Performance

Titanium targets low-overhead MITM proxying: connection pooling, HTTP/2 multiplexing, and buffer reuse. Numbers below are Release measurements with RpsLoadProbe (and BenchmarkDotNet / Basic example where noted). Publishable tables cite GitHub Actions medians on matched 4 vCPU / 16 GiB runners. Absolute RPS still varies by OS kernel, TLS, and MsQuic packaging — compare within a table, not across Windows vs Linux.

Control arms: nginx (native C reverse-proxy ceiling; Linux is authoritative) and YARP (Yarp.ReverseProxy, managed .NET reverse proxy). Neither can MITM (no CONNECT / forged certs). FiddlerCore is not compared (commercial debugger license; not a throughput peer).

For pooling knobs and certificate first-visit tuning, see Performance and pooling. For the local cool A/B lab, laptop tables, and profiling notes, see Performance Profiling.

Measurement environment

Both OS use the standard public-repo GitHub-hosted runner class (4 vCPU / 16 GiB / 14 GB SSD). Same harness knobs (workflow_dispatch RPS saturation: warmup 2s / measure 8s; concurrency 8, 16, 32, 64; median of 3 repeats). Every --ramp arm is three OS processes (parent load generator + origin child + proxy child), except origin-direct arms (load gen + origin only). Prefer TWP÷YARP / TWP÷nginx ratios over absolute RPS.

Laptop High-perf / cool-paired Windows numbers live on Performance Local Lab. Do not mix those absolutes into the tables below.

Windows (GitHub-hosted `windows-latest`)


OS	Windows Server (GitHub-hosted `windows-latest`)
CPU	4 logical processors
RAM	16 GiB
Runtime	.NET 10.0.x
nginx	nginx/Windows 1.31.3 (same-OS only; no QUIC)
YARP	Yarp.ReverseProxy 2.3.0
Harness	RpsLoadProbe Release; median of 3 repeats

Linux (GitHub-hosted `ubuntu-latest`)


OS	Ubuntu 24.04.x LTS
CPU	4 logical processors (AMD EPYC; runners this pass were 7763 / 9V74)
RAM	16 GiB
Runtime	.NET 10.0.11
nginx	nginx/1.31.4 (nginx.org mainline, `--with-http_v3_module`)
YARP	Yarp.ReverseProxy 2.3.0
Harness	RpsLoadProbe Release; median of 3 repeats where noted

Saturation control

Calibration for the shared 4 vCPU loopback shape: how close client + origin are to saturated before ranking reverse peers. Tiny keep-alive GET. Median of 3 repeats @ f9769503 — 32737672381. Warmup 2s / measure 8s; concurrency 8, 16, 32, 64. Block A % of origin-HttpClient uses median peak RPS. Blocks B/C use peer÷YARP / ÷nginx on median peak (not % of H1 origin). RPS cells embed median RSS / CPU for the proxy child plus its full descendant tree (serve-proxy → nginx master → workers); origin-direct samples the origin child. Product matrices below use matched dotnet-httpclient only (not bombardier). H3→H1 after inbound H3 Http2PendingWork (unroot completed stream tasks): Win Block C TWP RSS 112 MiB vs YARP 141 (0.79×); Linux 140 vs 182 (0.77×). RPS still leads YARP (1.12× / 1.07×).

pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-saturation

Block A — H1 plain

Arm	Generator	Notes
`origin-direct`	`dotnet-httpclient`	No proxy — origin ceiling under the same client used for publishable ratios
`origin-direct-bombardier`	`bombardier`	External client check (CI installs bombardier)
`bare-reverse-http1`	`dotnet-httpclient`	Thin C# H1 reverse (`BareHttp1ReverseProxy`) — .NET runtime / loopback ceiling for a three-process reverse hop; not a product peer
`nginx-reverse-http1` / `yarp-reverse-http1` / `twp-reverse-http1`	`dotnet-httpclient`	Product peers (medals among these three only)

Windows (windows-latest)

Arm	Generator	Sustain	Peak	% of origin-HttpClient
origin-direct	dotnet-httpclient	75,458 _{(53 MiB / 42.1% CPU)}	75,697 _{(53 MiB / 42.1% CPU)}	100%
origin-direct-bombardier	bombardier	57,354 _{(54 MiB / 30.4% CPU)}	57,354 _{(54 MiB / 30.4% CPU)}	75.8%
bare-reverse-http1	dotnet-httpclient	37,781 _{(55 MiB / 44.5% CPU)}	37,781 _{(55 MiB / 44.5% CPU)}	49.9%
nginx-reverse-http1	dotnet-httpclient	27,698 _{(120 MiB / 24.8% CPU)}	28,702 _{(120 MiB / 24.8% CPU)}	37.9%
yarp-reverse-http1	dotnet-httpclient	33,984 _{(87 MiB / 47.8% CPU)}	33,984 _{(87 MiB / 47.8% CPU)}	44.9%
twp-reverse-http1	dotnet-httpclient	🥇 37,305 _{(73 MiB / 48.1% CPU)}	37,305 _{(73 MiB / 48.1% CPU)}	49.3%

Linux (ubuntu-latest)

Arm	Generator	Sustain	Peak	% of origin-HttpClient
origin-direct	dotnet-httpclient	80,190 _{(78 MiB / 43.7% CPU)}	80,190 _{(78 MiB / 43.7% CPU)}	100%
origin-direct-bombardier	bombardier	47,967 _{(79 MiB / 37.4% CPU)}	47,967 _{(79 MiB / 37.4% CPU)}	59.8%
bare-reverse-http1	dotnet-httpclient	35,466 _{(66 MiB / 45.8% CPU)}	35,466 _{(66 MiB / 45.8% CPU)}	44.2%
nginx-reverse-http1	dotnet-httpclient	🥇 43,639 _{(71 MiB / 40.6% CPU)}	43,639 _{(71 MiB / 40.6% CPU)}	54.4%
yarp-reverse-http1	dotnet-httpclient	31,718 _{(116 MiB / 48.6% CPU)}	31,718 _{(116 MiB / 48.6% CPU)}	39.6%
twp-reverse-http1	dotnet-httpclient	36,725 _{(85 MiB / 49.7% CPU)}	36,725 _{(85 MiB / 49.7% CPU)}	45.8%

Reverse peers are about 38–54% of the origin-direct HttpClient peak on this runner class. Prefer the % column over absolute RPS across runs. Bare and origin-direct are controls (not medal peers).

Block B — H2 TLS→H1

Peer ratios (÷YARP / ÷nginx) on median peak; RPS cells embed (MiB / CPU%).

Windows (windows-latest)

Arm	Generator	Sustain	Peak	÷YARP	÷nginx
nginx-reverse-http2	dotnet-httpclient	22,708 _{(137 MiB / 23.6% CPU)}	22,708 _{(137 MiB / 23.6% CPU)}	0.53×	1.00×
yarp-reverse-http2	dotnet-httpclient	43,028 _{(92 MiB / 50.3% CPU)}	43,028 _{(92 MiB / 50.3% CPU)}	1.00×	1.89×
twp-reverse-http2-cleartext	dotnet-httpclient	🥇 45,107 _{(101 MiB / 50.7% CPU)}	45,107 _{(101 MiB / 50.7% CPU)}	1.05×	1.99×

Linux (ubuntu-latest)

Arm	Generator	Sustain	Peak	÷YARP	÷nginx
nginx-reverse-http2	dotnet-httpclient	16,510 _{(95 MiB / 22.7% CPU)}	22,691 _{(95 MiB / 22.7% CPU)}	0.67×	1.00×
yarp-reverse-http2	dotnet-httpclient	34,054 _{(120 MiB / 48.3% CPU)}	34,054 _{(120 MiB / 48.3% CPU)}	1.00×	1.50×
twp-reverse-http2-cleartext	dotnet-httpclient	🥇 38,619 _{(118 MiB / 51.8% CPU)}	38,619 _{(118 MiB / 51.8% CPU)}	1.13×	1.70×

Block C — H3→H1

Same layout as Block B. Requires QuicListener; nginx only with http_v3_module (Windows nginx has no QUIC).

