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Cloudflare

workerd — Engineering Performance

63 engineers all time · Jan 2025 – Aug 2026 · built 2026-08-23 · GitHub

Performance snapshot

Today's rolling 90-day reading for workerd, compared with the start of the series. Pick a window to move that comparison point.

Eff. capacity added

−8.3engineers

23 devs deliver like 15 (0.6x pre-AI)

Avg. perf / dev / mo (ETV)

+8.2%

0.51 → 0.55

Active engineers

−37.8%

37.0 → 23.0

Features

+27.3pp

35.2% → 62.5%

workerd vs. Cloudflare

Per-engineer ETV for workerd against Cloudflare as a whole. Both lines are 90-day rolling averages scaled to a 30-day month, so they share one axis and can be read against each other at any point. Pick a window to zoom the chart to it.

workerd
0.55ETV / dev / mo
+0.02 (+3.8%) past 90d
Cloudflare
1.27ETV / dev / mo
+0.23 (+22.1%) past 90d

Performance over time

ETV stacked by Features / Maintenance / Tests / Docs / Fixes — 90-day moving average, normalized to ETV / month.

Engineering capacity

Effective engineers behind workerd, in pre-AI terms. Per-engineer ETV divided by the Q1 2025 baseline of 0.86 ETV / dev / mo gives a capacity multiple, and that multiple applied to the engineers active in the trailing 90 days turns it into engineer-equivalents. The line is the real headcount, so the gap between line and area is what the leverage is worth.

Effective engineers
15engineer-equivalents
−8 engineers above real headcount
Real engineers
23engineers
active in the trailing 90 days
Capacity vs pre-AI
0.6x
per engineer, vs 0.86 ETV / dev / mo

Knowledge concentration

How dependent is this repo on a small number of engineers? Higher top-1 share = higher key-person risk.

Top 1
16.4 %
Top 3
36.2 %
Top 5
48.3 %

James M Snell owns 16.4 % of commits.

Reports

Written summary of the work completed each month.

No monthly reports available yet.

Top engineers

Most impactful commits

Top 10 by ETV in the all-time window.