DEV Community • 2026-04-25 16:00

Anti-Join in MongoDB

SQL databases implement anti-joins—finding rows with no match—through NOT EXISTS. Although anti-join is not a distinct relational algebra operator, it can be derived from set difference and semi-join. A naive implementation that scans both sets to find the complement would not scale, so databases use short-circuit evaluation: the inner scan stops as soon as a match is found or ruled out, because o...

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Hacker News: Front Page • 2026-04-25 15:59

Niri 26.04 was just released (scrollable-tiling Wayland compositor)

Article URL: https://github.com/niri-wm/niri/releases/tag/v26.04 Comments URL: https://news.ycombinator.com/item?id=47902416 Points: 7 # Comments: 3

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DEV Community • 2026-04-25 15:53

I made a swing boat that reacts to doom scrolling

When I was a kid, I tried the swing boat a few times and hated it. It made me dizzy. The kind of dizzy where you are not sure if it is fun anymore. You start slow, then someone keeps pushing, and before you know it you are too high and your stomach does not agree. I got that same feeling recently, but from scrolling. Doom scrolling is that thing you do when you open your phone for no reason and ...

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DEV Community • 2026-04-25 15:53

Finn 💰 — A Personal Finance Assistant That Lives in WhatsApp

This is a submission for the OpenClaw Challenge. What I Built Finn is a personal finance assistant that lives entirely in WhatsApp. No app to install, no dashboard to remember to open — you just message Finn the way you'd message a friend. The problem Finn solves is a real one: most personal finance tools require you to change your habits (log into an app, categorize manually, reme...

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DEV Community • 2026-04-25 15:52

Building a Cryptographically Secure 4-Agent E-Commerce System: A Practical Guide

The Problem: Agent Trust Is Broken by Default Here's a scenario that keeps me up at night: You have a payment agent on your network that accepts POST requests to /charge. It doesn't know if that request came from your order agent, a replayed token, or something else entirely on your network. That's not a theoretical risk. That's an open door. Multi-agent e-commerce systems are the per...

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Hacker News • 2026-04-25 15:52

Show HN: Odozi – open-source iOS journaling app

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DEV Community • 2026-04-25 15:51

Grooming operates over time. Here's how behavioral detection tracks it.

Every system designed to detect child grooming has the same problem: it's looking at the wrong unit of analysis. Grooming doesn't happen in a message. It happens across weeks of messages — a slow accumulation of trust, a gradual shift in conversational register, an escalation in contact frequency that would look unremarkable if you sampled any individual session but reads clearly as a pattern whe...

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Hacker News: Front Page • 2026-04-25 15:51

What's Missing in the 'Agentic' Story

Article URL: https://www.mnot.net/blog/2026/04/24/agents_as_collective_bargains Comments URL: https://news.ycombinator.com/item?id=47902339 Points: 6 # Comments: 0

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DEV Community • 2026-04-25 15:49

TodoMaster Pro — Launch

Revolutionize Your Workflow with TodoMaster Pro In today's fast-paced world, project managers and team leads in tech and creative industries face a common challenge: managing tasks across multiple projects while ensuring collaboration among team members. The struggle to prioritize tasks, meet deadlines, and maintain productivity can often feel overwhelming. Enter TodoMaster Pro—your ult...

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The Dunning-Kruger Effect: Why Your First 6 Months With a Framework Are a Lie
DEV Community • 2026-04-25 15:48

The Dunning-Kruger Effect: Why Your First 6 Months With a Framework Are a Lie

Hi there! I love learning. Who doesn't? I'm a firm believer that learning compounds over time and is the greatest leverage anyone has, in every area of life. But the process of learning has a sneaky trap built into it. You usually start with an idea of what you want to learn and then go searching. Websites, books, videos, online courses — all fair game. At the beginning, everything makes sense. C...

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DEV Community • 2026-04-25 15:46

How AutoGLM Brings AI-Powered Browser Automation to Everyone

*This is a submission for the OpenClaw Writing Challenge What AutoGLM Is and Why It Matters Most automation tools demand that you speak their language — XPath selectors, CSS classes, API schemas, script syntax. AutoGLM flips that equation. Built on top of OpenClaw's browser control infrastructure, it accepts natural language instructions and translates them into browser actions. You de...