Windows (windows-latest)

Arm	Generator	Sustain	Peak	÷YARP	÷nginx
nginx-reverse-http3-cleartext	dotnet-httpclient	Not possible (no QUIC)	Not possible	—	—
yarp-reverse-http3-cleartext	dotnet-httpclient	20,754 _{(141 MiB / 48.1% CPU)}	20,754 _{(141 MiB / 48.1% CPU)}	1.00×	—
twp-reverse-http3-cleartext	dotnet-httpclient	🥇 23,323 _{(112 MiB / 41.7% CPU)}	23,323 _{(112 MiB / 41.7% CPU)}	1.12×	—

Linux (ubuntu-latest)

Arm	Generator	Sustain	Peak	÷YARP	÷nginx
nginx-reverse-http3-cleartext	dotnet-httpclient	0 _{(104 MiB / 21.9% CPU)}	18,938 _{(104 MiB / 21.9% CPU)}	0.87×	1.00×
yarp-reverse-http3-cleartext	dotnet-httpclient	21,690 _{(182 MiB / 48.8% CPU)}	21,690 _{(182 MiB / 48.8% CPU)}	1.00×	1.15×
twp-reverse-http3-cleartext	dotnet-httpclient	🥇 23,118 _{(140 MiB / 51.4% CPU)}	23,118 _{(140 MiB / 51.4% CPU)}	1.07×	1.22×

How to read the tables

Mode: Reverse = transparent fixed-forward (may TLS-terminate to a cleartext origin, or re-encrypt to a configured HTTPS/QUIC origin). MITM = both legs are visible in the clear inside TWP — either by decrypting client TLS/QUIC (forged cert / CONNECT) or by accepting an already-cleartext client (explicit HTTP proxy / inspectable transparent reverse) while still speaking plain or TLS to the origin. nginx and YARP cannot do MITM. HTTP/3 has no cleartext client (QUIC always encrypted).
Sustainable = last concurrency that still met error/latency SLOs. Peak = highest RPS in that ramp.
🥇 = best among TWP / nginx / YARP only on that row or saturation block (never vs bare / origin-direct / bombardier). Product matrices and saturation Sustain: highest sustainable RPS. Saturation RPS cells embed (MiB / CPU%); 🥇 for Memory/CPU is omitted (footprint is informational). Omitted when only TWP can run the path (no fair multi-product comparison).
Not possible = product cannot do that path. Not measured = path exists but no published number yet for that OS.

pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-same
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-terminate
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-bridges
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-mitm
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-bodies
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-post
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-lossy
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-tls-cost
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-arch
pwsh tools/RpsLoadProbe/run-rps.ps1 -Mode compare-saturation

Windows — Titanium vs nginx vs YARP

Client / origin: HTTP version and whether TLS is used (plain = cleartext, TLS = encrypted, QUIC = HTTP/3).

Median of 3 repeats on windows-latest (4 vCPU / 16 GiB). Saturation @ f9769503 — 32737672381; bridges 32737668291. Three-process harness, parent-seeded loopback CA. Warmup 2s / measure 8s; concurrency 8, 16, 32, 64. Prefer TWP÷peer ratios over absolute RPS. RPS cells include median RSS / CPU at the peak-RPS step as <br><sub>(MiB / CPU%)</sub> for TWP, nginx, and YARP (proxy child + descendant tree). Bridge / H3→H1 Memory after inbound H3 Http2PendingWork + prior ClientSyntheticStreams. H1 plain / terminate / MITM rows below are still the prior paste (no compare-same / compare-mitm this pass). Laptop High-perf / cool-paired numbers stay on the local lab.

Load generators: Reverse inbound H3 arms use dotnet-httpclient (http_version=3.0, RequestVersionExact). nginx/Windows is same-OS only (no QUIC).

