 9.2 | -13% |
| fix15 | l2_fastapi_dict | 20.5 | 22.6 | +11% |
| fix15 | l3_fastapi_params | 26.6 | 24.7 | -7% |
| fix15 | l2_fastapi_dict[granian] | 14.0 | 10.6 | -24% |
| fix17 | l2_fastapi_dict | 18.9 | 18.2 | -3% |
| fix17 | l3_fastapi_params | 25.4 | 24.9 | -2% |
| fix17 | l4_fastapi_model | 27.2 | 26.8 | -2% |
| fix17 | l2_fastapi_dict[granian] | 9.4 | 9.9 | +6% |
| fix18 | l2_fastapi_dict | 19.4 | 18.9 | -2% |
| fix18 | l3_fastapi_params | 26.1 | 25.1 | -4% |
| fix18 | l2_fastapi_dict[granian] | 10.5 | 12.6 | +20% |
| fix19 | l2_fastapi_dict | 18.4 | 18.0 | -2% |
| fix19 | l3_fastapi_params | 24.8 | 24.6 | -1% |
| fix19 | l2_fastapi_dict[granian] | 10.0 | 10.0 | +0% |
| fix20 | l1_starlette | 17.2 | 16.9 | -2% |
| fix20 | l2_fastapi_dict | 17.8 | 17.1 | -4% |
| fix20 | l5_fastapi_50routes | 21.8 | 21.6 | -1% |
| fix20 | l2_fastapi_dict[granian] | 8.7 | 8.9 | +2% |
| fix21 | l1_starlette | 17.5 | 16.8 | -4% |
| fix21 | l2b_fastapi_untyped | 20.7 | 20.6 | -1% |
| fix21 | l1_starlette[granian] | 10.2 | 9.4 | -9% |
| fix22 | l2_fastapi_dict | 17.2 | 17.0 | -1% |
| fix22 | l2b_fastapi_untyped | 20.3 | 18.0 | -11% |
| fix23 | l1b_starlette_params | 20.1 | 18.3 | -9% |
| fix23 | l3_fastapi_params | 24.8 | 22.4 | -10% |
| fix23 | l3_fastapi_params[granian] | 14.5 | 12.3 | -15% |
| fix24 | l2_fastapi_dict | 18.3 | 18.6 | +1% |
| fix24 | l4_fastapi_model | 26.7 | 22.1 | -17% |
| fix24 | l4_fastapi_model[granian] | 21.4 | 15.7 | -27% |
| fix25 | l1b_starlette_params | 20.1 | 19.2 | -4% |
| fix25 | l2_fastapi_dict | 19.1 | 19.1 | -0% |
| fix25 | l3_fastapi_params | 23.2 | 23.0 | -1% |
| fix25 | l3_fastapi_params[granian] | 14.8 | 13.5 | -8% |
| fix26 | l2_fastapi_dict | 17.7 | 17.5 | -1% |
| fix26 | l2c_fastapi_included | 21.0 | 18.3 | -13% |
| fix26 | l5b_fastapi_50routes_included | 26.6 | 20.6 | -22% |
| fix26 | l5b_fastapi_50routes_included[granian] | 17.5 | 10.7 | -39% |
| fix27 | l2_fastapi_dict | 17.5 | 17.6 | +1% |
| fix27 | l1c_starlette_50routes | 19.7 | 16.9 | -15% |
| fix27 | l5_fastapi_50routes | 22.1 | 18.3 | -17% |
| fix27 | l5b_fastapi_50routes_included | 26.3 | 21.2 | -19% |
| fix28 | l0_raw | 13.5 | 13.5 | -0% |
| fix28 | l2_fastapi_dict | 17.5 | 17.2 | -2% |
| fix28 | l3_fastapi_params | 22.4 | 22.0 | -2% |
| fix28 | l2_fastapi_dict[granian] | 9.2 | 8.9 | -3% |
| fix28 | l3_fastapi_params[granian] | 11.9 | 11.3 | -5% |
| fix29 | l0_raw | 14.2 | 14.3 | +0% |
| fix29 | l2_fastapi_dict | 17.9 | 16.6 | -7% |
| fix29 | l2b_fastapi_untyped | 18.9 | 18.3 | -3% |
| fix29 | l2_fastapi_dict[granian] | 9.9 | 9.1 | -8% |
| fix30 | l0_raw | 14.7 | 14.3 | -3% |
| fix30 | l2_fastapi_dict | 17.5 | 16.6 | -5% |
| fix30 | l3_fastapi_params | 22.7 | 21.7 | -4% |
| fix30 | l3_fastapi_params[granian] | 13.1 | 16.5 | +27% |
