TLDR Index
TLDR Dev

TLDR DEV 2026-03-20

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01GENERAL

Sponsored

WHEN IS CODE SECURITY TOO LATE?

There's too much code being generated - and too many bottlenecks at the review and deploy stages. For security to work, it needs to make a big shift to the left.

dev.checkmarx.comSponsor

02ARTICLES & TUTORIALS

HOW OPENAI CODEX WORKS

OpenAI's Codex coding agent uses an "agent loop" that iteratively constructs prompts, interacts with the model, and executes tool calls like running commands or tests until a task is complete. Managing the growing conversation history and layered context is done through prompt caching and context window compaction to maintain performance. To support various interfaces, from CLIs to IDEs, OpenAI developed a bidirectional App Server protocol that encapsulates the core agent logic.

blog.bytebytego.com12 min read

HOW SLACK REBUILT NOTIFICATIONS 📣

Slack's notification system had quietly become a mess due to four conflicting preference models, settings that didn't sync across devices, and no clean way to separate “show me activity” from “push me.” They rebuilt it from scratch into one unified model with a simple three-option structure and a single boolean controlling push, migrating millions of users without downtime using a read-time remapping strategy.

slack.engineering8 min read

03OPINIONS & ADVICE

THINKING BEATS CODING: HOW TO HIRE THE RIGHT ENGINEERS IN THE AI ERA

Hiring engineers based on framework knowledge is increasingly misguided as AI handles more implementation work. The traits that have always separated strong engineers are systems thinking, reasoning about tradeoffs, and clarifying problems before proposing solutions.

blog.logrocket.com4 min read

YOU'RE NOT PAID TO WRITE CODE

A dev's job isn't to write code. It's to solve problems, and the best engineers spend more time questioning requirements than typing. Code is a liability that needs to be maintained forever, so the real win is often writing less of it (or none at all).

newsletter.techworld-with-milan.com6 min read

04LAUNCHES & TOOLS

Sponsored

STOP PUSHING WEBHOOKS TO Q5

With Svix you no longer need to. Learn from Brex: [12] API teams know they need webhooks, but bandwidth and timing often push them out.

svix.comSponsor

STARWIND UI

Starwind UI is a collection of beautiful, accessible components for Astro projects, styled with Tailwind CSS v4, providing a "shadcn-like" experience for Astro developers. It allows users to own and fully customize component source code directly.

starwind.devTool

05MISCELLANEOUS

OPENAI TO ACQUIRE ASTRAL

OpenAI is acquiring Astral and its widely used open-source Python developer tools, such as uv, Ruff, and ty. This acquisition is intended to accelerate the growth of OpenAI's Codex, moving it beyond simple code generation to participate in the entire software development lifecycle.

links.tldrnewsletter.com4 min read

WHY WE BANNED REACT'S USEEFFECT

Factory banned useEffect in their React codebase after production bugs convinced them it's more trouble than it's worth. Dependency arrays hide coupling, effect chains create race conditions, and it's the first thing AI agents reach for when they don't know what else to do. Almost every real useEffect use case has a better primitive: derive state inline, use a data-fetching library, put logic in event handlers, or use a key prop to force remounts.

links.tldrnewsletter.com10 min read