Mode	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Reverse	HTTP/1 · plain	HTTP/1 · plain	🥇 25,525 _{(76 MiB / 52.9% CPU)}	25,525 _{(76 MiB / 52.9% CPU)}	13,325 _{(120 MiB / 24.8% CPU)}	13,325 _{(120 MiB / 24.8% CPU)}	21,341 _{(88 MiB / 49.6% CPU)}	21,341 _{(88 MiB / 49.6% CPU)}
Reverse	HTTP/1 · plain	HTTP/1 · TLS	🥇 21,069 _{(84 MiB / 52% CPU)}	21,069 _{(84 MiB / 52% CPU)}	Not possible	Not possible	19,498 _{(100 MiB / 52.2% CPU)}	19,498 _{(100 MiB / 52.2% CPU)}
Reverse	HTTP/1 · TLS	HTTP/1 · plain	🥇 20,286 _{(82 MiB / 50.5% CPU)}	20,286 _{(82 MiB / 50.5% CPU)}	8,980 _{(137 MiB / 24.9% CPU)}	8,980 _{(137 MiB / 24.9% CPU)}	17,956 _{(103 MiB / 50.6% CPU)}	17,956 _{(103 MiB / 50.6% CPU)}
Reverse	HTTP/1 · TLS	HTTP/2 · TLS	🥇 41,099 _{(121 MiB / 48.2% CPU)}	41,099 _{(121 MiB / 48.2% CPU)}	Not possible	Not possible	40,363 _{(108 MiB / 48% CPU)}	40,363 _{(108 MiB / 48% CPU)}
Reverse	HTTP/1 · TLS	HTTP/3 · QUIC	24,579 _{(113 MiB / 50.9% CPU)}	24,579 _{(113 MiB / 50.9% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	🥇 24,610 _{(127 MiB / 51.2% CPU)}	24,610 _{(127 MiB / 51.2% CPU)}
Reverse	HTTP/2 · plain	HTTP/1 · plain	🥇 54,965 _{(92 MiB / 51.3% CPU)}	54,965 _{(92 MiB / 51.3% CPU)}	Not possible	Not possible	51,379 _{(84 MiB / 49.3% CPU)}	51,379 _{(84 MiB / 49.3% CPU)}
Reverse	HTTP/2 · plain	HTTP/2 · plain	🥇 123,474 _{(72 MiB / 34.8% CPU)}	123,474 _{(72 MiB / 34.8% CPU)}	Not possible	Not possible	90,820 _{(95 MiB / 50.2% CPU)}	90,820 _{(95 MiB / 50.2% CPU)}
Reverse	HTTP/2 · plain	HTTP/2 · TLS	🥇 73,711 _{(81 MiB / 35.1% CPU)}	73,711 _{(81 MiB / 35.1% CPU)}	Not possible	Not possible	55,888 _{(97 MiB / 46.5% CPU)}	55,888 _{(97 MiB / 46.5% CPU)}
Reverse	HTTP/2 · plain	HTTP/3 · QUIC	🥇 43,005 _{(142 MiB / 52.9% CPU)}	43,005 _{(142 MiB / 52.9% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	41,493 _{(130 MiB / 50.6% CPU)}	41,493 _{(130 MiB / 50.6% CPU)}
Reverse	HTTP/2 · TLS	HTTP/1 · plain	🥇 52,700 _{(100 MiB / 52.7% CPU)}	52,700 _{(100 MiB / 52.7% CPU)}	22,708 _{(137 MiB / 23.6% CPU)}	22,708 _{(137 MiB / 23.6% CPU)}	46,315 _{(91 MiB / 50.9% CPU)}	46,315 _{(91 MiB / 50.9% CPU)}
Reverse	HTTP/2 · TLS	HTTP/2 · plain	🥇 113,697 _{(91 MiB / 36.8% CPU)}	113,697 _{(91 MiB / 36.8% CPU)}	Not possible	Not possible	78,136 _{(101 MiB / 52.1% CPU)}	78,136 _{(101 MiB / 52.1% CPU)}
Reverse	HTTP/2 · TLS	HTTP/3 · QUIC	🥇 42,415 _{(142 MiB / 54.5% CPU)}	42,415 _{(142 MiB / 54.5% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	37,948 _{(128 MiB / 52% CPU)}	37,948 _{(128 MiB / 52% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/1 · plain	🥇 25,956 _{(114 MiB / 45.6% CPU)}	25,956 _{(114 MiB / 45.6% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	25,323 _{(166 MiB / 49.3% CPU)}	25,323 _{(166 MiB / 49.3% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/2 · TLS	🥇 35,712 _{(128 MiB / 47.8% CPU)}	35,712 _{(128 MiB / 47.8% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	32,975 _{(180 MiB / 48.3% CPU)}	32,975 _{(180 MiB / 48.3% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/3 · QUIC	🥇 14,981 _{(173 MiB / 47.7% CPU)}	14,981 _{(173 MiB / 47.7% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	11,620 _{(165 MiB / 51.7% CPU)}	11,620 _{(165 MiB / 51.7% CPU)}
MITM	HTTP/1 · plain	HTTP/1 · plain	🥇 33,785 _{(78 MiB / 51.9% CPU)}	33,785 _{(78 MiB / 51.9% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · plain	HTTP/1 · TLS	🥇 30,763 _{(97 MiB / 51.2% CPU)}	30,763 _{(97 MiB / 51.2% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/1 · plain	🥇 30,785 _{(89 MiB / 49.6% CPU)}	30,785 _{(89 MiB / 49.6% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/2 · TLS	🥇 37,519 _{(114 MiB / 49.5% CPU)}	37,519 _{(114 MiB / 49.5% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/3 · QUIC	🥇 20,160 _{(114 MiB / 52% CPU)}	20,160 _{(114 MiB / 52% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/1 · plain	🥇 45,273 _{(190 MiB / 50.7% CPU)}	45,273 _{(190 MiB / 50.7% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/2 · plain	🥇 91,446 _{(73 MiB / 35.5% CPU)}	91,446 _{(73 MiB / 35.5% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/2 · TLS	🥇 82,967 _{(87 MiB / 37.1% CPU)}	82,967 _{(87 MiB / 37.1% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/3 · QUIC	🥇 33,186 _{(191 MiB / 54% CPU)}	33,186 _{(191 MiB / 54% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/1 · plain	🥇 43,911 _{(182 MiB / 54.6% CPU)}	43,911 _{(182 MiB / 54.6% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/2 · plain	🥇 86,099 _{(93 MiB / 39% CPU)}	86,099 _{(93 MiB / 39% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/3 · QUIC	🥇 32,660 _{(184 MiB / 53.4% CPU)}	32,660 _{(184 MiB / 53.4% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/1 · plain	🥇 22,442 _{(241 MiB / 42.4% CPU)}	22,442 _{(241 MiB / 42.4% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/2 · TLS	🥇 27,656 _{(218 MiB / 47.9% CPU)}	27,656 _{(218 MiB / 47.9% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/3 · QUIC	🥇 16,808 _{(215 MiB / 47.2% CPU)}	16,808 _{(215 MiB / 47.2% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · plain (CONNECT)	HTTP/1 · TLS	🥇 27,351 _{(105 MiB / 50.6% CPU)}	27,351 _{(105 MiB / 50.6% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/1 · TLS	🥇 28,338 _{(83 MiB / 48.4% CPU)}	28,338 _{(83 MiB / 48.4% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/2 · TLS	🥇 76,456 _{(89 MiB / 37.1% CPU)}	76,456 _{(89 MiB / 37.1% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/1 · TLS	🥇 39,157 _{(167 MiB / 53.3% CPU)}	39,157 _{(167 MiB / 53.3% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/1 · TLS	🥇 20,318 _{(243 MiB / 41.8% CPU)}	20,318 _{(243 MiB / 41.8% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	Not possible (no MITM)	Not possible (no MITM)

TWP÷YARP bridges @ f9769503: H3→H1 ≈ 1.02× RPS / 0.69× Memory (114 / 166 MiB); H3→H2 ≈ 1.08× / 0.71×; H2 TLS→H1 ≈ 1.14× / 1.10× Memory; H1→H2 ≈ 1.02× / 1.12× Memory. H1→H3 RPS ~tie (1.00×) with Memory win (0.89×). Prefer ratios over absolute RPS on GHA VMs. H1 plain / terminate / MITM rows are prior paste (no compare-same / compare-mitm this pass). nginx/YARP cannot MITM.

Linux — Titanium vs nginx vs YARP

Median of 3 repeats on ubuntu-latest (4 vCPU / 16 GiB). Saturation @ f9769503 (32737672381); bridges 32737668291. Warmup 2s / measure 8s; concurrency 8, 16, 32, 64. Linux nginx is the authoritative nginx baseline. The RPS workflow installs nginx.org mainline (http_v3_module) and libmsquic (QuicListener.IsSupported=true on ubuntu-latest). Prefer ratios over absolute RPS. RPS cells include peer (MiB / CPU%) as on Windows. Bridge / H3→H1 after inbound H3 Http2PendingWork. H1 plain / terminate / MITM rows prior paste (no compare-same / compare-mitm this pass).

TWP÷YARP bridges: H3→H1 ≈ 1.07× RPS / 0.80× Memory (146 / 183 MiB); H3→H2 ≈ 1.06× / 0.75×; H2 TLS→H1 ≈ 1.10× / 0.98×; H1→H2 ≈ 1.03× / 1.08× Memory. H1 plain ÷nginx from prior compare-same ≈ 0.81.

