Claude Code, Copilot, Codex and MCP, tested on real code with real numbers. Plus 80+ free developer tools that run in your browser.
Search 80+ free tools · most work offline after the first load
§ 01 — Why developers trust it
Most tools execute locally, so your code never leaves the tab. The few that need a server say so on the page.
Only aggregate page-view stats. No signup needed, and nothing you type into a tool is tracked.
Most tools keep working offline once loaded. Every tool is free, with no paywall.
§ 02 — Toolchain index
A taste of the kit. All 80+ tools are free and run in your browser.
§ 03 — Latest writing
AI Agents
A production-minded guide to scheduling recurring VS Code agent tasks without overlapping runs, unsafe permissions, unreliable catch-up behavior, or unreviewed code changes.
Performance
A practical guide to comparing Responses API requests, interpreting cache-miss reasons, and preventing small request changes from quietly increasing latency and cost.
JavaScript
A production implementation guide to OpenAI async tool calling, covering the Responses API contract, durable job registries, late-result delivery, failure recovery, wait tools, and compatibility limits.
Developer Tools
A current implementation guide to GitHub Copilot content exclusions, including CLI and app support, pattern syntax, policy scope, REST auditing, testing, and documented limitations.
§ 04 — Guided learning
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