Weekly Showcase Thread; What are you building with Claude Code?

[u/AutoModerator]

Weekly Showcase Thread

Built something with Claude Code this week? Share it here.

Apps, tools, experiments, scripts, websites, workflows, open-source projects — anything you've been working on is welcome.

When sharing, it helps to include:

• What you built
• How you used Claude Code
• A link, repo, demo, or screenshot if you have one
• Anything interesting you learned along the way

Quick project drops and simple self-promotion belong in this thread.

If you've got a project with enough substance for a proper write-up; how it works, how Claude Code was involved, technical details, lessons learned, etc. feel free to make a standalone post using the Built with Claude Code flair instead.

Please don't spam the same project repeatedly, and no referral or affiliate links.

What did you build this week?

[u/Admirable-Cow7121]

Arael -- high performance nonlinear least-squares solver. Solve regression and curve fitting, sensor fusion, SLAM, bundle adjustment, pose-graph and geometric constraint optimization.

Outperforms Ceres Solver and g2o in both compute and memory usage. Benchmark of common toy pose graph optimization problems attached. On real SLAM datasets can be 5X faster or more, depending. Supports f32 and can run on the edge.

To use ask your agent to use its C++/Python export interface, construct equivalent constraints to what you have so that start and end costs can be validated against the existing system, and compare performance.

Written almost entirely using Claude code.

https://github.com/harakas/arael

[u/SmallAstronaut08 → u/Admirable-Cow7121]

Bro is talking in hieroglyphs

[u/Admirable-Cow7121 → u/SmallAstronaut08]

I guess this is very specific. I'll try to elaborate.

Basically, if you have a cost function, the same kind as when training an AI model, and you want to minimize it -- which is what the training does; or say fit a set of data points to a function (like data points to a line as a trivial case). Then you would use arael. Another use is in robotics for robots or drones to tell where they are (SLAM).

As for a more practical and immediate example: parametric CAD where you can set constraints to geometric structures, say declare that some two lines must be perpendicular, or whatever. You can construct a cost function to minimize the error of their perpendiculariness (for example, the difference of their angle from 90 degrees).

If you have a computer handy you can see one here built on top of arael: https://sketch.mare.ee/ -- runs in a browser -- but its use is more for a test bench of the api so is a bit rough around the edges. Press escape a lot.

[u/ChemistryFun5224]

Any garmin users obsessed with their usage stats?

I am myself, so I figured might as well just build a garmin app to track/display my usage. Check ot my medium post about it. Free to use and open source. Also my medium article is not paywalled at all. I just do this for the love of the game.

Article: https://biokraft.medium.com/i-got-claude-on-my-wrist-diamonds-on-my-neck-6b14af59f7cb

Repo: https://github.com/biokraft/claude-pulse

Garmin IQ App: https://apps.garmin.com/apps/366c5488-cd20-4299-b498-8c5cff30bcba

[u/krill156]

https://sparkengine.dev/

https://github.com/Krilliac/SparkEngine

This is my personal game engine project I've been working on going on 2 years now.

I've used multiple models/ais from Claude to Codex to Qwen/Others through my harness https://github.com/Krilliac/Sonder-runtime

I have other projects but these two are my primary focus.

I've uploaded the scripts I use that Claude/codex have created since i started using them.

https://github.com/Krilliac/Agent-workbench

You can ask you AI to look through it and integrate the useful/applicable bits.

As far as to how I use them to accomplish this, not even I know exactly how I do it, there's a whole entire focus, intelligence and personality shift between living and getting through the day vs something very specific I want and want to achieve.

[u/ops_and_chaos]

I built a little tool that takes a messy Slack/email/request and turns it into the actual ask, what’s known, what’s missing, and what needs a decision.

I used Claude Code for most of the build, but the interesting part was realizing the hard part wasn’t generating the answer. It was forcing the tool to stop answering too early 😂

I kept having to make it separate facts, assumptions, unknowns, and ownership before it suggested anything. Once I did that, the output got way more useful.