Mode	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Reverse	HTTP/1 · plain	HTTP/1 · plain	46,284 _{(82 MiB / 51.1% CPU)}	46,284 _{(82 MiB / 51.1% CPU)}	🥇 55,862 _{(72 MiB / 41.2% CPU)}	55,862 _{(72 MiB / 41.2% CPU)}	41,203 _{(114 MiB / 49.4% CPU)}	41,203 _{(114 MiB / 49.4% CPU)}
Reverse	HTTP/1 · plain	HTTP/1 · TLS	🥇 37,194 _{(103 MiB / 48.6% CPU)}	37,194 _{(103 MiB / 48.6% CPU)}	Not possible	Not possible	33,500 _{(140 MiB / 49.2% CPU)}	33,500 _{(140 MiB / 49.2% CPU)}
Reverse	HTTP/1 · TLS	HTTP/1 · plain	36,518 _{(107 MiB / 49.1% CPU)}	36,518 _{(107 MiB / 49.1% CPU)}	🥇 43,011 _{(99 MiB / 41.6% CPU)}	43,011 _{(99 MiB / 41.6% CPU)}	32,495 _{(135 MiB / 50% CPU)}	32,495 _{(135 MiB / 50% CPU)}
Reverse	HTTP/1 · TLS	HTTP/2 · TLS	🥇 28,343 _{(156 MiB / 49.8% CPU)}	28,343 _{(156 MiB / 49.8% CPU)}	Not possible	Not possible	27,456 _{(144 MiB / 46.9% CPU)}	27,456 _{(144 MiB / 46.9% CPU)}
Reverse	HTTP/1 · TLS	HTTP/3 · QUIC	🥇 21,375 _{(142 MiB / 52.4% CPU)}	21,375 _{(142 MiB / 52.4% CPU)}	Not possible (no H3 origin)	Not possible (no H3 origin)	19,843 _{(161 MiB / 49.6% CPU)}	19,843 _{(161 MiB / 49.6% CPU)}
Reverse	HTTP/2 · plain	HTTP/1 · plain	🥇 41,502 _{(113 MiB / 52.8% CPU)}	41,502 _{(113 MiB / 52.8% CPU)}	Not possible	Not possible	39,900 _{(115 MiB / 48.3% CPU)}	39,900 _{(115 MiB / 48.3% CPU)}
Reverse	HTTP/2 · plain	HTTP/2 · plain	🥇 74,010 _{(101 MiB / 41.2% CPU)}	74,010 _{(101 MiB / 41.2% CPU)}	Not possible	Not possible	55,978 _{(129 MiB / 46.7% CPU)}	55,978 _{(129 MiB / 46.7% CPU)}
Reverse	HTTP/2 · plain	HTTP/2 · TLS	🥇 51,070 _{(110 MiB / 39.8% CPU)}	51,070 _{(110 MiB / 39.8% CPU)}	Not possible	Not possible	38,998 _{(129 MiB / 45.9% CPU)}	38,998 _{(129 MiB / 45.9% CPU)}
Reverse	HTTP/2 · plain	HTTP/3 · QUIC	🥇 29,622 _{(148 MiB / 50.5% CPU)}	29,622 _{(148 MiB / 50.5% CPU)}	Not possible (no H3 origin)	Not possible (no H3 origin)	28,768 _{(151 MiB / 45.9% CPU)}	28,768 _{(151 MiB / 45.9% CPU)}
Reverse	HTTP/2 · TLS	HTTP/1 · plain	🥇 38,014 _{(118 MiB / 52.2% CPU)}	38,014 _{(118 MiB / 52.2% CPU)}	16,510 _{(95 MiB / 22.7% CPU)}	22,691 _{(95 MiB / 22.7% CPU)}	34,499 _{(120 MiB / 48.7% CPU)}	34,499 _{(120 MiB / 48.7% CPU)}
Reverse	HTTP/2 · TLS	HTTP/2 · plain	🥇 68,135 _{(109 MiB / 40.8% CPU)}	68,135 _{(109 MiB / 40.8% CPU)}	Not possible	Not possible	44,788 _{(124 MiB / 46.5% CPU)}	44,788 _{(124 MiB / 46.5% CPU)}
Reverse	HTTP/2 · TLS	HTTP/3 · QUIC	🥇 28,067 _{(157 MiB / 49.2% CPU)}	28,067 _{(157 MiB / 49.2% CPU)}	Not possible (no H3 origin)	Not possible (no H3 origin)	25,084 _{(155 MiB / 46.2% CPU)}	25,084 _{(155 MiB / 46.2% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/1 · plain	🥇 23,227 _{(146 MiB / 51.8% CPU)}	23,227 _{(146 MiB / 51.8% CPU)}	0 _{(103 MiB / 21.9% CPU)}	18,730 _{(103 MiB / 21.9% CPU)}	21,638 _{(183 MiB / 49.2% CPU)}	21,638 _{(183 MiB / 49.2% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/2 · TLS	🥇 25,529 _{(144 MiB / 53.5% CPU)}	25,529 _{(144 MiB / 53.5% CPU)}	Not possible (no H3→H2)	Not possible (no H3→H2)	24,112 _{(193 MiB / 47% CPU)}	24,112 _{(193 MiB / 47% CPU)}
Reverse	HTTP/3 · QUIC	HTTP/3 · QUIC	🥇 19,341 _{(214 MiB / 47.4% CPU)}	19,341 _{(214 MiB / 47.4% CPU)}	Not possible (no H3 origin)	Not possible (no H3 origin)	15,760 _{(198 MiB / 47.5% CPU)}	15,760 _{(198 MiB / 47.5% CPU)}
MITM	HTTP/1 · plain	HTTP/1 · plain	🥇 56,421 _{(85 MiB / 51.3% CPU)}	56,421 _{(85 MiB / 51.3% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · plain	HTTP/1 · TLS	🥇 46,215 _{(106 MiB / 47.1% CPU)}	46,215 _{(106 MiB / 47.1% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/1 · plain	🥇 46,892 _{(107 MiB / 48.4% CPU)}	46,892 _{(107 MiB / 48.4% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/2 · TLS	🥇 43,132 _{(151 MiB / 49.3% CPU)}	43,132 _{(151 MiB / 49.3% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/3 · QUIC	🥇 28,615 _{(153 MiB / 52% CPU)}	28,615 _{(153 MiB / 52% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/1 · plain	🥇 59,946 _{(231 MiB / 50.5% CPU)}	59,946 _{(231 MiB / 50.5% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/2 · plain	🥇 105,099 _{(107 MiB / 39.5% CPU)}	105,099 _{(107 MiB / 39.5% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/2 · TLS	🥇 81,941 _{(111 MiB / 38% CPU)}	81,941 _{(111 MiB / 38% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · plain	HTTP/3 · QUIC	🥇 34,410 _{(228 MiB / 49% CPU)}	34,410 _{(228 MiB / 49% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/1 · plain	🥇 55,620 _{(228 MiB / 49.5% CPU)}	55,620 _{(228 MiB / 49.5% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/2 · plain	🥇 96,923 _{(114 MiB / 38% CPU)}	96,923 _{(114 MiB / 38% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/3 · QUIC	🥇 32,204 _{(233 MiB / 49.3% CPU)}	32,204 _{(233 MiB / 49.3% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/1 · plain	🥇 31,313 _{(319 MiB / 48.1% CPU)}	31,313 _{(319 MiB / 48.1% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/2 · TLS	🥇 30,142 _{(283 MiB / 48.4% CPU)}	30,142 _{(283 MiB / 48.4% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/3 · QUIC	🥇 23,327 _{(286 MiB / 45.9% CPU)}	23,327 _{(286 MiB / 45.9% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · plain (CONNECT)	HTTP/1 · TLS	🥇 37,282 _{(131 MiB / 47.8% CPU)}	37,282 _{(131 MiB / 47.8% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/1 · TLS	HTTP/1 · TLS	🥇 39,263 _{(109 MiB / 46.1% CPU)}	39,263 _{(109 MiB / 46.1% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/2 · TLS	🥇 76,804 _{(119 MiB / 36.8% CPU)}	76,804 _{(119 MiB / 36.8% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/2 · TLS	HTTP/1 · TLS	🥇 43,868 _{(220 MiB / 46.8% CPU)}	43,868 _{(220 MiB / 46.8% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)
MITM	HTTP/3 · QUIC	HTTP/1 · TLS	🥇 26,330 _{(294 MiB / 45.7% CPU)}	26,330 _{(294 MiB / 45.7% CPU)}	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)	Not possible (no MITM)

On this GHA shape, TWP H1 plain ÷ nginx H1 plain ≈ 0.83 (46,284 / 55,862). H1 TLS terminate ≈ 0.85 (36,518 / 43,011). TWP÷YARP H1 plain ≈ 1.12× (46,284 / 41,203). Bridges @ f9769503: H3→H1 ≈ 1.07× RPS / 0.80× Memory; H3→H2 ≈ 1.06× / 0.75×; H2 TLS→H1 ≈ 1.10× / 0.98×; H1→H2 ≈ 1.03× / 1.08× Memory. Absolute RPS swings by VM; prefer the ratio and median across repeats. MITM publishes the same 15 Client×Origin pairs as Reverse (inspectable/decrypt), then dual-crypto extras (CONNECT, TLS↔TLS). nginx/YARP cannot MITM.

nginx HTTP/3: inbound QUIC terminate → cleartext H1 (nginx-reverse-http3-cleartext) @ f9769503 bridges: sustain 0 (p99/error SLO miss) / peak 18,730. TWP/YARP H3→H1 on this row are from the same bridges pass. nginx still cannot speak HTTP/3 to an origin (no H3 upstream in this conf).

