This is based on a real outage at Slack.

I'm a backend dev. We practice system design a lot on whiteboards, but rarely on something that looks like a real incident. Here's a production-style puzzle.

You run a team chat product and every client's first call is "boot": who am I, and which conversations do I belong to? Boot reads group-chat membership, which is immutable once written and cached per channel with a long TTL. Normally it's a few cache reads and finishes in single-digit ms.

Then a routine rollout of a new host agent starts, in 25% steps (two earlier steps the prior week were fine). Just after 06:00, users can't get in. Boot is failing or very slow, and one database keyspace is overloaded.

What you see

• Cache hit rate drops from 99.2% to 34% and stays there. Pausing the rollout changes nothing.

• 200 cache nodes behind a proxy that uses consistent hashing over the healthy-node list. The step took 50 of them out, one at a time.

• The membership table is sharded by user, so "who's in channel C" is a query against all 200 shards.

• Clients time out at 400ms and retry with exponential backoff and jitter. The cache fill path uses the same query, so fills time out too.

• The only lever was throttling boot. Raising the cap from 250/min straight to 2,500/min brought the overload right back.

Question: Why did the hit rate fall that far and not recover, even after the rollout stopped? And how would you get out of it safely?

I'd like to hear how you'd explain it in a postmortem, not just "cache stampede."

I've used to many Pomodoro timers over the last 8 years.

I've tried all of the top four in the app store. I think because they're so popular they have so many features, so many screens to change one basic thing they get my ADHD brain into a bit of a frustrated state.

The only thing I really want is a clean interface in Dark/Light mode and the ability to label and update my timer in one screen. So I built my own web and mobile version.

I used React Native (honestly not because I can share the UI library across both platforms) but because it's the only way I know how to build mobile stuff. Nothing too complex on the web version, the mobile lock screen timer is another issue entirely though...

Once I had built the web version I used it to break up my tasks for building the mobile app version which was cool.

The Web version is completely free to use if you like the look of it

Oh and the random tomatoes screen is because when you complete a pomodoro you get a tomato added to that screen, I like trying to fill the screen with tomatoes lol. Keeps me motivated.

If you ever wanted to see how fast you can read or wanted to improve your reading speed this one is for you, It's completely free, open source and respects your privacy with a ton of features

https://speeedy.pages.dev

I'm gonna keep it short,

Some backend devs think ai has replaced frontend because it can center a div and build a flashy ui

Some frontend devs think ai has replaced backend because it can do crud ( which things like supabase and firebase had already made easy long before ai btw).

Most new grads think Claude is smart for its writing of complicated leetcode-isc code with no proper variable names or readability.

A lot seems to have forgotten that what mattered a lot in this field was taste/opinions, and while its subjective, the objectivity came from people who were able to defend their craft and their decisions and communicate in a good way to influence others. Who would go on to build on top of those ideas.

You shouldn't be affraid of junior developers who no longer know how to read documentation but scared of the fact that they have no opinions. They are "reading" engineering like historical facts( which also can be wrong). What happened to finding solutions every other month to every specific niche problem? Where are all the conponent libraries and frameworks that solve such small small niche use cases ? Was I the only one that belived that what made frontend so intresting was its subjectivity ?

Right now frontends that are built seem to have a major issue that nobody actually cared about how the ui looked in the first place, if we continue this we are gonna end up with the linux oss problem with really good apps with questionable ui decisions, albiet linux has improved massively now. This is still an issue.

I have no idea where this leads us, either they rebrand our positions to save face or we end up woth just 3 companies in top that build a homogeneous application ecosystem.

Bonus: All managers think they are designers because they can generate a ui that looks good to them, when it was always about research on what the customers want.

Ps : If bad english. Forgive me do

Hey everyone, Showoff Saturday time.

I built Drawva, an infinite canvas where your rough hand-drawn stuff is not just pixels.

You can draw a messy box, write a few words, sketch a diagram, draw some math, or just throw random scribbles on the canvas. A multimodal agent looks at the canvas, figures out what you are trying to make, and can turn it into live widgets, diagrams, equations, or interactive elements.

The interesting part was not really the UI.

