Forem: fadow

7 Developer Tools I Actually Pay For (And 3 That Are Free)

fadow — Wed, 20 May 2026 02:11:17 +0000

I'm cheap. I use Arch Linux, Neovim, and open-source everything. But some tools are worth paying for. Here's my list.

Paid (worth every đồng)

1. DeepSeek API (~$10/month)

My AI coding agent runs on DeepSeek v4 Pro. Cheaper than GitHub Copilot ($10 vs $19/month). Better for Vietnamese context. I use it through Hermes Agent to build boilerplates, write tests, and debug.

DeepSeek Platform — $0.14/M input tokens

2. Railway (~$5/month)

Full-stack hosting that just works. Docker Compose one-click deploy. Built-in MongoDB + Redis. No YAML hell. No Kubernetes.

Railway — free $5 credit

3. Gumroad (free + 10% fee)

I sell my NestJS/Next.js starter kits here. Free to list. They take 10% only on sales. Built-in email marketing to past customers. PayPal + card payments handled automatically.

Gumroad — free to start

4. Namecheap (~$12/year)

Domains. .dev, .app, .com — pick whatever. I use .gumroad.com for now but will switch when there's more revenue.

Namecheap — domains from $1/year

Free (surprisingly good)

5. Hermes Agent (free, open-source)

AI agent that runs in my terminal. Builds projects, manages Obsidian, schedules cron jobs. It wrote 80% of my starter kits while I was AFK. Works with DeepSeek, OpenAI, Anthropic, local models.

Hermes Agent

6. Obsidian (free)

My second brain. PARA method. Everything I know about NestJS/Next.js/Go lives here. Free. Offline. No vendor lock-in.

Obsidian

7. Neovim (free)

0.12 "Stale Earth" with native LSP. No VS Code. No JetBrains. Instant startup. Full control.

Neovim

Not worth it (tried, cancelled)

Tool	Why I cancelled
GitHub Copilot	$19/month for worse code than DeepSeek
Notion	Slow, online-only, bloated
Vercel Pro	Hobby tier is enough for my scale
Adobe Creative Cloud	GIMP + Inkscape do the job
Grammarly Premium	Free tier catches 90%

Total monthly cost

DeepSeek API:  ~$10
Railway:        ~$5
Domain:         ~$1/month (annual)
Gumroad:        free until sale
─────────────────────
Total:         ~$16/month

$16/month to run a full dev setup with AI coding, hosting, and a storefront. Not bad.

Building a NestJS project? Save 7 hours of setup with my pre-configured starter kit.

Next.js Dark Mode with Tailwind CSS v4 in 5 Minutes

fadow — Mon, 18 May 2026 03:23:50 +0000

Dark mode isn't a "nice to have" anymore — users expect it. Here's the fastest way to add it to a Next.js 16 app with Tailwind v4 and next-themes.

1. Install

npm install next-themes

2. Wrap your app

// app/layout.tsx
import { ThemeProvider } from 'next-themes';

export default function RootLayout({ children }: { children: React.ReactNode }) {
  return (
    <html lang="en" suppressHydrationWarning>
      <body>
        <ThemeProvider attribute="class" defaultTheme="system" enableSystem>
          {children}
        </ThemeProvider>
      </body>
    </html>
  );
}

Key flags:

attribute="class" — toggles .dark class on <html>, Tailwind picks it up
defaultTheme="system" — respects OS preference on first visit
suppressHydrationWarning — prevents React hydration mismatch flash

3. Configure Tailwind v4

Tailwind v4 uses CSS-based config. Add this to globals.css:

@import "tailwindcss";

@custom-variant dark (&:where(.dark, .dark *));

That's it. No tailwind.config.js. No darkMode: 'class'. Tailwind v4 just works.

4. Build the toggle

// components/ThemeToggle.tsx
'use client';

import { useTheme } from 'next-themes';
import { useEffect, useState } from 'react';

export function ThemeToggle() {
  const { theme, setTheme } = useTheme();
  const [mounted, setMounted] = useState(false);

  useEffect(() => setMounted(true), []);

  if (!mounted) return <div className="w-9 h-9" />;

  return (
    <button
      onClick={() => setTheme(theme === 'dark' ? 'light' : 'dark')}
      className="p-2 rounded-md hover:bg-gray-100 dark:hover:bg-gray-800"
    >
      {theme === 'dark' ? '☀️' : '🌙'}
    </button>
  );
}

Why the mounted check? next-themes doesn't know the theme until after hydration (it reads from localStorage). Rendering before mount causes a flash of wrong theme.

5. Use in components

<div className="bg-white dark:bg-gray-900 text-gray-900 dark:text-gray-100">
  <h1>Hello</h1>
</div>

Every Tailwind utility works with dark: prefix. No special components needed.

Bonus: System theme + manual override

defaultTheme="system" means:

First visit → matches OS setting
User clicks toggle → saves preference to localStorage
Next visit → uses saved preference, ignores OS

This is what users expect. Don't force dark mode. Let them choose.

