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Google

zerocopy — Engineering Performance

2 engineers all time · Feb 2025 – Aug 2026 · built 2026-08-24 · GitHub

Performance snapshot

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

Eff. capacity added

−0.6engineers

2 devs deliver like 1 (0.7x pre-AI)

Avg. perf / dev / mo (ETV)

−59.4%

1.54 → 0.62

Active engineers

±0%

2.0 → 2.0

Features

−7.5pp

34.2% → 26.7%

zerocopy vs. Google

Per-engineer ETV for zerocopy against Google 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.

zerocopy
0.62ETV / dev / mo
1.76 (73.9%) past 90d
Google
2.03ETV / dev / mo
+0.63 (+45.0%) 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 zerocopy, 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
1engineer-equivalents
−1 engineers above real headcount
Real engineers
2engineers
active in the trailing 90 days
Capacity vs pre-AI
0.7x
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
87.9 %
Top 3
100.0 %
Top 5
100.0 %

Josh Liebow-Feeser owns 87.9 % of commits.

Reports

Written summary of the work completed each month.

No monthly reports available yet.

Most impactful commits

Top 10 by ETV in the all-time window.