DEV Community: ShotaTanikawa

5 Free Developer Tools You Can Use Without Signing Up

ShotaTanikawa — Thu, 02 Apr 2026 00:26:39 +0000

There's a special kind of friction that kills productivity: the signup wall. You need to generate a QR code for a demo, grab a screenshot of a client's site, or validate a list of emails — and every tool wants your email address first.

I built a set of browser-based tools that skip all of that. No accounts, no API keys, no "verify your email" loops. Open the page, use the tool, get your result.

Here are 5 that I use regularly in my own workflow.

1. QR Code Generator

What it does: Generates QR codes from any text or URL with customizable foreground/background colors. Export as PNG or SVG.

When you'd use it: You're building a mobile app and need a QR code pointing to your staging URL for device testing. Or you're preparing slides for a talk and want attendees to scan a link to your repo. Either way, you need it in 10 seconds, not after creating an account on some QR platform.

What it looks like: A clean single-page form with a text input at the top, color pickers for foreground and background, a format toggle (PNG/SVG), and a live preview of the generated QR code on the right. Hit "Generate" and download directly.

Try it -> hookray.com/tools/qrcode

2. Website Screenshot Tool

What it does: Takes full-page screenshots of any URL. Supports PNG, JPEG, and WebP output formats.

When you'd use it: You're writing documentation and need a screenshot of a third-party API's dashboard. Or you're doing a competitor analysis and want to archive how their landing page looks today. Or you just need a quick visual for a PR description. Point it at a URL, pick a format, download the image.

What it looks like: A URL input field with format and viewport options below it. After capturing, it shows the full rendered screenshot with a download button. No watermarks, no "upgrade for full resolution" tricks.

Try it -> hookray.com/tools/screenshot

3. HTML to PDF Converter

What it does: Converts any URL or raw HTML into a PDF with configurable paper size (A4, Letter, etc.) and orientation options.

When you'd use it: You need to turn a styled HTML invoice into a downloadable PDF. Or you're archiving a web page that might change. Or your client asks "can you send this as a PDF?" and you don't want to fight with print stylesheets. Paste the URL or HTML, pick your paper size, get a PDF.

What it looks like: Two input modes — a URL field or an HTML code editor. Below that, paper size and orientation dropdowns. Click convert, preview the PDF inline, and download it. Straightforward, no steps wasted.

Try it -> hookray.com/tools/pdf

4. AI Text Summarizer

What it does: Summarizes long text into a paragraph, bullet points, or a one-line TL;DR. Useful for digesting documentation, articles, or meeting notes quickly.

When you'd use it: You're reviewing a 3,000-word RFC from another team and need to get the gist before a meeting in 5 minutes. Or you're writing release notes and want to condense a long changelog into bullet points. Paste the text, pick a format, get the summary.

What it looks like: A large text area for pasting content, a format selector (paragraph / bullet points / TL;DR), and a "Summarize" button. The output appears below with a copy button. Clean and minimal — no distracting options.

Try it -> hookray.com/tools/summarizer

5. Email Validator

What it does: Validates email addresses by checking format, DNS records, MX records, disposable email detection, and common typo suggestions (e.g., "gmial.com" -> "gmail.com").

When you'd use it: You're building a signup form and want to catch bad emails before they hit your database. Or you're cleaning a CSV of leads and need to know which ones will bounce. Or you just want to check if a domain even has mail servers configured. Paste an email, get a full breakdown.

What it looks like: A single email input at the top with a "Validate" button. Results appear as a checklist: format valid, DNS exists, MX records found, not disposable, no typos detected. Each check shows a green pass or red fail with details. If a typo is detected, it suggests the correction.

Try it -> hookray.com/tools/email-validator

Why No Signup?

I've been on the other side of these tools too many times. You Google "free QR code generator," click the first result, and immediately get hit with a registration form. For a QR code.

These tools are part of HookRay — a developer toolkit I'm building. The philosophy is simple: if a tool takes 10 seconds to use, it shouldn't take 60 seconds to access.

If any of these saved you a few minutes, I'd appreciate a bookmark or a share. And if you have ideas for other tools that should exist without a signup wall, I'd genuinely like to hear them in the comments.

I built a webhook testing tool with 80+ testing guides — here's how

ShotaTanikawa — Mon, 30 Mar 2026 00:03:12 +0000

Building webhook integrations is painful. You set up a test URL, it expires, payloads disappear, and you're left guessing what went wrong.

So I built HookRay — a webhook testing and debugging tool.

What it does

Instant webhook URLs — create a test endpoint in one click, no signup required
Real-time inspection — see every incoming request with parsed JSON payloads
Search & filter — find requests by HTTP method, time range, or body content
Replay — re-send any captured webhook to a target URL for debugging
Team sharing — collaborate with your team on shared endpoints

The tech stack

Next.js 16 (App Router) + React 19
Supabase for auth and PostgreSQL
Stripe for subscription billing
Vercel for deployment
Claude API for AI-powered features

80+ webhook testing guides

I created step-by-step guides for testing webhooks from popular services:

Each guide covers event types, sample payloads, and common debugging tips.