Full setup (dark mode + i18n + auth + dashboard): Next.js Vietnam Starter Kit — $15, ready in 5 minutes.

How to Set Up i18n in NestJS — with Vietnamese Translations

fadow — Fri, 15 May 2026 09:15:07 +0000

Most i18n tutorials stop at English and Spanish. If you're building for Vietnamese users, you need proper tone marks, natural phrasing, and a setup that doesn't fight you.

Here's how I built a NestJS i18n system that auto-detects Accept-Language and returns error messages in Vietnamese or English.

1. Install nestjs-i18n

npm install nestjs-i18n

2. Create translation files

src/i18n/
├── vi/
│   ├── validation.json
│   └── response.json
└── en/
    ├── validation.json
    └── response.json

vi/validation.json:

{
  "EMAIL_INVALID": "Email không hợp lệ",
  "PASSWORD_MIN_LENGTH": "Mật khẩu phải có ít nhất 6 ký tự",
  "USER_NOT_FOUND": "Không tìm thấy người dùng",
  "EMAIL_EXISTS": "Email đã tồn tại",
  "FORBIDDEN": "Bạn không có quyền truy cập"
}

vi/response.json:

{
  "LOGIN_SUCCESS": "Đăng nhập thành công",
  "REGISTER_SUCCESS": "Đăng ký thành công",
  "LOGOUT_SUCCESS": "Đăng xuất thành công"
}

3. Register I18nModule

// app.module.ts
import { I18nModule, HeaderResolver } from 'nestjs-i18n';
import * as path from 'path';

@Module({
  imports: [
    I18nModule.forRoot({
      fallbackLanguage: 'vi',
      loaderOptions: {
        path: path.join(__dirname, '/i18n/'),
        watch: true,
      },
      resolvers: [new HeaderResolver(['accept-language'])],
    }),
    // ... other imports
  ],
})
export class AppModule {}

4. Use in exception filters

// http-exception.filter.ts
import { I18nContext } from 'nestjs-i18n';

@Catch(HttpException)
export class HttpExceptionFilter implements ExceptionFilter {
  catch(exception: HttpException, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const i18n = I18nContext.current();
    const response = ctx.getResponse<Response>();
    const status = exception.getStatus();
    const message = exception.message;

    // Translate if the message is a dot-notation key like "validation.EMAIL_INVALID"
    const translated = i18n?.translate(message) ?? message;

    response.status(status).json({
      statusCode: status,
      message: translated,
      timestamp: new Date().toISOString(),
    });
  }
}

5. Auto-detect language from headers

The Accept-Language header resolver does this automatically. The frontend sends Accept-Language: vi or en — NestJS picks it up. Zero extra code.

Vietnamese-specific gotchas

Tone marks: nest-i18n stores JSON as UTF-8. Vietnamese characters (ắ, ễ, ở) work natively. No special handling needed.
Polite phrasing: Vietnamese error messages should sound respectful. "Vui lòng nhập email" (Please enter email) not "Nhập email" (Enter email).
Placeholders: Use {min} and {max} — they work with nestjs-i18n's interpolation:

  "NAME_LENGTH": "Tên phải có từ {min} đến {max} ký tự"

That's it. Your NestJS API now speaks Vietnamese natively.

If you don't want to set this up from scratch, I built a NestJS Vietnam Starter Kit with i18n, JWT auth, RBAC, Docker, and 36 tests — ready to go.

How I built a NestJS + Next.js starter kit with i18n (vi/en) — and why you should too

fadow — Fri, 15 May 2026 06:12:56 +0000

After setting up the same NestJS backend boilerplate for the Nth time, I realized I was spending 1-2 days just configuring auth, i18n, Docker, Redis, Swagger — before writing a single line of business logic.

So I built two starter kits. Not vibe-coded. Clean code. Tested. Production-ready.

What's inside

🔥 NestJS Vietnam Starter ($8)

JWT auth (access + refresh tokens) + RBAC (admin/user roles)
Bilingual i18n (Vietnamese + English) — auto-detects Accept-Language
MongoDB + Redis + Bull queues
Docker Compose — one command to run everything
Auto-generated Swagger docs
Rate limiting, validation pipes, exception filters
36 tests (unit + e2e) — all green

⚡ Next.js Vietnam Starter ($13)

Next.js 16 App Router + React 19 + Tailwind v4
Dark mode + bilingual i18n
Auth pages (login/register) wired to the NestJS backend
Dashboard, profile page, PayOS payment template
Fully responsive, mobile-first

Tech stack
NestJS TypeScript MongoDB Redis Docker Next.js 16 React 19 Tailwind v4

Why I built this

Most starter kits are English-only. Vietnamese devs building for local markets need i18n from day one, with proper tone marks — not machine-translated garbage. These kits ship with natural Vietnamese translations alongside English.

Also, I got tired of Googling the same setup steps every project.

Try it

No free tier yet. But 7-day no-questions-asked refund if it doesn't save you time.

Built to use. Not to flex.