| fix31 | l0_raw | 14.5 | 15.5 | +7% |
| fix31 | l2_fastapi_dict | 16.6 | 16.8 | +1% |
| fix31 | l2b_fastapi_untyped | 18.4 | 17.1 | -7% |
| fix33 | l0_raw | 14.5 | 14.4 | -1% |
| fix33 | l2_fastapi_dict | 16.6 | 16.7 | +0% |
| fix33 | l3_fastapi_params | 21.4 | 18.9 | -12% |
| fix33 | l3_fastapi_params[granian] | 11.4 | 10.0 | -12% |
| fix34 | l0_raw | 13.9 | 13.5 | -3% |
| fix34 | l3_fastapi_params | 18.6 | 18.0 | -3% |
| fix34 | l6_fastapi_depends | 38.1 | 28.9 | -24% |
| fix34 | l6_fastapi_depends[granian] | 29.6 | 19.8 | -33% |
| fix35 | l0_raw | 13.6 | 13.5 | -1% |
| fix35 | l6_fastapi_depends | 29.0 | 27.3 | -6% |
| fix35 | l6_fastapi_depends[granian] | 19.5 | 18.1 | -7% |
| fix36 | l0_raw | 13.6 | 13.6 | +0% |
| fix36 | l6_fastapi_depends | 27.1 | 25.8 | -5% |
| fix36 | l6_fastapi_depends[granian] | 17.7 | 16.1 | -9% |
| fix37 | l0_raw | 13.9 | 13.7 | -1% |
| fix37 | l3_fastapi_params | 19.0 | 18.4 | -3% |
| fix37 | l6_fastapi_depends | 25.9 | 25.0 | -3% |
| fix37 | l6_fastapi_depends[granian] | 16.4 | 15.0 | -9% |
| fix38 | l0_raw | 13.6 | 14.0 | +3% |
| fix38 | l2_fastapi_dict | 15.8 | 15.8 | +0% |
| fix38 | l4_fastapi_model | 21.2 | 19.3 | -9% |
| fix38 | l4_fastapi_model[granian] | 14.6 | 13.1 | -10% |
| fix39 | l0_raw | 13.4 | 13.5 | +0% |
| fix39 | l1_starlette | 16.9 | 16.3 | -4% |
| fix39 | l1b_starlette_params | 18.7 | 17.8 | -5% |
| fix39 | l1c_starlette_50routes | 16.8 | 16.3 | -3% |
| fix39 | l1_starlette[granian] | 8.8 | 9.5 | +7% |
| fix40 | l0_raw | 14.0 | 13.7 | -2% |
| fix40 | l6_fastapi_depends | 25.0 | 24.8 | -1% |
| fix40 | l6_fastapi_depends[granian] | 15.6 | 14.7 | -6% |
| fix41 | l0_raw | 13.4 | 13.7 | +2% |
| fix41 | l3_fastapi_params | 18.3 | 17.7 | -3% |
| fix41 | l6_fastapi_depends | 25.0 | 23.3 | -7% |
| fix41 | l3_fastapi_params[granian] | 9.3 | 9.0 | -2% |
| fix41 | l6_fastapi_depends[granian] | 14.5 | 13.0 | -11% |
| fix43 | l6_fastapi_depends | 23.2 | 21.4 | -8% |
| fix43 | l3_fastapi_params[granian] | 10.3 | 10.4 | +1% |
| fix43 | l6_fastapi_depends[granian] | 13.5 | 12.3 | -9% |
| fix44 | l2c_fastapi_included | 17.6 | 17.3 | -2% |
| fix44 | l2_fastapi_dict[granian] | 9.2 | 9.2 | +1% |
| fix44 | l2c_fastapi_included[granian] | 10.4 | 9.3 | -11% |
| fix44 | l5b_fastapi_50routes_included[granian] | 9.7 | 9.3 | -3% |
Method
The ladder isolates layers: a raw ASGI app, a Starlette route, then notslowapi routes of increasing complexity, all under the same server flags. Load comes from oha; the native split between interpreter and kernel comes from sample(1); Python-level attribution from pyinstrument started in the ASGI lifespan. Surprising numbers are re-measured in alternating after, before, after runs before they count. Details in the docs.