Work I started myself, usually because I wanted the thing to exist. This is the deep end on purpose — full technical detail behind every card, and no attempt to keep it short.
Three instrument engines (SF2 soundfont, subtractive synth, chromatic WAV sampler) over a low-latency PCM feed loop, with a FluidSynth fallback on desktop and web.
Audio engine ported from Dart to Rust behind flutter_rust_bridge in three parts — FX chain, then instruments, then SF2 onto rustysynth — each cut over only after byte-exact parity.
Reorderable effects chain (Freeverb, delay, low-pass filter), looper, arpeggiator, and metronome with selectable timbre.
EN/ES/FR/pt-BR UI, RevenueCat freemium gate, signed-release CD to Google Play with R8 gated in CI.
23 agent skills shipped in two formats from the same SKILL.md files: a Claude Code plugin marketplace, or bunx skills into any of 75+ agents.
Agent SkillsClaude Codebunx skillsMarkdownMIT
Nine skills compose a feature-delivery pipeline from vague idea to merged PR; each stage consumes the prior artifact and refuses to run on thin context.
babysit-prs drives a PR through bot and human review on its own loop until it merges; implementation-review gates the commit with seven parallel checks.
code-craft covers 7 languages and 12 frameworks, seo runs deterministic LLM-first audits, wstg covers OWASP security testing.
Every skill versioned independently, manifests validated in CI, progressive disclosure throughout.
Records two or more USB microphones on one computer in sync. Each mic runs on its own crystal clock, so over a long take they drift apart and desync.
RustcpalrtrbhoundMIT
The first mic listed becomes the master clock; every other one is linear-resampled to its exact sample count, correcting rate mismatch and drift in one step.
cpal capture into lock-free rtrb ring buffers; one WAV per mic plus a mix, written with hound.
Zero-config CLI: bare invocation lists numbered devices, record 0,1 captures until Enter, with optional fixed duration, --normalize and per-mic --gain.
Prebuilt Windows zip on GitHub Releases, with the build-from-source path documented for macOS and Linux.
Pure-Rust fixed-income library — yield curve interpolation, parametric fitting and bond pricing — published to crates.io with zero third-party numerical crates.
RustPCHIPNelder-MeadSvenssoncrates.io
Five methods: piecewise linear, C² cubic spline via Thomas solver, Fritsch-Carlson PCHIP, Nelson-Siegel and Svensson, fitted by an in-tree Nelder-Mead optimizer.
Compounding and implied forward rates (continuous, periodic incl. Brazil-252, simple); duration, convexity and par yield off any interpolator.
Zero-dependency date toolkit: ISDA 2006 day counts, BUS/252 ANBIMA calendar, coupon-schedule generation.
unsafe_code = "forbid" crate-wide, post-fit sanity checks with deterministic spline fallback, SLSA Level 3 provenance per tagged release.
Serverless disposable email — 10-minute inboxes free, 60-minute with custom domains on pro. Go Lambdas on Terraform-managed AWS, web and mobile in one monorepo.
GoAWS LambdaTerraformAstroSvelte 5React Native
SES inbound, S3, DynamoDB with TTL auto-delete, API Gateway and Route53, all Terraform-managed in us-east-1.
Paid tiers add TOTP two-factor auth, API keys, forwarding, webhook config, vanity addresses, inbox sharing and read receipts.
Astro + Svelte 5 web on Vercel, React Native + Expo mobile at ~80% parity, shared TypeScript API client.
PT-BR/ES/FR localization routed through Vercel rewrites; PolyForm Noncommercial license with gitleaks scanning in CI.
The other half
Client work is written up separately
These exist because I wanted them to — no client, no brief, no deadline. Where
someone was paying for an outcome, the write-ups carry the diagnosis and the numbers
instead of the source.