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Your Pipeline Is 28.3h Behind: Catching Business Sentiment Leads with Pulsebit
DEV Community • 2026-04-25 15:40

Your Pipeline Is 28.3h Behind: Catching Business Sentiment Leads with Pulsebit

Your Pipeline Is 28.3h Behind: Catching Business Sentiment Leads with Pulsebit We just uncovered a fascinating anomaly in the sentiment data: a 24-hour momentum spike of -0.587 in the business sector. What’s more intriguing is that the English press is leading this conversation with a 28.3-hour head start. In a world driven by rapid information flows, this lag is a wake-up call for anyo...

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DEV Community • 2026-04-25 15:39

The Art of Reverse Prompting

A couple of years ago I had to write documentation for my team's next epic. All the ideas were in my head. POCs done, tradeoffs clear. But nothing was on paper. And the meeting was soon. Staring at a blank page, I tried something that felt a little silly at the time. Instead of telling the AI what to write, I asked it to interview me: I have a plan for the team's next epic. I have done some PO...

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DEV Community • 2026-04-25 15:39

TechHub: System Documentation

TechHub is a professional tech news and bookmark management platform. This guide covers the architecture, API reference, and setup procedures for developers. System Overview TechHub is a full-stack web application built with Next.js 15 (App Router). It serves as a proxy for the Hacker News Firebase API and allows users to manage bookmarks in a local SQLite database using Prisma ORM. 1.1 Technol...

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DEV Community • 2026-04-25 15:36

Git Is Your Seat Belt When You Build With AI

You build with Claude Code or Cursor, the result works, you make one more change, suddenly the app is broken. Login no longer works, a file is empty, something in the database structure is different. Editor undo? Only works for one file. The AI touched eight. Anyone who has lived through this knows what comes next: three to four hours of repair. Anyone who has not lived through it will. There is a...

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DEV Community • 2026-04-25 15:35

Is a Data Science Bootcamp Worth It in 2026?

If you’re typing data science bootcamp worth it into Google, you’re probably stuck between two fears: wasting money on hype, or wasting time learning the “wrong” stuff. Bootcamps can be a fast track, but only if they match your constraints (time, budget, learning style) and your target role (analyst vs ML engineer vs data scientist). What you actually buy with a bootcamp A bootcamp isn...

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Three Known Extensions of E=mc Simulations
DEV Community • 2026-04-25 15:35

Three Known Extensions of E=mc Simulations

Three Known Extensions of E=mc² Simulations Interactive Visualization The rest energy equation E = mc² represents a special case within a broader theoretical framework. When mass is in motion or embedded in external fields, the energy-momentum relation requires additional terms. This interactive visualization demonstrates three distinct extensions: 1. Gravity (Valid...

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My RAG Pipeline Was 84% Confident — And Completely Wrong.
DEV Community • 2026-04-25 15:29

My RAG Pipeline Was 84% Confident — And Completely Wrong.

I built a production-grade RAG system called PrecisionRAG. It combines Self-RAG and CRAG (Corrective RAG) techniques, runs on LangGraph, has hallucination checking, answer revision loops, usefulness checks, corrective re-retrieval before web search fallback - and more. Then I asked it a simple factual question and it gave me a confidently wrong answer. 84% confidence. Fully Supported. 100% usefu...

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Introducing Xim Remote: The Ultimate Free, Open-Source Alternative to AirDroid
DEV Community • 2026-04-25 15:25

Introducing Xim Remote: The Ultimate Free, Open-Source Alternative to AirDroid

🚀 Xim Remote — A Privacy-First, Open-Source Remote Control App for Android Are you tired of bloated, subscription-based remote control apps that lock essential features behind a paywall? I was too. ❌ The Problem with Current Solutions If you've ever searched for a reliable Android remote access app, you already know the situation: "Free" plans come with heavy limitat...

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DEV Community • 2026-04-25 15:24

Building a Self-Operating SaaS: How AI Runs My Company While I Sleep

Building a Self-Operating SaaS: How AI Runs My Company While I Sleep Target [x] Medium (long-form, narrative) [ ] Substack (newsletter) Draft Introduction What if your SaaS could operate itself? I'm building "Jibun Corp" — a Japanese life management platform that competes with 14 different SaaS products simultaneously. From Notion to Slack, from Mone...

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