DEV Community: David | Kordhub

Generating branded QR codes with logo overlay in Python (PNG + SVG)

David | Kordhub — Mon, 06 Jul 2026 13:17:52 +0000

The Problem

Most QR code libraries give you a black-and-white square.
That's fine for internal tools, but if you need branded QR codes
for marketing, packaging, or invoices, you need custom colors,
your logo in the center, SVG output for print quality, and high
enough error correction that the QR still scans with a logo on top.

Why error correction matters for logo overlay

When you put a logo in the center of a QR code, you're covering
part of the data. QR codes have built-in error correction —
level H (30%) means the code can still be read even if 30% of it
is obscured. Always use H when adding a logo.

Generating a branded QR code

POST /v1/generate
{
  "data": "https://yoursite.com",
  "format": "png",
  "size": 500,
  "foreground_color": "#2563EB",
  "background_color": "#FFFFFF",
  "error_correction": "H",
  "logo_url": "https://yoursite.com/logo.png"
}

Response — the data field is base64-encoded PNG:

<img src="data:image/png;base64,iVBORw0KGgo..." />

PNG vs SVG

PNG — best for web, apps, and mobile. Supports logo overlay.

SVG — best for print and packaging. Scales infinitely without pixelation. No logo overlay support.

Validate before generating

POST /v1/validate
{
  "data": "your string here",
  "error_correction": "H"
}

Response:

{
  "valid": true,
  "estimated_version": 4,
  "message": "QR version 4 will be used"
}

Higher version = denser QR. Version 40 is the maximum.

Try it free

500 requests/month, no card required:

https://rapidapi.com/kordhubdev/api/kordhub-qr-code-generator

Feedback welcome — especially if you've found edge cases with logo overlay or very long URLs.

How I protect Discord webhook URLs from being exposed in frontend code

David | Kordhub — Fri, 03 Jul 2026 21:30:35 +0000

The Problem

If you've ever used Discord webhooks in a frontend app, you've probably done something like this:

const webhookUrl = "https://discord.com/api/webhooks/123456/abc..."
fetch(webhookUrl, { method: "POST", body: JSON.stringify(message) })

The problem: that URL is now visible to anyone who opens DevTools.
They can use it to spam your Discord server, send fake alerts,
or simply abuse it until Discord revokes it.

The Solution: Never expose the real URL

The pattern that actually works:

Register your webhook URL once through a secure backend
Get back a safe ID (like whk_abc123)
Use only that ID in your frontend — the real URL never leaves the server

How it works in practice

Register once (server-side or one-time setup):

POST /v1/webhooks
{ "discord_webhook_url": "https://discord.com/api/webhooks/..." }

Response: { "webhook_id": "whk_abc123" }

Send messages using only the ID:

POST /v1/send
{
  "webhook_id": "whk_abc123",
  "content": "New sale: $49.99",
  "title": "Payment received",
  "mode": "auto"
}

The server decrypts the real URL, formats the message into a
clean Discord embed, strips any @everyone/@here spam, and delivers it.
Your frontend never sees the real webhook URL again.

Bonus: automatic spam filtering

Even if someone on your team accidentally sends @everyone in
an automated message, the API strips it before it reaches Discord.

Try it free

I built this as a standalone API available on RapidAPI with a
free tier (200 messages/month, no card required):

https://rapidapi.com/kordhubdev/api/kordhub-discord-webhook-shield-formatter

Would love feedback — especially from anyone who's dealt with
webhook abuse before.

I built 3 free APIs for LLM developers — here's what I shipped and why

David | Kordhub — Wed, 01 Jul 2026 17:23:53 +0000

The Problem

If you've built anything with GPT-4, Claude, or Llama, you've probably run into these:

JSON that won't parse because of a trailing comma or markdown fence
Discord webhook URLs exposed in your frontend code
Needing QR codes dynamically but not wanting to pay per request

I kept hitting these same walls, so I spent a week building three utility APIs to solve them. All three have free tiers on RapidAPI.

1. JSON Repair & Formatter

LLMs don't always return clean JSON. Trailing commas, markdown code fences, truncated objects — all of these break JSON.parse() and crash your pipeline.

Input (broken LLM output):

{ "name": "Pro Plan", "price": 19.00, }

Output (clean JSON):

{ "name": "Pro Plan", "price": 19.00 }

Fast local repair engine first (<5ms, no AI call). Falls back to AI only when the input is too corrupted for local processing.

Free tier: 500 requests/month, no card required.
https://rapidapi.com/kordhubdev/api/kordhub-ai-json-repair-formatter

2. Discord Webhook Shield & Formatter

If you use Discord webhooks in a frontend app, your webhook URL is exposed in source code. Anyone can find it and spam your server.

You register your real webhook URL once — stored encrypted — and get a safe webhook_id instead. Your real URL never touches your frontend again. Auto-strips @everyone/@here spam before anything reaches Discord.

Free tier: 200 messages/month, no card required.
https://rapidapi.com/kordhubdev/api/kordhub-discord-webhook-shield-formatter

3. QR Code Generator

PNG & SVG output, custom hex colors, optional logo overlay. Error correction up to H (30%) keeps the QR scannable even with a logo on top. 100% local processing — no per-call AI cost.

Free tier: 500 requests/month, no card required.
https://rapidapi.com/kordhubdev/api/kordhub-qr-code-generator

Tech stack

FastAPI + Python, hosted on Render. Local engines use open-source libraries (json-repair, qrcode + Pillow) so cost per request is near zero. Groq only kicks in as AI fallback when local processing fails.

Would love feedback on pricing or use cases I missed.
Find me on X: @kordhub