YARP HTTP/3 (this matrix): TWP leads H3→H1 ≈ 1.07× (23,227 / 21,638), H3→H2 ≈ 1.06× (25,529 / 24,112). H1→H2 ≈ 1.03× (28,343 / 27,456). H1→H3 ≈ 1.08× (21,375 / 19,843). h2c→H3 ≈ 1.03×.

Windows vs Linux: both CI envs are 4 vCPU / 16 GiB, but do not compare absolute RPS across OS. Linux nginx leads H1 plain/TLS terminate (TWP second, ahead of YARP). Windows bridges @ f9769503 H3→H1 leads YARP on RPS (1.02×) and Memory (0.69×). Cool laptop notes remain on Performance Local Lab.

Tiny JSON reverse is nginx’s best case on Linux

The tables above use ~64 B keep-alive GET on loopback. On Linux H1 reverse, nginx leads; YARP sits near TWP. Heavier bodies, POSTs, TLS handshake cost, and lossy/HOL workloads (below) change the picture. MITM rows remain TWP-only. nginx HTTP/3 is inbound-terminate only (see note above).

Why isn’t HTTP/3 > HTTP/2 > HTTP/1 in raw RPS?

For tiny JSON responses (~64 B) on loopback, that ordering is not expected: topology (TLS hop count, terminate vs MITM) dominates; HTTP/2 and HTTP/3 help multiplexing, not single-origin tiny-GET RPS. See the lossy tables below for a workload where protocol design matters.

Heavier reverse workloads

Separate from the tiny-GET matrix. Same measurement environments. Modes: compare-bodies, compare-post, compare-lossy, compare-tls-cost, compare-arch in RpsLoadProbe. PUT with the same body is the same proxy work as POST; DELETE with no body matches GET — only POST is published. Bodies/POST/lossy stay half-duplex. compare-arch is the slow-consumer / early-response / duplex set. Laptop numbers are on Performance Local Lab; CI medians go in the tables below.

Lossy link = userspace shim (not kernel netem): TCP gets per-buffer delay + occasional whole-connection stalls (honest HOL for multiplexed H2); UDP gets per-datagram delay + drops (QUIC). compare-lossy publishes H1/H2/H3; H3 is where the protocol design is supposed to matter.

Windows — heavier reverse GET (64 KiB / 256 KiB)

Median of 3 repeats on windows-latest @ 1f2d0eee. Source: Actions 32688081527 (compare-bodies). Warmup 2s / measure 8s. RPS cells include (MiB / CPU%) footprints.

Body	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
64 KiB	HTTP/1 · TLS	HTTP/1 · plain	🥇 8,600 _{(98 MiB / 50.1% CPU)}	8,600 _{(98 MiB / 50.1% CPU)}	906 _{(137 MiB / 24.9% CPU)}	906 _{(137 MiB / 24.9% CPU)}	6,903 _{(113 MiB / 45.6% CPU)}	6,903 _{(113 MiB / 45.6% CPU)}
64 KiB	HTTP/2 · TLS	HTTP/1 · plain	🥇 8,011 _{(186 MiB / 45.6% CPU)}	8,011 _{(186 MiB / 45.6% CPU)}	779 _{(138 MiB / 25% CPU)}	779 _{(138 MiB / 25% CPU)}	5,789 _{(136 MiB / 49.5% CPU)}	5,789 _{(136 MiB / 49.5% CPU)}
64 KiB	HTTP/3 · QUIC	HTTP/1 · plain	🥇 4,127 _{(128 MiB / 40.9% CPU)}	4,127 _{(128 MiB / 40.9% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	3,709 _{(189 MiB / 50.8% CPU)}	3,709 _{(189 MiB / 50.8% CPU)}
256 KiB	HTTP/1 · TLS	HTTP/1 · plain	🥇 2,824 _{(102 MiB / 48.7% CPU)}	2,824 _{(102 MiB / 48.7% CPU)}	249 _{(137 MiB / 24.9% CPU)}	249 _{(137 MiB / 24.9% CPU)}	1,884 _{(140 MiB / 48.5% CPU)}	1,884 _{(140 MiB / 48.5% CPU)}
256 KiB	HTTP/2 · TLS	HTTP/1 · plain	🥇 2,504 _{(154 MiB / 40.4% CPU)}	2,504 _{(154 MiB / 40.4% CPU)}	170 _{(139 MiB / 24.9% CPU)}	170 _{(139 MiB / 24.9% CPU)}	1,958 _{(101 MiB / 42.7% CPU)}	1,958 _{(101 MiB / 42.7% CPU)}
256 KiB	HTTP/3 · QUIC	HTTP/1 · plain	🥇 1,108 _{(129 MiB / 41.5% CPU)}	1,108 _{(129 MiB / 41.5% CPU)}	Not possible (no QUIC)	Not possible (no QUIC)	1,048 _{(176 MiB / 45.3% CPU)}	1,048 _{(176 MiB / 45.3% CPU)}

nginx/Windows collapses on large reverse bodies in this harness; treat as same-OS only. H1 TLS 64 KiB ≈ 1.25× YARP; 256 KiB ≈ 1.50×. H2→H1 64 KiB ≈ 1.38×; H3→H1 64 KiB ≈ 1.11×.

Linux — heavier reverse GET (64 KiB / 256 KiB)

Median of 3 repeats @ 1f2d0eee. Source: Actions 32688081527 (compare-bodies). Warmup 2s / measure 8s.

Body	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
64 KiB	HTTP/1 · TLS	HTTP/1 · plain	12,030 _{(185 MiB / 42.3% CPU)}	12,030 _{(185 MiB / 42.3% CPU)}	🥇 13,402 _{(98 MiB / 37.3% CPU)}	13,402 _{(98 MiB / 37.3% CPU)}	9,932 _{(169 MiB / 47.9% CPU)}	9,932 _{(169 MiB / 47.9% CPU)}
64 KiB	HTTP/2 · TLS	HTTP/1 · plain	🥇 8,850 _{(247 MiB / 39.5% CPU)}	8,850 _{(247 MiB / 39.5% CPU)}	6,886 _{(105 MiB / 24.3% CPU)}	6,886 _{(105 MiB / 24.3% CPU)}	7,294 _{(164 MiB / 47.7% CPU)}	7,294 _{(164 MiB / 47.7% CPU)}
64 KiB	HTTP/3 · QUIC	HTTP/1 · plain	🥇 7,504 _{(230 MiB / 42.9% CPU)}	7,504 _{(230 MiB / 42.9% CPU)}	2,417 _{(116 MiB / 17.5% CPU)}	2,417 _{(116 MiB / 17.5% CPU)}	5,191 _{(242 MiB / 52.6% CPU)}	5,191 _{(242 MiB / 52.6% CPU)}
256 KiB	HTTP/1 · TLS	HTTP/1 · plain	🥇 3,868 _{(124 MiB / 31.6% CPU)}	3,868 _{(124 MiB / 31.6% CPU)}	3,850 _{(99 MiB / 29% CPU)}	3,850 _{(99 MiB / 29% CPU)}	2,912 _{(175 MiB / 43.5% CPU)}	2,912 _{(175 MiB / 43.5% CPU)}
256 KiB	HTTP/2 · TLS	HTTP/1 · plain	🥇 2,249 _{(207 MiB / 31.8% CPU)}	2,249 _{(207 MiB / 31.8% CPU)}	1,804 _{(111 MiB / 23.3% CPU)}	1,804 _{(111 MiB / 23.3% CPU)}	1,919 _{(167 MiB / 44.9% CPU)}	1,919 _{(167 MiB / 44.9% CPU)}
256 KiB	HTTP/3 · QUIC	HTTP/1 · plain	🥇 1,864 _{(177 MiB / 41.9% CPU)}	1,864 _{(177 MiB / 41.9% CPU)}	642 _{(102 MiB / 18.2% CPU)}	642 _{(102 MiB / 18.2% CPU)}	1,533 _{(191 MiB / 49.8% CPU)}	1,533 _{(191 MiB / 49.8% CPU)}