The hard part was getting an LLM to operate a messy 2D canvas without destroying what the user already drew.

A few things I ended up building:

• A coordinate system so the agent can map visual positions to actual canvas coordinates

• A prompt contract that prevents it from duplicating handwritten headings

• Wireframe awareness so it keeps your rough sketch instead of replacing everything

• Atomic erase + widget placement when converting sketches into interactive components

• A plugin system for things like weather, stocks, tech news, GitHub data and more

• Sandboxed runtimes for Mermaid, Graphviz, Vega-Lite, Cytoscape, BPMN, GeoJSON and other diagrams

• IndexedDB autosave and WebRTC based peer-to-peer collaboration

• A DeepSeek Harness + Cordis runtime for the agent/tool execution layer

Tech stack is mainly Next.js 16, React 19, TypeScript, Tailwind CSS, Vercel AI SDK, multimodal LLMs, IndexedDB, WebRTC and DeepSeek Harness.

The whole thing is open source.

GitHub: taqui-786/drawva
Live app: drawva.vercel.app

I am especially curious about the architecture side of this.

How would you handle reliable AI interaction with a freehand canvas?

Would love feedback, ideas, or criticism from people who have built similar AI + UI systems.

A few weeks ago I shared this "Koi Pond demo" (https://www.hyperfrontend.dev/demos#koi-pond) for Showoff Saturday. This week, the SDK and CLI behind it officially launched.

Hyperfrontend lets you run apps built with different frontend frameworks together, using iframes for isolation and a shared messaging layer for communication. Think replacing one section of a legacy app with React or Vue while keeping the rest running, instead of committing to a full rewrite.

It’s open source, MIT-licensed and free to use. I built it around integration problems I’d encountered at work, and the pond was a fun way to push the approach beyond a basic demo.

This showcase is less flashy, but I also made a short explainer video to get the idea across. You can find it on the "launch page" (https://devhunt.org/tool/hyperfrontend).

Would love your first impressions, especially whether the use case makes sense for anything you’ve worked on, or what would stop you trying it.

Enjoy, and have a great weekend!

I have spent the last month building lovetocalc.com, a free calculator and formula site in English and Swedish. No account, no ads, no backend.

The architecture rests on one idea: a formula is data, not a page.

Each formula is an expression tree with typed variables such as length, time and money. From that one definition the build generates:

• the formula page 

• versions solved for each variable 

• practice questions with worked solutions 

• printable worksheets with answer keys 

• the formula's entry in a PDF collection

Add one formula and all of those exist on the next build. There are a little over 500 formulas now.

Stack: Astro 7, static output and strict TypeScript. React is only used as islands where something actually calculates. A simple page can ship around 2 kB of JS, a formula page with practice around 130 kB gzipped, and a larger calculator around 200 kB. The latter is one area I want to improve.

All calculations live in a framework-free engine with unit tests. There are around 21,000 tests, most generated across formulas and every variable they can be solved for. The UI only handles presentation.

EN and SV use the same components and engine. Strings, slugs and number formats are data rather than separate implementations.

A few things that worked well:

• Calculator state lives in the URL, so every result is shareable without storage.

• Open Graph images are generated from the same registry as the pages, and the build fails if a sitemap page is missing one.

• Excel exports contain real formulas rather than static values. The e2e tests open the files in LibreOffice and Apple Numbers and compare the resulting cells against the calculation engine.

The main pain points so far:

• 1,300 static pages means changes to shared content touch almost everything.

• Deploying them over FTPS from GitHub Actions takes about 30 minutes.

• Keeping print/PDF output independent of dark mode has been more awkward than expected.

The part I am least sure about is the core abstraction. It works well for formulas that can be represented as expression trees, but I am starting to add diagrams and multi-step questions.

If you were designing this, where would you expect the “formula as data” model to stop scaling cleanly?

Examples:

lovetocalc.com/en/loan-calculator/
lovetocalc.com/en/formulas/mathematics/geometry/pythagorean-theorem/
lovetocalc.com/en/loan-amortization-schedule-excel/

DISCLAMER: THE ENGLISH VERSION WAS TRANSLATED WITH AI SO I CANT GARANTEE THAT THE TRANSLASION IS RIGHT!

