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Solo builders: 8 sourced coding agent stories

One person working with agents, outside a company team. Of the 8 stories, 8 by the people who did the work. 2 involve an existing codebase and 6 started from scratch. Every number links to where it was published.

• Practitioner (own blog/paper) New product greenfield

  Token Clicker: a 33,716-line browser idle game shipped 19 hours after its specs with Claude Code

  Julien Renaux (independent developer) · 2026-09-28

  • 19 hours 39 minutes wall-clock (night included) Specs to launch
  • 33,716 lines TypeScript in src/
  • 1,758 unit, 34 pacing, 28 end-to-end Tests

  Claude Code

• Practitioner (own blog/paper) New product greenfield

  Solo developer builds a cross-platform tower defense game in about 30 days with Claude Code, for ~$2,755 in tokens

  Julien Renaux (independent developer) · 2026-09-10

  • ~30 days, ~12 working sessions Duration
  • 9,436 Tool calls
  • 17.7M Output tokens

  Claude Code

• Practitioner (own blog/paper) Language port greenfield

  Simon Willison ports an HTML5 parser from Python to JavaScript with Codex CLI in about 4.5 hours

  Simon Willison (independent developer) · 2025-12-15

  • ~4–4.5 hours Idea to finished library
  • 8 Prompts
  • 9,000 lines of JavaScript, 43 commits Output

  OpenAI Codex

• Practitioner (own blog/paper) New product greenfield

  Emil Stenström builds JustHTML, a pure-Python HTML5 parser passing all 9,200+ html5lib tests, with Copilot agent mode

  Emil Stenström (independent developer) · 2025-12-14

  • A couple of months of off-hours Time
  • ~3,000 lines (plus ~11,000 lines of tests) Implementation code
  • All 9,200+ html5lib-tests passing

  GitHub Copilot

• Practitioner (own blog/paper) Feature brownfield

  Mitchell Hashimoto ships a non-trivial Ghostty feature with Amp in 16 sessions for $15.98

  Ghostty (Mitchell Hashimoto) · 2025-10-11

  • 16 Agent sessions
  • $15.98 Token spend
  • ~8 hours, over 3 days from first to last commit Hands-on time (author's estimate)

  Amp

• Practitioner (own blog/paper) Upgrade / modernisation brownfield

  Claude Code ports a 25-year-old Linux tape driver from kernel 2.4 to 6.8 over two evenings

  Dmitry Brant (independent developer) · 2025-09-07

  • Two evenings Time
  • 2.4 → 6.8 Kernel version jump
  • Probably several weeks (would have meant learning 25-year-old kernel development) Author's by-hand estimate

  Claude Code

• Practitioner (own blog/paper) New product greenfield

  Solo developer ships a 20,000-line native macOS app, writing fewer than 1,000 lines by hand

  Indragie Karunaratne (independent developer) · 2025-07-01

  • ~20,000 lines Codebase size
  • <1,000 lines (author's estimate) Written by hand
  • 2,000 lines of Python, written by Claude in a few hours of iteration Release automation script

  Claude Code

• Practitioner (own blog/paper) New product greenfield

  Pieter Levels builds a browser flight sim with Cursor in ~3 hours; it hits $1M ARR in 17 days

  Pieter Levels (indie maker) · 2025-03-11

  • ~3 hours (author's estimate) Time to first playable version
  • $87,000 MRR (~$1M ARR) Revenue after 17 days
  • 320,000 Players after 17 days

  Cursor