On this GHA pass TWP÷YARP H1 TLS ≈ 1.21× (64 KiB) / 1.33× (256 KiB); H2→H1 ≈ 1.21× / 1.17×; H3→H1 ≈ 1.45× / 1.22×. TWP÷nginx H1 TLS ≈ 0.90 / 1.00. Absolute RPS swings by VM; prefer ratios.

Windows — POST 64 KiB request + 64 KiB response

Median of 3 repeats on windows-latest @ d3566486. Source: Actions 32711461804 (compare-post). H1 keep-alive POST hang fixed (session-lite + reusable guard).

Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
HTTP/1 · TLS	HTTP/1 · plain	🥇 6,720 _{(92 MiB / 44% CPU)}	6,720 _{(92 MiB / 44% CPU)}	353 _{(137 MiB / 24.6% CPU)}	353 _{(137 MiB / 24.6% CPU)}	4,767 _{(113 MiB / 56.2% CPU)}	4,767 _{(113 MiB / 56.2% CPU)}
HTTP/2 · TLS	HTTP/1 · plain	🥇 4,576 _{(183 MiB / 48.3% CPU)}	4,576 _{(183 MiB / 48.3% CPU)}	337 _{(137 MiB / 24.6% CPU)}	337 _{(137 MiB / 24.6% CPU)}	4,018 _{(117 MiB / 52.4% CPU)}	4,018 _{(117 MiB / 52.4% CPU)}
HTTP/3 · QUIC	HTTP/1 · plain	🥇 2,346 _{(158 MiB / 41.3% CPU)}	2,346 _{(158 MiB / 41.3% CPU)}	Not possible	Not possible	2,133 _{(156 MiB / 47.4% CPU)}	2,133 _{(156 MiB / 47.4% CPU)}

TWP leads H1 POST (1.41× YARP), H2 POST (1.14× YARP), and H3 POST (~1.10× YARP).

Linux — POST 64 KiB request + 64 KiB response

Median of 3 repeats @ d3566486. Source: Actions 32711461804 (compare-post).

Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
HTTP/1 · TLS	HTTP/1 · plain	🥇 4,674 _{(125 MiB / 44.9% CPU)}	4,674 _{(125 MiB / 44.9% CPU)}	4,029 _{(96 MiB / 48.9% CPU)}	4,029 _{(96 MiB / 48.9% CPU)}	3,104 _{(178 MiB / 55.2% CPU)}	3,104 _{(178 MiB / 55.2% CPU)}
HTTP/2 · TLS	HTTP/1 · plain	🥇 3,102 _{(230 MiB / 49.1% CPU)}	3,102 _{(230 MiB / 49.1% CPU)}	1,963 _{(99 MiB / 22.3% CPU)}	1,963 _{(99 MiB / 22.3% CPU)}	2,489 _{(148 MiB / 47.9% CPU)}	2,489 _{(148 MiB / 47.9% CPU)}
HTTP/3 · QUIC	HTTP/1 · plain	🥇 2,903 _{(227 MiB / 43.5% CPU)}	2,903 _{(227 MiB / 43.5% CPU)}	750 _{(106 MiB / 24.1% CPU)}	750 _{(106 MiB / 24.1% CPU)}	2,555 _{(253 MiB / 50% CPU)}	2,555 _{(253 MiB / 50% CPU)}

Linux nginx H1/H2/H3 POST completed (nginx.org mainline). TWP÷YARP H1 ≈ 1.51×; H2 ≈ 1.25×; H3 ≈ 1.14×. TWP÷nginx H3 ≈ 3.87×.

Windows — lossy / high-RTT (H2 HOL / H3 loss)

Userspace 5 ms one-way delay + 1% TCP connection stall (H1/H2) or UDP datagram drop (H3); 64 KiB GET. H1/H2: median of 3 repeats on windows-latest @ 1f2d0eee — 32688085411 (compare-lossy). H3: GHA Windows userspace UDP shim collapses (sustain 0); published H3 row is the laptop quic-http3 remasure under the same delay/loss workload (Performance Local Lab, windows-20260822-lossy-h3-quic/).

Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
HTTP/1 · TLS	HTTP/1 · plain	663 _{(107 MiB / 5.4% CPU)}	663 _{(107 MiB / 5.4% CPU)}	645 _{(137 MiB / 18.3% CPU)}	645 _{(137 MiB / 18.3% CPU)}	🥇 663 _{(122 MiB / 5.1% CPU)}	663 _{(122 MiB / 5.1% CPU)}
HTTP/2 · TLS	HTTP/1 · plain	🥇 86 _{(126 MiB / 1.9% CPU)}	86 _{(126 MiB / 1.9% CPU)}	18 _{(138 MiB / 1.1% CPU)}	18 _{(138 MiB / 1.1% CPU)}	18 _{(98 MiB / 1.7% CPU)}	18 _{(98 MiB / 1.7% CPU)}
HTTP/3 · QUIC	HTTP/1 · plain	🥇 1,572	1,572	Not possible (no QUIC)	Not possible	0	50

TWP H2 HOL leads (4.8× YARP). H3 is the protocol-shape win vs H2 HOL on the same lossy session (112× H2); YARP H3 did not hold the p99 SLO under this userspace UDP shim (sustain 0, peak 50).

Linux — lossy / high-RTT (H2 HOL / H3 loss)

Median of 3 repeats @ 1f2d0eee. Source: 32688085411 (compare-lossy; lossy H3 uses quic-http3).

Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
HTTP/1 · TLS	HTTP/1 · plain	🥇 1,204 _{(140 MiB / 13.1% CPU)}	1,204 _{(140 MiB / 13.1% CPU)}	1,209 _{(96 MiB / 6.8% CPU)}	1,209 _{(96 MiB / 6.8% CPU)}	1,199 _{(152 MiB / 16.3% CPU)}	1,199 _{(152 MiB / 16.3% CPU)}
HTTP/2 · TLS	HTTP/1 · plain	🥇 314 _{(192 MiB / 6.6% CPU)}	314 _{(192 MiB / 6.6% CPU)}	40 _{(99 MiB / 0.4% CPU)}	40 _{(99 MiB / 0.4% CPU)}	44 _{(119 MiB / 1.6% CPU)}	44 _{(119 MiB / 1.6% CPU)}
HTTP/3 · QUIC	HTTP/1 · plain	328 _{(147 MiB / 12.2% CPU)}	328 _{(147 MiB / 12.2% CPU)}	86 _{(107 MiB / 2.2% CPU)}	86 _{(107 MiB / 2.2% CPU)}	🥇 332 _{(185 MiB / 20.7% CPU)}	332 _{(185 MiB / 20.7% CPU)}

TWP H2 HOL ≫ YARP (~7.1×). H3 TWP÷YARP ≈ 0.99×.

