DEV Community • 2026-04-18 14:31

Build an Authorization Server with Bun, Hono, and OpenID Connect

Modern applications increasingly rely on OpenID Connect (OIDC) for secure, standards-based authentication. But most tutorials point you at hosted identity providers. What if you need to run your own authorization server maybe for a microservices platform, an internal tool, or simply to understand how the flow works end to end? In this article we'll build a fully working OIDC Authorization Code F...

0 0
12m read
Newest questions tagged javascript - Stack Overflow • 2026-04-18 14:30

I need to add a unique user functionality in my chatroom app, how can I do it?

I have written a logic for userValidation here it is: the chatroom does not have any database. using socket.io import { users } from './users'; function validateUser(user) { for (let i = 0; i < users.length; i++) { if (users[i].username === user.username) { alert("Username already exists"); } else { // join room socket.join(...

0 0
1m read
DEV Community • 2026-04-18 14:29

How to Build a Certificate Generator with HTML and CSS

Every course platform, bootcamp, and online community eventually needs the same thing: certificates. And most developers reach for one of these solutions: A design tool (Canva, Figma) — manual, doesn't scale PDF generation libraries (PDFKit, pdfmake) — painful layout control Canvas API — powerful but verbose and hard to style A third-party certificate SaaS — expensive and locked-in There's a s...

0 0
7m read
DEV Community • 2026-04-18 14:26

AtCoder Beginer Contest 454 参加記録と解答例（A~D問題）

本記事は、AtCoder Beginner Contest 454 (ABC454) に参加した際の、A〜D問題の復習と解答の備忘録です。コンテスト中に考えた解法の方針や、提出したPythonのコードについて整理しています。 A - Closed interval 配点 : 100 点 問題文 整数 L,R が与えられます。 L 以上 R 以下の整数がいくつあるか求めてください。 制約 1≤L≤R≤100 入力される値は全て整数 自分の解答の方針 そのまま $R-L+1$ で計算します。 提出したコード L, R = map(int, input().split()) print(R - L + 1) B - Mapping ...

0 0
5m read
DEV Community • 2026-04-18 14:26

I shipped a NuGet package, then rewrote it completely. Here's why.

If you work in fintech and process card transactions, you've seen MCC codes. Merchant Category Code- a four-digit number that tells you what kind of business charged the card. 5411 is a grocery store. 5812 is a restaurant. 7995 is a casino. Every product that touches transactions eventually needs to turn these codes into something a human can understand. Cashback rules, spend controls, analytics ...

0 0
4m read
Deploying Under the Moonlight
DEV Community • 2026-04-18 14:25

Deploying Under the Moonlight

There's something magical about a calm night walk that clears your mind. I was out, just enjoying the evening breeze and the peaceful streets. Suddenly, I realized a small but frustrating bug was bothering my personal project. Users were being forced to re-login every time my server restarted. Instead of rushing home to my computer to fix it, I pulled out my phone. I didn't want to break the peac...

0 0
2m read
ActionNode: A Real-Time Sustainability Command Center for Earth Day 2026
DEV Community • 2026-04-18 14:23

ActionNode: A Real-Time Sustainability Command Center for Earth Day 2026

This is a submission for Weekend Challenge: Earth Day Edition What I Built ActionNode — a real-time sustainability dashboard that turns complex environmental data into personal, collective action. The app is built around Earth Day 2026's dual themes: "Planet vs. Plastics" and "Our Power, Our Planet". Rather than a static tips site, I wanted to build something that functions as a ge...

0 0
6m read
DEV Community • 2026-04-18 14:21

Kubernetes Secrets Security: Why Built-in Secrets Fail in Production

This article was originally published on Ciro Cloud. Read the full version here. In 2023, a misconfigured Kubernetes cluster at a major fintech company exposed 50 million customer records. The attack vector: base64-encoded secrets stored in plain text in etcd. Kubernetes secrets security alone cannot protect production workloads. The built-in mechanism was designed for convenience, not confidenti...

0 0
8m read
DEV Community • 2026-04-18 14:18

Trenes de Japón: 28% de pasajeros viajan en riel por política, no cultura

Los trenes de Japón mueven el 28% de los pasajeros del país, una cifra que no tiene comparación en el mundo desarrollado. En Francia el porcentaje cae al 10%, en Alemania al 6.4% y en Estados Unidos apenas al 0.25%. La diferencia es tan grande que un viaje en Japón es cien veces más probable que sea en tren que un viaje equivalente en territorio estadounidense. Con esos números, la red ferroviaria...

0 0
11m read
DEV Community • 2026-04-18 14:16

Kubernetes Cost Waste: How to Cut Idle Resource Spending by 60% in 2026

This article was originally published on Ciro Cloud. Read the full version here. Kubernetes cost waste quietly drains enterprise cloud budgets. In production environments with 50+ namespaces, idle resources typically consume 40–70% of allocated compute spend. The fix isn't adding more nodes — it's smarter resource governance. Quick Answer Kubernetes cost waste stems from three root ca...