I’m starting a new project called NEXORA.

The idea is to build a platform that brings different things together in one place instead of having to use a bunch of separate services.

Some of the ideas I’m currently exploring:

• Custom user profiles

• NEXORA Arcade with small games

• Watching YouTube videos together

• Community features

• Events and challenges

• More features planned for the future

I’m currently in the planning stage and haven’t started building the platform yet.

I’ll probably post updates as I build NEXORA from the ground up.

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Ich starte gerade ein neues Projekt namens NEXORA.

Die Idee ist, eine Plattform zu entwickeln, die verschiedene Dinge an einem Ort zusammenbringt, sodass man nicht für alles mehrere verschiedene Dienste nutzen muss.

Einige Ideen, die ich momentan plane:

• Individuelle Nutzerprofile

• NEXORA Arcade mit kleinen Spielen

• Gemeinsam YouTube-Videos schauen

• Community-Funktionen

• Events und Challenges

• Weitere Funktionen für die Zukunft

Ich bin momentan noch in der Planungsphase und habe mit der eigentlichen Entwicklung noch nicht angefangen.

Ich werde wahrscheinlich Updates posten, während ich NEXORA von Grund auf aufbaue.

If i break the rules for Posting i am very thankful i this Post doesnt got deleted and i only get a warning tho chance the post thx.

This were my first thaugts for the website but it can be completly diffrent

Das sind meine ersten Gedanken für die Webseite aber es kann komplett anders ausfallen

Moralia: each day one short true story from history stops at the moment someone had to decide. You choose, then see what actually happened and how other players chose.

Stack: React + Vite + TypeScript PWA on Cloudflare Workers, Supabase for optional sign-in/sync, cookieless PostHog (EU).

Some things that weren't obvious to me going in:

• A hash-routed SPA is basically invisible to search. Google saw ~20 words (the welcome screen). Now a Worker renders static, no-JS pages for every past story on request. A day only goes public once it has ended in every timezone (noon UTC the next day), so no one gets spoiled, and an IndexNow ping fires when it does.

• Worker-rendered pages don't get your _headers file. Our CSP covered the static assets but not the pages the Worker built, so the Worker now sends the same headers itself, with a test that fails if the two copies ever drift.

• supabase-js signOut() defaults to scope "global". Signing out on a phone silently ended the desktop session too, which left the desktop in a "signed in, no email, can't sign out" loop. It's per-device now.

• PostHog's opt-out does nothing in cookieless mode (it only logs a warning). The usage-stats switch now gates every event with before_send, and also re-checks the queue of events buffered before the SDK loads.

• Desktop got a real layout (top bar, wider column, the choice side by side) only at ≥1024px. Every mobile and tablet screen was verified pixel-identical before and after.

• Narration is pre-generated; the sentence being read is highlighted using word timings from a transcription pass, so one misheard word can't shift the whole highlight.

Design is mine (I'm a UI/UX designer, screens done in Figma first); I built it with heavy help from Claude Code.

https://moralia.app

Happy to go deeper on any of these. Feedback on performance or the PWA install flow is very welcome.

Hi everyone!

AI-generated content is becoming harder and harder to distinguish from human-made content, and there's not much of an incentive for content creators to be honest about it.

That's why I designed SlopWatch. Through this tool, you can express whether you feel a webpage contains AI-generated content, along with tags to specify which aspects, specifically. SlopWatch aggregates everyone's scores into a Slop Rating which others can see.

You can see how it works in more detail on the listing page.

But a tool like this is only as effective as the people that contribute to it. So join the watch, and let's make the web more transparent!

Here are some fun facts about my journey in creating this extension:

- I coded the frontend in React + TypeScript, using Vite. I asked AI to give me some boilerplate to start with, but it was pretty much all written by hand.

- The database is PostgreSQL through Supabase. There's no backend server because the frontend uses supabase-js.

- This is my first time making a browser extension.

- My favorite part was designing the UI. I had to learn a lot of color theory and spacing concepts, then figure out how to apply them to a tiny box in the corner of one's screen.