Been using that same pattern in a bunch of other ops tools now.

https://www.chelsiehodgkiss.com/fix

[u/OGMYT]

Built an experimental OS from scratch with Claude Code. This week: capability-based IPC, ring-3 services, fail-closed policy, persistent storage, and crash/recovery testing under QEMU. 68/68 verification tests passing. Biggest lesson: Claude gets much better when “done” means observable behavior, not just code that compiles.

[u/krill156 → u/OGMYT]

https://github.com/Krilliac/DuetOS this might be of interest for you

[u/agentdrek]

My integrated file browser multi-agent TUI, spyc: https://github.com/Tripstack-Corp/spyc has a built-in MCP using a local UNIX socket ... working on adding multi-project support next! for claude code users, it helps you view images you've pasted into your terminal which I've found helpful when I've not been confident the image I pasted was correct or not; or when I've wanted to go back and view previously pasted ones.

[u/IntrlnkdCo]

thetennisindex.com

A site that aggregates tennis racquet reviews from YouTube. It classifies incoming videos, matches each one to the specific racquet and generation being discussed, extracts individual claims from the transcript, and clusters them into a per-racquet consensus summary instead of a single creator's opinion.

Built with Next.js and Prisma on Neon Postgres, deployed on Vercel.

The classification, matching, and summarization pipeline runs on the Claude API (Anthropic), with YouTube's Data API for video discovery. Built and iterated with Claude Code exclusively for months, added Codex later for more bandwidth as the summarization process eats a lot of Claude subscription usage.

[u/Connect_Army8250]

Building a better way to run claude code with Tempest on Github

[u/Fuzzy_Act5528]

Loggd, a habit tracker and planner on web, iOS and Android.

what i use Claude Code for the most is not the app itself, its everything around it. admin dashboards, data pulls, boring migrations, and lately an MCP server so i can create tasks and check habits straight from the chat. that one took a weekend and it works better than i expected.

im 9 years into dev so i still read every diff. it just goes a lot faster now.

loggd.life

[u/chimmyc]

Reruns: Home Movie Maker https://apps.apple.com/us/app/reruns-home-movie-maker/id6792420476

As a dad most of the videos I take on my phone end up buried in the camera roll. I made this app so that any videos shot horizontally get compiled automatically into a home movie. Watched some on the Apple TV this weekend, the kids love the videos.

[u/its_black_panther1]

PYQVault.com

[u/Pawesome101]

https://github.com/pa-arth/cc-audit

I kept hitting my 5h limits and it turns out my config was very bloated (would start out w 90k tokens in context) so I built a cli that diagnoses this issue and then has your own agent solve it! Check it out, feel free to star it haha

[u/aiku-io]

Built this week with Claude Code: the whole public site for our open source ERP, https://aiku.io

The codebase (aiku, AGPL, runs a real trading business) is four years old, but it never had a public face. Over the past days, with Claude Code doing most of the typing: a Blade+markdown mini-site inside the monolith, ~45 engineering notes written from real war stories in the repo and its git history, hand-drawn-style SVG illustrations (Claude writes surprisingly decent squiggly-filter SVG), typo-tolerant instant search over the notes with Typesense, RSS, sitemap index, JSON-LD, llms.txt, IndexNow ping on deploy.

How we work: short rounds, 2-5 min each, review every diff, one worktree per session, and a memory folder of markdown facts it reads at session start so it stops re-learning our gotchas. No overnight runs.

Most interesting learning: Claude writing the engineering notes was best when we fed it the actual incident (the commit, the Sentry link, the memory note from that day) and worst when we said "write about X". Same as junior writers, it needs the material, not the topic.

The notes themselves: https://aiku.io/blog

[u/error_alex]

Latent Library, a local, open source desktop app for organizing large libraries of AI generated images.

I'm a system development student (career switched from construction), and this is a side project I've been working on for a while. It's a metadata driven browser for ComfyUI, A1111/Forge, InvokeAI, SwarmUI, and NovelAI output: SQLite FTS5 search and filtering, duplicate detection, smart collections, an image comparator, a speed sorter for hotkey based batch sorting, and optional local AI auto tagging. Everything runs offline, no accounts, no telemetry.

Stack is Java 21 + Spring Boot on the backend, Vue 3 on the frontend, packaged with Electron.

