#DevtoTypescript

A LangGraph.js supervisor plans each question, sends it to six specialist agents, checks their findings and writes one cited answer.

Firestore can't OR across fields and wants a composite index per filter combination, so my tracker loads a board's active tickets once and runs filter

If you’ve ever built a fintech application that touches bank data, you likely remember the dark ages...

TL;DR: For a B2B SaaS chat room, publish a periodic full snapshot beside every incremental diff. Put...

A customer-support agent loop can retry tools, and a timeout can hide a successful feature flag...

Mobile users lose signal constantly. Here's how to design API calls and client code that fail safely and never double-submit.

Titan Email has no public API. So I built an MCP server over IMAP/SMTP that lets Claude read, search, triage and draft mail, including GoDaddy-hosted mailboxes.

I built a small Raycast extension - paste invoice JSON, get a formatted HTML/Markdown preview. Zero...

Here's a problem I didn't expect to be the blocker. I had three model seats — ChatGPT, Gemini,...

AI apps charge a flat price but pay a variable cost. How to see cost vs revenue per user with a few lines of code.

A practical distinction between carrying a tenant ID and deciding whether a caller may use it. ...

A media reminder system gets expensive when the send-later horizon exceeds the queue's limit or...

Two profile layers that overlap on exactly one ingredient, a toggle that is deliberately not an involution, and why the implication is written into storage instead of derived at read time.

Six registries, one readdirSync and fifteen hand-typed entries build one sitemap. The filesystem group works only because the file is prerendered, and the hand-written lastmod dates are contradicted by the pages they describe.

461 statically generated pages, no error when one of them stops existing, and a test file that asserts both that URLs exist and that five particular ones do not.

Marketing copy is allowed to be clearer than the app and never kinder. Three mechanisms on one page: call the engine for the sentence, count the list instead of claiming a number, and read your own meta description back into your structured data.

Eight head terms, eight collection pages, and a measurement that killed the idea: every collection would have contained between 74 and 100 percent of the same library.

I built a rich-text editor from scratch. No ProseMirror, no dependencies. Almost every...

A 14-file UI kit, five Radix packages, 696 uses of one component and 371 hand-written button elements. I counted all of it, then asked a browser what the live pages actually contain, and the answer explains the design system better than the code does.

Two tests can pass while applyDiscount(100) returns 100 instead of the ticket's 90. One replaces the...