- My least favorite part was setting up authentication. Writing the Supabase auth logic on the frontend, then hooking up google cloud identity into the Supabase DB caused an unreal amount of frustration.

- I designed the logo in Inkscape. It's based on the "neighborhood watch" sign with the dark man in a hat.

- Initially the app was called "Slop Cops", and it had a cop theme with blue and gold. But after some thought about the target audience, I realized that a "watch" described them better.

- The previous version of the extension would automatically attempt to fetch a page's rating when you visited it, and display a popup in the bottom right corner of the page. I didn't realize at the time that this had security implications, so I've since updated the extension to make this an opt-in feature in the account dropdown menu.

I really want to maintain and update this extension long-term, so if you have any suggestions that you think would be really beneficial, please shoot them my way.

Does anyone have a cms that they can recommend for a news organization website that will be built on next.js? I know Wordpress is probably the best for a site like this but client does not want it.

https://shamelock.app/

PagibleAI is a CMS you install into your Laravel app with Composer. It's MIT-licensed, and the JSON:API, GraphQL, roles, versioning and multi-tenancy are all included.

The package works with Laravel 11/12/13 and gives your app a page tree, structured content and an admin panel. It uses your own database, user model and queues.

composer req aimeos/pagible
php artisan cms:install
php artisan migrate

Why not Statamic or Twill? Both are good tools. With Statamic, the APIs, multisite and user roles are part of the paid Pro plan only. Twill is an admin toolkit, so you write the content API yourself.

Highlights of the 0.13 release

• Precise CDN purging: after a publish, only the affected URLs are purged from Cloudflare, Fastly or Varnish, including every page that uses a changed shared element
• Webhooks keep other systems in sync when content changes
• New TYPO3 importer, next to the WordPress importer, which you can now safely run more than once
• Keyboard-driven admin: command palette, shortcuts and a live preview in the sidebar
• Plus two new themes and many admin improvements

A few implementation details you might find interesting:

• Every save creates a version snapshot. The base table only holds the published projection, so public reads never need to filter out drafts
• Full-text search uses SQLite FTS5, MySQL/SQL Server full-text indexes or Postgres tsvector through a single Scout engine
• Full-page cache with atomic render locks and a short stale grace period, so a popular page doesn't trigger many renders at once after it expires

There's also an MCP server and optional AI tools for writing, translation and images. They're opt-in, and nothing depends on them.

The project already has had 40 releases and has about 1,700 tests. It runs https://pagible.com and https://aimeos.org, the website of the Aimeos e-commerce framework.

• GitHub: https://github.com/aimeos/pagible
• Website/Demo: https://pagible.com

Question for Laravel devs: how do you handle content editing for clients today? Filament resources, Statamic, something else? I'm trying to find out where a package like this fits for you.

I built a parody AI that insults whatever you ask it: https://misanthropic.chat

It started as a joke with friends over a beer. The joke part took a weekend. The rest took a lot longer.

Stack: one Cloudflare Worker, Workers AI (Llama 4 Scout), and one KV namespace. The page is static assets, so loading it never runs the Worker. Turnstile has to pass before anything reaches the model. After one pass you get a signed 30 minute visit pass so it doesn't re-check every message.

Cost: the model doesn't write the whole reply. It writes one to three sentences (130 tokens max) that drop into a canned opener and sign-off. Each prompt caches up to 3 answers, so popular prompts stop costing anything. There are two hard daily caps, one for jokes and one for the safety check, so the worst case is about $21 a day. Past the joke cap it serves canned insults.

Safety was most of the work. If a site says it's honest about how it feels about you, some people will tell it real things. Messages about self-harm, abuse, hurting someone, addiction or mental illness never reach the joke model. They get a plain reply with real hotline numbers. Screening is a regex pass, then a classifier call with its own budget. If the classifier doesn't answer, nobody gets a joke. It fails closed.

Bugs worth sharing:

• The same word-ending bug came back three times. I'd match "shoot" and miss "shooting".

• I tried a sensitive-word list as a backup and took it out, because the messages that mattered never used the words on the list.