Architecture-sensitive

compare-arch isolates slow app readers, origin-early response, H2 duplex, and WebSocket echo. See TWP vs YARP IO model. Laptop 1-rep numbers are on Performance Local Lab.

Median of 3 repeats on matched 4 vCPU / 16 GiB runners @ d3566486 (32711464527) (compare-arch). Slow consumer = 256 KiB GET, 16 KiB read + 8 ms sleep. Early response = 64 KiB POST, origin writes after 8 KiB. Duplex H2 = overlapping 64 KiB POST on H2 TLS↔H2 TLS. WebSocket = echo round-trips/sec. H1 early-response unblocked by session-lite keep-alive POST fix.

compare-lossy (slow network) is already published above; it is not a slow app reader.

Windows

Scenario	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Slow consumer (256 KiB GET, throttled client read)	HTTP/1 · TLS	HTTP/1 · plain	🥇 248 _{(93 MiB / 4.4% CPU)}	248 _{(93 MiB / 4.4% CPU)}	194 _{(141 MiB / 24.5% CPU)}	194 _{(141 MiB / 24.5% CPU)}	244 _{(107 MiB / 5% CPU)}	244 _{(107 MiB / 5% CPU)}
Slow consumer (256 KiB GET, throttled client read)	HTTP/2 · TLS	HTTP/1 · plain	248 _{(118 MiB / 5% CPU)}	248 _{(118 MiB / 5% CPU)}	169 _{(141 MiB / 24.8% CPU)}	169 _{(141 MiB / 24.8% CPU)}	🥇 256 _{(109 MiB / 6.9% CPU)}	256 _{(109 MiB / 6.9% CPU)}
Slow consumer (256 KiB GET, throttled client read)	HTTP/3 · QUIC	HTTP/1 · plain	🥇 268 _{(98 MiB / 19.1% CPU)}	268 _{(98 MiB / 19.1% CPU)}	Not possible (no QUIC)	Not possible	259 _{(161 MiB / 22.4% CPU)}	259 _{(161 MiB / 22.4% CPU)}
Early response (origin writes after first request chunk)	HTTP/1 · TLS	HTTP/1 · plain	🥇 5,034 _{(85 MiB / 38% CPU)}	5,034 _{(85 MiB / 38% CPU)}	349 _{(136 MiB / 24.6% CPU)}	349 _{(136 MiB / 24.6% CPU)}	3,441 _{(114 MiB / 41.6% CPU)}	3,441 _{(114 MiB / 41.6% CPU)}
Early response (origin writes after first request chunk)	HTTP/2 · TLS	HTTP/1 · plain	🥇 4,285 _{(143 MiB / 43.3% CPU)}	4,285 _{(143 MiB / 43.3% CPU)}	300 _{(137 MiB / 24.5% CPU)}	300 _{(137 MiB / 24.5% CPU)}	3,016 _{(109 MiB / 39.9% CPU)}	3,016 _{(109 MiB / 39.9% CPU)}
Early response (origin writes after first request chunk)	HTTP/3 · QUIC	HTTP/1 · plain	🥇 2,263 _{(136 MiB / 43.5% CPU)}	2,263 _{(136 MiB / 43.5% CPU)}	Not possible (no QUIC)	Not possible	1,985 _{(155 MiB / 53.6% CPU)}	1,985 _{(155 MiB / 53.6% CPU)}
Duplex (both directions live)	HTTP/2 · TLS	HTTP/2 · TLS	885 _{(113 MiB / 13.1% CPU)}	885 _{(113 MiB / 13.1% CPU)}	Not possible	Not possible	🥇 2,293 _{(119 MiB / 38.5% CPU)}	2,293 _{(119 MiB / 38.5% CPU)}
Duplex (WebSocket / extended CONNECT)	HTTP/1 · TLS	HTTP/1 · plain	🥇 31,149 _{(93 MiB / 44.8% CPU)}	31,149 _{(93 MiB / 44.8% CPU)}	18,388 _{(137 MiB / 24.7% CPU)}	18,388 _{(137 MiB / 24.7% CPU)}	28,676 _{(89 MiB / 44.6% CPU)}	28,676 _{(89 MiB / 44.6% CPU)}

Linux

Scenario	Client	Origin	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Slow consumer (256 KiB GET, throttled client read)	HTTP/1 · TLS	HTTP/1 · plain	464 _{(116 MiB / 9.7% CPU)}	464 _{(116 MiB / 9.7% CPU)}	🥇 473 _{(98 MiB / 6.6% CPU)}	473 _{(98 MiB / 6.6% CPU)}	419 _{(147 MiB / 15.3% CPU)}	419 _{(147 MiB / 15.3% CPU)}
Slow consumer (256 KiB GET, throttled client read)	HTTP/2 · TLS	HTTP/1 · plain	468 _{(140 MiB / 19.1% CPU)}	468 _{(140 MiB / 19.1% CPU)}	🥇 477 _{(108 MiB / 13.7% CPU)}	477 _{(108 MiB / 13.7% CPU)}	472 _{(144 MiB / 25% CPU)}	472 _{(144 MiB / 25% CPU)}
Slow consumer (256 KiB GET, throttled client read)	HTTP/3 · QUIC	HTTP/1 · plain	🥇 472 _{(133 MiB / 36.3% CPU)}	472 _{(133 MiB / 36.3% CPU)}	410 _{(122 MiB / 24.4% CPU)}	410 _{(122 MiB / 24.4% CPU)}	469 _{(197 MiB / 41% CPU)}	469 _{(197 MiB / 41% CPU)}
Early response (origin writes after first request chunk)	HTTP/1 · TLS	HTTP/1 · plain	🥇 4,637 _{(132 MiB / 47.7% CPU)}	4,637 _{(132 MiB / 47.7% CPU)}	3,998 _{(95 MiB / 50.6% CPU)}	3,998 _{(95 MiB / 50.6% CPU)}	3,088 _{(173 MiB / 56.8% CPU)}	3,088 _{(173 MiB / 56.8% CPU)}
Early response (origin writes after first request chunk)	HTTP/2 · TLS	HTTP/1 · plain	🥇 3,132 _{(230 MiB / 46.4% CPU)}	3,132 _{(230 MiB / 46.4% CPU)}	1,925 _{(99 MiB / 22.4% CPU)}	1,925 _{(99 MiB / 22.4% CPU)}	2,273 _{(132 MiB / 48.3% CPU)}	2,273 _{(132 MiB / 48.3% CPU)}
Early response (origin writes after first request chunk)	HTTP/3 · QUIC	HTTP/1 · plain	🥇 2,875 _{(220 MiB / 45.9% CPU)}	2,875 _{(220 MiB / 45.9% CPU)}	708 _{(107 MiB / 24% CPU)}	708 _{(107 MiB / 24% CPU)}	2,042 _{(248 MiB / 48.7% CPU)}	2,042 _{(248 MiB / 48.7% CPU)}
Duplex (both directions live)	HTTP/2 · TLS	HTTP/2 · TLS	378 _{(136 MiB / 9.2% CPU)}	378 _{(136 MiB / 9.2% CPU)}	Not possible	Not possible	🥇 1,706 _{(149 MiB / 45.4% CPU)}	1,706 _{(149 MiB / 45.4% CPU)}
Duplex (WebSocket / extended CONNECT)	HTTP/1 · TLS	HTTP/1 · plain	31,574 _{(122 MiB / 43.7% CPU)}	31,574 _{(122 MiB / 43.7% CPU)}	🥇 32,771 _{(96 MiB / 35.6% CPU)}	32,771 _{(96 MiB / 35.6% CPU)}	26,797 _{(122 MiB / 44.5% CPU)}	26,797 _{(122 MiB / 44.5% CPU)}

Slow consumer is sleep-bound; H1/H2/H3 sit in the same band. Early-response H1/H2/H3: TWP leads (H1 early ≈ 1.46× / 1.50× YARP Win/Linux after keep-alive POST fix). Duplex H2: YARP leads by design — Win ≈ 0.39× (885 / 2,293), Linux ≈ 0.22× (378 / 1,706); irreducible concurrent-copier cell (see IO model). WebSocket: TWP leads Windows ≈ 1.09× YARP; Linux nginx leads.

