medium 🛠️ Agentic Eng
The Overflowing Grid
A developer is building a puzzle platform. One puzzle page shows a **two-column layout**: a wide main content area on the left and a sticky sidebar...
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20 challenges insane 🛠️ Agentic Eng
The ENV That Disappears At Build Time
Your Next.js app uses `NEXT_PUBLIC_API_URL` in the browser. Works in dev. In production on Vercel, it's `undefined`. You've set it in Vercel's dash...
insane 🛠️ Agentic Eng
The Cascading Delete That Wasn't
You delete a user. No error. But their orders, reviews, and sessions are still in the database — completely orphaned. The Rails migration clearly s...
insane 🛠️ Agentic Eng
Webpack Bundle: The 4MB Surprise
Your production bundle is 4.2MB. Budget is 500KB. The bundle analyzer reveals that 67% of it is `aws-sdk` — all 2.8MB. Nobody on your team uses AWS...
insane 🛠️ Agentic Eng
The API Key That Works In Postman
Your API key works in Postman. Curl works too. Your React app gets 403 Forbidden. Same key, same endpoint. The Network tab shows... wait, it shows ...
hard 🛠️ Agentic Eng
The Docker Build That Works On My Mac
Your Dockerfile builds perfectly on your M2 Mac. GitHub Actions (ubuntu, x86_64) fails during `npm ci` with a native module compilation error. The ...
medium 🛠️ Agentic Eng
The SQL Join That Inflates Totals
Your customer report query returns correct row counts after GROUP BY, but the `SUM(o.amount)` values are wildly inflated. A customer who spent $500...
hard 🛠️ Agentic Eng
OAuth Redirect URI — The Trailing Slash
Google OAuth login broke after deploying to staging. Error: `redirect_uri_mismatch`. You've added the staging URL to Google Cloud Console. You've t...
hard 🛠️ Agentic Eng
The Migration That Locks The Table
Your Rails migration adds a column with a default value to a table with 12 million rows. Postgres 11+ handles this instantly — no table rewrite nee...
hard 🛠️ Agentic Eng
The Phantom 301 Redirect Loop
Your team migrated from HTTP to HTTPS. The site now redirect-loops infinitely — Chrome shows `ERR_TOO_MANY_REDIRECTS`. You're behind Cloudflare wit...
hard 🛠️ Agentic Eng
N+1 Query From a Single Endpoint
Your `/api/teams` endpoint takes 12 seconds to load. There are only 45 teams. Your Prisma ORM generates efficient `IN` queries for the `include` re...
medium 🛠️ Agentic Eng
The 200 OK That's Actually An Error
Your frontend POSTs to `/api/subscribe` and gets 200 OK. The UI shows "Subscribed! 🎉" But users never receive emails. Turns out the backend always...
hard 🛠️ Agentic Eng
The Rebase That Ate Three Commits
You ran an interactive rebase to clean up your feature branch before merging. After the rebase and force-push, three commits are missing — includin...
medium 🛠️ Agentic Eng
GitHub Actions: The Secret That Isn't
Your CI deploy step suddenly fails. The error says AWS credentials are empty. You check GitHub Secrets — they're there. The workflow file hasn't ch...
medium 🛠️ Agentic Eng
The WHERE Clause That Ate Production
A PM ran a quick SQL update to fix a typo in one company's name. Instead of updating 1 row, it updated all 4,847 rows in the `organizations` table....
hard 🛠️ Agentic Eng
JWT Expired But The Clock Is Fine
Your app's auth breaks for ~30% of users. They log in, get a JWT, and within seconds get 401 Unauthorized. The JWT has a 1-hour expiry. Your backen...
medium 🛠️ Agentic Eng
The CSS Grid That Breaks On Safari
Your product grid looks perfect on Chrome. On Safari (including all iPhones), the grid item images collapse to zero height. Your PM tests on their ...
medium 🛠️ Agentic Eng
Z-Index War: The Modal That Hides
You added a confirmation modal to your app. It works great in isolation, but when triggered from the sidebar, it renders *behind* the sidebar. You'...
medium 🛠️ Agentic Eng
CORS From Hell — The Preflight Mystery
You're building a React dashboard that calls your company's internal API. GET requests work perfectly. But the moment you try to POST a new record,...
medium 🛠️ Agentic Eng
The Button That Wouldn't Click
You're a PM who just shipped a landing page with a big "Get Started" CTA button. Marketing is screaming — the button looks fine but nobody can clic...
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