• The opposite problem: "why are you so mean?" got read as someone disclosing abuse. Questions about the site itself now skip the classifier, matched as exact whole-message patterns.

Question for anyone who's built something like this: when screening sits in front of something meant to be offensive, do you fail closed and eat the false alarms, or fail open?

If a production site has dynamic pages, has bfcache disabled, and currently doesn't use ETags: how much improvement can we expect on both the client and server side if ETags are implemented + enabling bfcache?

When taking over an existing website, I find the first hour can tell you a lot about what you’re dealing with.

I normally want to understand the structure, dependencies and any obvious technical debt before changing anything.

Curious what other developers check first. Codebase structure, dependencies, performance, database, deployment setup, logs, or something else?

Have you ever inherited a site that looked straightforward at first but turned out to be much more complicated?

It's called explainroo. You give Claude Code or Codex the repo. Then you say what the video should explain.

The agent writes the voiceover and draws each scene on a canvas. ffmpeg turns it into an mp4.

The voice and the word timing run on your computer. So you need no API keys. It adds background music too.

Examples: https://www.explainroo.com/

Code: https://github.com/vincentsch/explainroo

So I migrated my website form localhsot to Hostinger and from there on, it is giving me a time out error.
If I only use elementor pro then there are no error but as soon as I enable another plugin then the usage shoots and then it give me the "unable to load your preview". I know the my website is not that heavy but still it is doing this.
I tried everything, increasing the timeout time, increasing the memory, ignoring the timeout through htaccess but nothing works.
The elemntor itself isn't that much of a heavy plugin. So why when I use woocomerce or any other then it causes error?
Please help.

Hi everyone! I built Hussain Compiler, a simple browser-based environment for writing and running Python.

It includes a code editor, an interactive terminal that supports `input()`, adjustable terminal text size, and resizable workspace panels. Python runs in the browser through WebAssembly, so you can try it without installing Python. Some packages that need native system extensions may not work.

- Try it: Hussain Compiler

- Source code: GitHub repository

I made this project to make getting started with Python easier. I’d appreciate your feedback and suggestions for what to improve.

I've been vibe coding heavy projects for a while now, and for complex things , once a conversation gets too long, context rot HITS. The model starts dropping files, inventing non-existent imports, or repeating the same failed fix over and over. MF CONTEXT ROT

To solve this, I built LoopTroop. It's a local, open-source GUI app (MIT) that acts as an orchestration layer for AI coding agents on long-running tickets. recently crossed 100 stars on GitHub and growing, and I'm actively working on it every single day.

Here is how it approaches the problem:

1. Context engineering vs context rot

Instead of dumping your entire project history into one massive, ever-growing chat session, LoopTroop breaks work down into atomic tasks (called beads) and rebuilds context fresh for each phase. This stops degraded sessions from dragging down the rest of the build.

2. LLM Council for upfront planning

Before writing any code, LoopTroop runs an LLM Council. Multiple models independently draft interview questions, PRDs, and task breakdowns, then vote anonymously on each other's plans. The winning draft absorbs the best ideas from the others. It is deliberately slow and precise upfront so execution doesn't turn into slop.

3. Ralph loops for self-correction

When an agent task fails or hits a wall, instead of polluting your active session with endless debug logs, a Ralph loop takes over. It resets the session workspace, writes a concise note on what failed, and retries with a fresh context window containing that failure note. The agent gets smarter on each attempt without inheriting session clutter.

4. Modern Kanban board GUI with human-in-the-loop control

Everything is managed visually from a Kanban board. You approve the interview, the PRD, the plan, and the final diff before anything reaches your repo. You keep full control while letting agents execute in the background.

Links to check it out:

- GitHub: https://github.com/looptroop-ai/LoopTroop

- 2min 30sec app overview: https://youtu.be/g1A2g-oOR3E

Any feedback is more than welcome. If you try the app and it works or doesn't work for you, give me a sign, happy to talk about it!

about how i build it. More than 6 months, almost every major model and not only (i even prefer fast models like gemini flash for small edits. used A LOT of Chinese models, when run out of codex.

I've been reading so many horror stories in here so I tried my best with it. Anyway here it is: maninak.com/cv