0 0
10m read
DEV Community • 2026-04-18 14:13

I built a browser-only tool to remove visible Gemini watermarks

I built a small tool called WatermarkZero to handle one specific case: the visible Gemini watermark that shows up in the bottom-right corner of supported Gemini-generated images. Site: https://watermarkzero.org/ Repo: https://github.com/liuyan-wjy/watermarkzero Most tools I found went in one of three directions: they cropped the corner they pushed the file through a remote server they were va...

0 0
2m read
DEV Community • 2026-04-18 14:09

Building a Digital Agency Hub: How METIS Digital Manages 40+ Web Properties

Managing one website is straightforward. Managing five gets interesting. Managing forty-three across four business entities, multiple tech stacks, and different markets? That requires a system. I run METIS Digital, a digital agency that operates a portfolio of web properties spanning real estate diagnostics, professional training, senior services, AI comparison tools, online calculators, and sust...

0 0
7m read
DEV Community • 2026-04-18 14:05

Argon2id Master Passwords: Securing Your Self-Hosted AI Agent Wallet

Securing AI agent wallets with Argon2id master passwords isn't just about hashing—it's about building defense-in-depth around autonomous systems that can move real money. When your AI agent has direct access to crypto wallets, password security becomes the foundation of a multi-layer protection system that includes session controls, policy enforcement, and human oversight channels. Why M...

0 0
6m read
DEV Community • 2026-04-18 14:05

Built a freelance proposal generator that reads your CV

I got fed up with generic AI proposals so I made PropAI. You paste a job → upload your CV → it writes a personalized proposal in ~30 seconds using Claude. Features added this week: • Auto-fetch job from URL • Writing voice matching (paste any sample of your writing) • Tone / platform / language selectors (paid) Live and free to try (3 uses): https://prop-ai-five-taupe.vercel.app Would love your br...

0 0
1m read
DEV Community • 2026-04-18 14:00

How to Check If You

A friend messaged me last week asking why his documentation site wasn't showing up in ChatGPT's search results. He'd been doing all the right things. Good content, proper meta tags, decent domain authority. Took me about 30 seconds to find the problem. His robots.txt was blocking GPTBot. Not intentionally. His hosting provider's default template included a block on several AI crawlers, and he nev...

0 0
5m read
Building WhiteHat: An Autonomous Ethical Hacking Agent with OpenClaw
DEV Community • 2026-04-18 13:52

Building WhiteHat: An Autonomous Ethical Hacking Agent with OpenClaw

This is a submission for the OpenClaw Writing Challenge Turning OpenClaw into an Autonomous Ethical Hacker What if, instead of manually typing nmap commands and googling CVEs every time, you had a partner? Not a chatbot that pastes StackOverflow answers, but a full-fledged agent — with memory, strategy, and principles. I built WhiteHat — an autonomous agent powered by OpenClaw, specia...

0 0
7m read
DEV Community • 2026-04-18 13:49

Serverless Cold Starts: Why Your Lambda Functions Are Slow and How to Fix Them Permanently

This article was originally published on Ciro Cloud. Read the full version here. Serverless cold starts add 100ms to 10 seconds of latency to your function invocations. In production, that delay destroys user experience, triggers circuit breakers, and forces premature architecture changes that cost six figures. After reviewing 40+ enterprise serverless deployments across AWS, Azure, and GCP over...

0 0
11m read
EarthLens AI: A Multimodal Climate Scientist in Your Pocket, Powered by Google Gemini
DEV Community • 2026-04-18 13:48

EarthLens AI: A Multimodal Climate Scientist in Your Pocket, Powered by Google Gemini

This is a submission for Weekend Challenge: Earth Day Edition What I Built I built EarthLens AI — an intelligent, multimodal environmental analysis platform that acts as a pocket climate scientist for anyone with a smartphone. The platform has four core features: EcoVision — Upload or snap a live photo of any environment (river, forest, urban area, factory). Google Gemini analyze...

0 0
3m read
DEV Community • 2026-04-18 13:46

Nginx vs Traefik vs Caddy: Which Reverse Proxy Should You Pick?

Introduction Choosing a reverse proxy is one of those decisions that seems trivial until you're debugging TLS certificate renewals at 2 AM or trying to figure out why your service discovery isn't propagating. If you're running microservices, your reverse proxy is the front door to everything - and picking the wrong one can cost you weeks of configuration headaches. Here, we'll do a han...

0 0
7m read
DEV Community • 2026-04-18 13:45

I Built a SaaS Analytics Tool That Stores Zero Customer Data: Here's the Architecture

Article Most SaaS analytics tools work the same way: connect your payment provider, we ingest your data, store it in our database, and show you dashboards. Simple, proven, and... a privacy nightmare. When I built NoNoiseMetrics, I went a different route. Session-only architecture: your Stripe data is fetched, processed, and displayed in real time — then discarded. Nothing is persisted ...

0 0
3m read
Previous Next