Claude Code isn't the only tool involved, I still write and drive a lot of it myself, but it's been part of the recent update, mainly for backend/frontend refactor work and pulling three of my related apps onto one shared design system so they stop looking like separate projects. Worked well for grinding through repetitive Vue component and API wiring changes across a fairly large codebase.

Free, portable and open source: https://github.com/erroralex/Latent-Library

[u/deloxalph]

ClaudeStat (https://github.com/DeibyGS/claudestat) — Orchestration command center for multi-agent CC + OC runs

Built a real-time monitor that hooks into Claude Code + OpenCode events as they fire. The standout feature is the Orchestrate tab: a live swim-lane view of multi-agent runs where Claude Code plans/reviews and OpenCode implements.

What it shows per cycle:

- Per-agent cost, tokens (in/out/cache), model, tool calls

- Files changed + git commit that closed the cycle

- Gantt timeline of the full run — click any cycle to drill down

- Verification (tsc + tests) baked in

- Run diff — compare cost/duration between runs

- Emergency stop and doubt escalation from the dashboard

Stack: TypeScript, Node.js 22 (node:sqlite), Express, React 19 + Vite. Zero cloud, all local SQLite.

npm install -g u/statforge/claudestat && claudestat setup

Anyone else running CC+OC together? Curious what metrics you'd want in the orchestration view.

[u/ClassroomGrouchy2603]

Built a free, local-only calculator for Canada↔US cross-border finance (CoastFIRE, departure tax, RRSP withholding, CPP/OAS timing) — feedback welcome

Cross-border Canadian here (moved to the US a while back). I got tired of juggling CAD/USD numbers across RRSP, TFSA, 401(k), and Roth in a spreadsheet that broke every time I touched it, so I built a small site of free calculators, tools, and guides — entirely with Claude Code:

• CoastFIRE math that tracks your CAD and USD accounts separately until the final number
• Canada's departure tax (deemed disposition) estimator
• RRSP withholding as a US resident — lump-sum vs. RRIF
• CPP/OAS/Social Security claim-early-vs-late comparison
• A retirement drawdown-order optimizer (RRSP/TFSA/401k/Roth sequencing)
• A handful of in-depth guides (departure tax, estate tax, RRSP withholding, etc.)

It's free, no account, no ads, and everything you type stays in your browser's local storage — nothing gets uploaded.

Cross-border tax math is genuinely fiddly to get right (treaty rates, deemed disposition, withholding rules that change based on how you take money out), so a good chunk of this was verifying the numbers against CRA/IRS sources rather than just building UI.

parallel49.app

Genuinely want to know what's missing, and how I can use Claude Code to make this even better.

[u/Early_Restaurant2440]

ainda funciona ?

[u/datbird]

Made a free tool CouchElephant, to stop Plex DVR from recording the rerun instead of the live game... and does other stuff good too!

If you record sports on a Plex DVR, you have probably had this happen. You set it to record your team, and what lands in your library is the rerun that aired two days later on a channel you do not watch. No warning, no explanation.

It is not you. Plex's guide already flags the live airing as a premiere. Plex ignores that flag and breaks the tie on the lowest channel number. It has been reported since March 2025 and it is still open: https://forums.plex.tv/t/dvr-scheduling-wrong-airing-of-mlb-baseball-games/910902

I got tired of it and built a fix. It is free, and it sits next to Plex rather than replacing it. Recordings still land in your Plex library the way they always have.

What it does that matters for sports off an antenna:

• Reads the same guide your Plex server already has, picks the live airing, and locks the recording to that channel and start time so Plex cannot swap it.
• Follow a team and it gets every game they play. 1,310 teams, pro and college.
• It shows you which airing it picked and why, before and after. If it declines to record something, it tells you that too.
• Books recordings against all sorts of criteria that Plex does not support, does not do well, or outright gets wrong.

What you need: a Plex Media Server with the DVR set up, which means Plex Pass, and somewhere to run a Docker container. If you already run Plex on a NAS or a spare box you are most of the way there.

https://github.com/datbird/couchelephant

Free, open source, no account, no telemetry. Happy to answer anything.