Meta — Engineering Performance
176 engineers now deliver what 485 would have in Q1 2025.
Performance snapshot
Today's rolling 90-day reading for Meta, compared with the start of the series. Pick a window to move that comparison point.
Avg. perf / dev / mo
+175.8%
0.71 → 1.96 ETV
Active engineers
−20.7%
222.0 → 176.0
Features
+0.2pp
31.3% → 31.5%
vs. 500 OSS index
0.51x
0.78x → 0.51x · −49% below
Engineering capacity
Effective engineers behind Meta, against its pre-AI baseline. Each subject has its own: Meta's is 0.71 ETV / dev / mo, its first reading in Q1 2025. Per-engineer ETV divided by that 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. Because each baseline is its own, every subject opens at 1.0x on its first day: multiples measure improvement and are not comparable between subjects.
Meta vs. 500 OSS Performance Index
Per-engineer ETV for Meta against the pooled 500 OSS Performance Index. 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. Latest reading: Meta is 49% below the index (1.96 vs 3.85 ETV/dev/mo). At the start of the tracked period the gap was 22% below.
Behind the numbers
Written summary of the work completed each month.
In August 2026, the team delivered significant build architecture refactoring, dependency upgrades, and developer tooling integrations across 665 commits. Overall output reached 112 points—up +110% compared to the 5-month average of 53 points—representing a genuine step up over the multi-month average and recent monthly run rates. Key deliveries centered on multi-tenant architecture preparation for Buck2, rule migrations to ASTGREPLINT, and AI code review tooling integration.
Highlights
- Introduced AI-driven code review workflows into CI via
@expo/code-review-cliand GitHub Actions in 4f95564c (Peter). - Added repository-aware guidance for AI agents via the new
buck2 docs agentcommand in cea8779a (Chenhao) with shared schema parsing across buck2_common and buck2_server in 098bd921 (Chenhao). - Architected Buck2 daemon state for multi-tenant repository support by isolating
RepoStatefromDaemonStateDataacross a6f65831 (Ben), fcb9ce92 (Ben), and 510a7db0 (Ben). - Optimized build rule generation overhead across Rust and C++ preludes by sharing toolchain compiler argsfiles and wrapper scripts (587485be (Jeremy), fa45a1ba (Jeremy), and d342af7c (Jeremy)).
- Resolved a memory leak in React DOM fragment
IntersectionObservertarget cleanup in 065bc84e (Jack).
Observations
- Total commit volume reached 665 commits, a +95% increase compared to the 340-commit 5-month average.
- Maintenance activity surged to a score of 37 (+141% compared to the 5-month average of 15), driven by major dependency updates across
annotate-snippets(ef5ff615 (David), 5620c2e0 (David), d8a941d0 (David)),lsp-server(e57b6be7 (David), f81ff125 (David)),object(01426d35 (David), 235192b4 (David)), and collections refactoring tobuck2_hashin 689bc239 (Ben). - Lint infrastructure saw active migration away from legacy PatternLint to ASTGREPLINT and Fixit across 0ece3275 (Ben), 8741524e (Ben), 4da390d6 (Ben), and 9fb631a6 (Ben).
- Fixes score increased to 21 (+176% compared to the 7-point 5-month average), encompassing critical concurrency fixes in
buck2_forkserverin f1511c94 (Jeremy) and CI test flake mitigations in a08b89a1 (Scott) and 26ebd7b8 (Scott).
Based on 665 commits91.4 ETVUpdated Sep 30, 2026, 4:01 PM
Repositories
Where each repository stands: average performance per engineer per month over the last 90 days, with the rolling 90-day curve behind it. The range picks the window (past 90d): it sets how much of the curve you see, the Δ across it, and the span the work mix is measured over. Ranked highest first.