TLS termination cost (H1 TLS → cleartext origin)

Isolates keep-alive tiny GET vs new connection per request (handshake-dominated) vs keep-alive 256 KiB. Product comparison uses RPS and end-to-end latency; TWP can also capture ClientTlsTiming when TWP_RPS_CAPTURE_TLS=1 (child process) — nginx/YARP have no equivalent hook.

Windows

Median of 3 repeats on windows-latest @ 1f2d0eee. Source: Actions 32688087733 (compare-tls-cost). Absolute RPS on GHA swings hard; prefer TWP÷YARP.

Workload	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Keep-alive · tiny GET	🥇 25,426 _{(81 MiB / 50.7% CPU)}	25,426 _{(81 MiB / 50.7% CPU)}	12,864 _{(137 MiB / 24.8% CPU)}	12,864 _{(137 MiB / 24.8% CPU)}	23,364 _{(107 MiB / 50.4% CPU)}	23,364 _{(107 MiB / 50.4% CPU)}
New-connection · tiny GET	🥇 769 _{(86 MiB / 10% CPU)}	769 _{(86 MiB / 10% CPU)}	256 _{(136 MiB / 24.6% CPU)}	256 _{(136 MiB / 24.6% CPU)}	753 _{(114 MiB / 9.9% CPU)}	753 _{(114 MiB / 9.9% CPU)}
Keep-alive · 256 KiB GET	🥇 2,886 _{(116 MiB / 44.5% CPU)}	2,886 _{(116 MiB / 44.5% CPU)}	259 _{(136 MiB / 25% CPU)}	259 _{(136 MiB / 25% CPU)}	2,512 _{(137 MiB / 45.6% CPU)}	2,512 _{(137 MiB / 45.6% CPU)}

Linux

Median of 3 repeats @ 1f2d0eee. Source: Actions 32688087733 (compare-tls-cost).

Workload	TWP sustain	TWP peak	nginx sustain	nginx peak	YARP sustain	YARP peak
Keep-alive · tiny GET	51,331 _{(96 MiB / 49% CPU)}	51,331 _{(96 MiB / 49% CPU)}	🥇 66,322 _{(99 MiB / 39.8% CPU)}	66,322 _{(99 MiB / 39.8% CPU)}	45,016 _{(136 MiB / 49.7% CPU)}	45,016 _{(136 MiB / 49.7% CPU)}
New-connection · tiny GET	1,666 _{(125 MiB / 39% CPU)}	1,666 _{(125 MiB / 39% CPU)}	🥇 1,729 _{(101 MiB / 34.6% CPU)}	1,729 _{(101 MiB / 34.6% CPU)}	1,652 _{(152 MiB / 38.4% CPU)}	1,652 _{(152 MiB / 38.4% CPU)}
Keep-alive · 256 KiB GET	5,208 _{(122 MiB / 29.8% CPU)}	5,208 _{(122 MiB / 29.8% CPU)}	🥇 5,272 _{(100 MiB / 27% CPU)}	5,272 _{(100 MiB / 27% CPU)}	4,130 _{(175 MiB / 42.4% CPU)}	4,130 _{(175 MiB / 42.4% CPU)}

All three workloads are >1.00× YARP on both OS. nginx leads Linux keep-alive tiny and Linux new-connection; TWP is second, YARP third.

Other measurements

What	Result
HTTPS TTFB vs direct (median, 14 hosts)	Cold ≈ parity (−1 ms); warm −25 ms (proxy faster)
HTTP/1 loopback GET (no body intercept)	~186 µs, ~17.5 KB allocated / request
Basic example footprint (Release, after load)	~74 MB working set · ~24–29 MB private bytes

dotnet run -c Release --project benchmarks/Titanium.Web.Proxy.Benchmarks -- --filter '*Throughput*'

Benchmark	Setup	Mean	Allocated / op
HTTP/1 GET through proxy	Passthrough	186 µs	17.5 KB
HTTP/2 multiplexed GETs	10 concurrent streams	3.0 ms / batch	~14 KB / request

Raising limits on large hosts

There is no artificial upper clamp on server defaults. Per-endpoint overrides:

Knob	Scope	Default	Override
`ProxyServer.MaxCachedConnections`	process, per upstream host	128	any ≥ 1
`ProxyEndPoint.MaxCachedConnections`	endpoint → pool depth for that EP’s sessions	null (use server)	e.g. `256` on reverse EP
`ProxyEndPoint.MaxConcurrentClients`	endpoint admission	null (off)	any ≥ 1
`ResourceLimits.MaxConcurrentStreamsPerConnection`	H2 streams	256	`ProxyResourceLimits.Create(...)`
`TransparentQuicProxyEndPoint.MaxInboundBidirectionalStreams`	H3	100 (probe uses 256)	property on EP
`ForwardCleartext`	transparent TLS terminate	false	`true` + decrypt

proxy.MaxCachedConnections = 512;
proxy.ResourceLimits = ProxyResourceLimits.Create(
    /* … */,
    maxConcurrentStreamsPerConnection: 1000,
    maxCachedConnectionsPerHost: 512,
    /* … */);

var ep = new TransparentProxyEndPoint(IPAddress.Any, 443, decryptSsl: true)
{
    ForwardHost = "127.0.0.1",
    ForwardPort = 8080,
    ForwardCleartext = true,
    MaxCachedConnections = 256,
    GenericCertificateName = "example.com"
};
ep.BeforeSslAuthenticate += (_, a) =>
{
    a.UpstreamHttpProtocol = UpstreamHttpProtocol.Http11;
    a.AllowHttpProtocolTranslation = true; // HTTP/2 client → HTTP/1 origin
    return Task.CompletedTask;
};

Performance

Performance

Contents

Measurement environment

Windows (GitHub-hosted windows-latest)

Linux (GitHub-hosted ubuntu-latest)

Saturation control

Block A — H1 plain

Block B — H2 TLS→H1

Block C — H3→H1

Windows — Titanium vs nginx vs YARP

Linux — Titanium vs nginx vs YARP

Tiny JSON reverse is nginx’s best case on Linux

Why isn’t HTTP/3 > HTTP/2 > HTTP/1 in raw RPS?

Heavier reverse workloads

Windows — heavier reverse GET (64 KiB / 256 KiB)

Linux — heavier reverse GET (64 KiB / 256 KiB)

Windows — POST 64 KiB request + 64 KiB response

Linux — POST 64 KiB request + 64 KiB response

Windows — lossy / high-RTT (H2 HOL / H3 loss)

Linux — lossy / high-RTT (H2 HOL / H3 loss)

Architecture-sensitive

Windows

Linux

TLS termination cost (H1 TLS → cleartext origin)

Windows

Linux

Other measurements

Raising limits on large hosts

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Uh oh!

Clone this wiki locally

Windows (GitHub-hosted `windows-latest`)

Linux (GitHub-hosted `ubuntu-latest`)