How fast is Bitcoin Core shipping code — and where is the effort going?
Scope: Core (bitcoin/bitcoin, gui, secp256k1) and Ecosystem (guix.sigs, HWI, qa-assets).
Codebase Anatomy & Subsystem Focus
Explore codebase architecture, language composition, and where active development effort is landing.
Subsystem Effort (Current Snapshot)
Shows how the codebase is structured by functional area, based on source files.
Breaks down file count by programming language.
Measures the size of each functional area by lines of code.
Displays dominant programming languages by lines of code.
Historical line-of-code trends are mathematically scaled to match the current static codebase size (0.9M LOC).
Evolution of Functional Areas (Authored Commits)
Tracks how development focus shifts across subsystems over time.
Longitudinal Tech Evolution (Lines of Code 2009-2025)
Tracks the growth of different programming languages over time.
Engineering Efficiency: Historical Churn vs. Net Change
Tracks the ratio of code added/deleted against the net change in repository size. Highlighting weeks where net LOC went down but churn was high reveals periods of intense refactoring and high-quality engineering discipline.
How to Analyze this Data
The grey bars represent total activity volume (adds + deletes). Large bars show heavy code modifications.
The solid line shows system growth or shrinkage. Dips below zero paired with high churn indicate refactoring weeks.
Net-negative sprints prove developers simplify the system rather than accumulating technical debt.