pyrefly
Avg performance
6.47 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
+223.9%
Work mix
Features
31%
Maint
21%
Tests
20%
Docs
3%
Fixes
26%
buck2
Avg performance
1.82 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
+166.5%
Work mix
Features
34%
Maint
38%
Tests
12%
Docs
2%
Fixes
15%
fbthrift
Avg performance
1.35 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
-12.8%
Work mix
Features
34%
Maint
10%
Tests
44%
Docs
2%
Fixes
9%
fboss
Avg performance
1.11 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
+41.7%
Work mix
Features
32%
Maint
8%
Tests
37%
Docs
3%
Fixes
22%
docusaurus
Avg performance
0.93 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
-27.6%
Work mix
Features
14%
Maint
36%
Tests
31%
Docs
8%
Fixes
10%
folly
Avg performance
0.81 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
+419.2%
Work mix
Features
27%
Maint
13%
Tests
37%
Docs
10%
Fixes
14%
react-native
Avg performance
0.73 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
-2.0%
Work mix
Features
29%
Maint
22%
Tests
33%
Docs
5%
Fixes
12%
react
Avg performance
0.69 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
+35.6%
Work mix
Features
18%
Maint
11%
Tests
32%
Docs
1%
Fixes
38%
fresco
Avg performance
0.13 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
-31.8%
Work mix
Features
33%
Maint
12%
Tests
42%
Docs
3%
Fixes
10%
hermes
Avg performance
0.00 ETV
per engineer per month
Avg. dev performance / month (90-day MA)
-100.0%
Work mix
Features
0%
Maint
0%
Tests
0%
Docs
0%
Fixes
0%
Performance Composition
Each month's output split by type of work: Features (new value), Maintenance (sustaining systems), Tests, Docs, and Fixes (rework). The yellow line is output per engineer, so when it rises each engineer is delivering more, whatever the team size did. Unit: Engineering Throughput Value (ETV).
Cost per Performance Unit
−64%
If performance per engineer more than doubled, each unit of engineering performance now costs approximately 64% less than at the baseline 90-day window (ending 2025-04-01). Treat this as a direction, not a price: the exact figure depends on fully-loaded engineer cost, but which way it moved is not in doubt.
Effective Capacity Added
+309 engineers
At today's productivity, the current 176-person team delivers the performance equivalent of 485 engineers at the baseline 90-day rolling window (ending 2025-04-01). That's roughly 309 engineers worth of capacity added through productivity gains, not hiring.
CapEx vs OpEx
Each month's work split two ways. CapEx (capitalizable investment) is the work that builds the asset: Features, plus the Tests that prove it works and the Docs that explain it. OpEx (operating expense) is keeping it running: Maintenance and Fixes. The yellow line is the CapEx share, so a rising line means more of the month went into building new rather than sustaining what exists. Unit: Engineering Throughput Value (ETV).
Hours per Repository
Trailing 90-day window (64 working days). Org-level capacity is allocated to each repo by its share of org performance, then split CapEx / OpEx by that repo's own Features + Tests + Docs vs Maintenance + Fixes mix.
- CapEx %
- 80.5%
- OpEx %
- 19.5%
- CapEx %
- 76.9%
- OpEx %
- 23.1%
- CapEx %
- 73.3%
- OpEx %
- 26.7%
- CapEx %
- 70.4%
- OpEx %
- 29.6%
- CapEx %
- 65.8%
- OpEx %
- 34.2%
- CapEx %
- 53.4%
- OpEx %
- 46.6%
- CapEx %
- 53.4%
- OpEx %
- 46.6%
- CapEx %
- 51.5%
- OpEx %
- 48.5%
- CapEx %
- 47.3%
- OpEx %
- 52.7%
- CapEx %
- 0.0%
- OpEx %
- 0.0%
- CapEx %
- 60.2%
- OpEx %
- 39.8%
Feature Contribution
Who shipped each month's new feature work, as a share of that month's total. Bands of similar width mean new value is coming from across the team; one band that stays wide means most of it rests on the same person. Named engineers shipped the most Features over the period. Everyone else is grouped as Others.
Quarterly Summary
Engineers and the Features / Maintenance / Tests / Docs / Fixes mix for each quarter. Cost / Perf Unit is what one unit of performance costs against Q2'25. Engineers vs headcount is measured against this org's own pre-AI baseline instead, its first reading in the index, so it agrees with the capacity tile and chart above.
- Engineers
- 238
- Cost / Perf Unit
- 0%
- Engineers vs headcount
- +55 engineers
- Work mix
- 34% Features
- Engineers
- 245
- Cost / Perf Unit
- +2%
- Engineers vs headcount
- +51 engineers
- Work mix
- 34% Features
- Engineers
- 244
- Cost / Perf Unit
- +11%
- Engineers vs headcount
- +26 engineers
- Work mix
- 35% Features
- Engineers
- 243
- Cost / Perf Unit
- −21%
- Engineers vs headcount
- +134 engineers
- Work mix
- 34% Features
- Engineers
- 209
- Cost / Perf Unit
- −28%
- Engineers vs headcount
- +146 engineers
- Work mix
- 30% Features