Benchmarks

Altair is compared against Express (Node.js) and Fiber (Go) on identical PostgreSQL-backed CRUD endpoints, driven by k6 over real HTTP. The harness lives in the repository at examples/benchmark_k6 and can be re-run locally.

Every framework gets the same 200-connection database budget. A discarded k6 warm-up run first ramps each app to 1,000 virtual users and absorbs the cold-start spike, then the measured run holds 1,000 VUs for 60 seconds. PostgreSQL is pinned to 6 CPUs / 2 GB — enough headroom that throughput is framework-limited, so per-request cost is what is measured.

Results

Workload Framework req/s avg p95 p99 p99.9 max
Write POST /items Fiber 17,088 57.0 ms 94.3 ms 131.7 ms 171.5 ms 242.4 ms
Altair 13,167 75.4 ms 101.3 ms 117.8 ms 145.9 ms 201.5 ms
Express 7,273 133.8 ms 232.1 ms 302.8 ms 1,036.8 ms 2,067.8 ms
Read GET /items/:id Fiber 19,527 37.1 ms 71.7 ms 103.5 ms 149.9 ms 236.3 ms
Altair 14,687 64.3 ms 129.0 ms 180.4 ms 318.4 ms 479.6 ms
Express 7,700 127.3 ms 197.3 ms 267.3 ms 350.3 ms 965.8 ms

All six runs completed with zero failed requests.

What the numbers say

  • Altair is ~1.8–1.9x faster than Express on throughput in both workloads, with a far tighter tail: its write p99.9 (145.9 ms) is 7x lower than Express's and its write max (201.5 ms) is the best of all three.
  • Fiber (Go) leads raw throughput — the honest gap is 0.75–0.77x. Altair's write tail is nevertheless tighter than Fiber's at every percentile from p99 up.
  • Altair's read tail runs ~2x Fiber's (p99.9 318.4 / max 479.6 ms). The outliers land inside one Boehm stop-the-world pause per second on the plateaued heap; the next optimization target is read-side allocation (JSON response building dominates), and it is tracked as follow-up work.

Methodology

  • One k6 warm-up run per phase (ramp to 1,000 VUs + settle) precedes the measured constant-vus run, so the summaries describe sustained load only.
  • The pool budget is the same for every framework: 200 connections total, matching PostgreSQL's max_connections = 220 headroom (Express and Fiber split theirs across 8 workers; Altair uses one shared pool).
  • Latency statistics: avg, med, p(90), p(95), p(99), p(99.9), max.
  • Raw k6 summary exports are committed next to the harness in results/.

Where this came from

The numbers are maintained together with the benchmark harness: see examples/benchmark_k6/README.md for the full report — the tail-latency investigation, the per-second GC pause measurement and the allocation findings — and the repository's CHANGELOG.md for what changed between measurement passes.

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