Merge State Visualizer

Simon Willison's Blog / 3/23/2026

💬 OpinionDeveloper Stack & InfrastructureTools & Practical Usage

Key Points

  • The Merge State Visualizer is introduced as a practical tool to explore CRDT-based merge states, with an interactive UI built via Pyodide.
  • Bram Cohen's essay on a CRDT-driven future of version control is highlighted, demonstrated with 470 lines of Python.
  • The author fed the Python code to Claude for an explanation, then built an interactive UI to illustrate the algorithms in action.
  • The post, a Simon Willison beat dated 22 March 2026, links to related articles about CRDTs and version-control topics.
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22nd March 2026

Tool Merge State Visualizer — # CRDT Merge State Visualizer

Bram Cohen wrote about his coherent vision for the future of version control using CRDTs, illustrated by 470 lines of Python.

I fed that Python (minus comments) into Claude and asked for an explanation, then had it use Pyodide to build me an interactive UI for seeing how the algorithms work.

Posted 22nd March 2026 at 6:57 pm

This is a beat by Simon Willison, posted on 22nd March 2026.

vcs 2 pyodide 25 bram-cohen 3 crdt 8

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