9 APIs on RapidAPI

Beyond the webhook tool, I built a portfolio of developer APIs:

AI SEO Meta Tag Generator — generate optimized meta tags from any URL (try it)
Web Page Summarizer — summarize any page in up to 5 languages simultaneously (try it)
QR Code Generator, Screenshot API, HTML to PDF, Email Validation, and more

Lessons learned

Building is the easy part. I shipped everything in ~2 weeks using AI coding tools. Getting users is 10x harder.
SEO takes patience. 116 pages, proper sitemaps, JSON-LD — and Google has indexed only a handful so far.
Distribution > Product. No one will use your tool if they can't find it.

I'm a solo developer from Japan, trying to build side income from developer tools. Would love feedback or advice from anyone who's done this successfully.

👉 hookray.com

Summarize Any Text with AI - Paragraph Bullets or TLDR

ShotaTanikawa — Fri, 20 Mar 2026 17:39:26 +0000

Summarize Any Text with AI — Paragraph, Bullets, or TL;DR

The AI Text Summarizer API condenses long text into concise summaries using Claude AI. Choose your format: flowing paragraph, bullet points, or a single TL;DR sentence. Supports 5 languages.

Quick Start

curl -X POST https://summarizer-api-zeta.vercel.app/api/summarize \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Your long article text here...",
    "format": "tldr",
    "language": "en"
  }'

Response:

{
  "summary": "The article discusses the key impacts of AI on modern software development.",
  "word_count": 12,
  "original_word_count": 850,
  "compression_ratio": 0.0141,
  "language": "en",
  "format": "tldr"
}

Three Formats

Paragraph (default)

{"format": "paragraph", "max_length": 100}

Returns a flowing prose summary in 1-2 paragraphs.

Bullet Points

{"format": "bullets", "max_length": 100}

Returns key points as a bullet list:

• First key point
• Second key point
• Third key point

TL;DR

{"format": "tldr"}

Returns a single sentence capturing the essence.

Supported Languages

en (English), ja (Japanese), es (Spanish), fr (French), de (German)

Python Example

import requests

article = open("long_article.txt").read()

result = requests.post(
    "https://summarizer-api-zeta.vercel.app/api/summarize",
    json={
        "text": article,
        "format": "bullets",
        "max_length": 50,
        "language": "en",
    },
).json()

print(f"Compressed {result['original_word_count']} words to {result['word_count']} words")
print(f"Compression: {(1 - result['compression_ratio']) * 100:.0f}%")
print(result["summary"])

Use Cases

News aggregation: Summarize articles for digest emails
Content curation: Create previews for link roundups
Document processing: Extract key points from reports
Accessibility: Provide quick summaries for long-form content
Slack/Discord bots: Auto-summarize shared links

Try It

Available on RapidAPI with a free tier.

Built by @ShotaTanikawa

Generate QR Codes with a Free API (PNG & SVG)

ShotaTanikawa — Fri, 20 Mar 2026 16:54:43 +0000

Generate QR Codes with a Free API (PNG & SVG)

Need QR codes in your app? The QR Code Generator API creates customizable QR codes from any text or URL. Supports PNG and SVG, custom colors, and sizes up to 2000px.

Quick Start

POST (JSON body)

curl -X POST https://qrcode-api-eight.vercel.app/api/generate \
  -H "Content-Type: application/json" \
  -d '{"data": "https://example.com", "size": 400}' \
  --output qrcode.png

GET (query params — perfect for img tags!)

<img src="https://qrcode-api-eight.vercel.app/api/generate?data=https://example.com&size=200" />

Yes, you can use it directly in <img> tags. No JavaScript needed.

Options

Parameter	Type	Default	Description
`data`	string	required	Text or URL to encode
`size`	number	300	Image size in pixels (100-2000)
`format`	string	"png"	png or svg
`errorCorrectionLevel`	string	"M"	L, M, Q, or H
`margin`	number	4	Quiet zone (0-10)
`darkColor`	string	"#000000"	Hex color for dark modules
`lightColor`	string	"#ffffff"	Hex color for light modules

Custom Colors Example

curl -X POST https://qrcode-api-eight.vercel.app/api/generate \
  -H "Content-Type: application/json" \
  -d '{"data": "Hello!", "darkColor": "#1a56db", "lightColor": "#f0f4ff", "size": 500}' \
  --output blue-qr.png

Python Example

import requests

response = requests.post(
    "https://qrcode-api-eight.vercel.app/api/generate",
    json={"data": "https://mysite.com", "format": "svg"},
)

with open("qrcode.svg", "w") as f:
    f.write(response.text)

Use Cases

Product packaging: Generate QR codes for product URLs
Event tickets: Encode ticket IDs in scannable QR codes
Business cards: Link to your portfolio or LinkedIn
Restaurant menus: Link to digital menus
Marketing: Track campaign URLs with QR codes

Try It

Available on RapidAPI with a generous free tier (200 requests/month).

Built by @ShotaTanikawa

Capture Website Screenshots with a Simple API Call

ShotaTanikawa — Fri, 20 Mar 2026 16:54:42 +0000

Capture Website Screenshots with a Simple API Call

Need to generate thumbnails, create visual previews, or capture website screenshots programmatically? The Website Screenshot API lets you do it in one HTTP request.

Quick Start

curl -X POST https://screenshot-api-rouge-zeta.vercel.app/api/screenshot \
  -H "Content-Type: application/json" \
  -d '{"url": "https://github.com", "width": 1280, "height": 720}' \
  --output screenshot.png

That's it. You get a pixel-perfect PNG screenshot back.

Options

Parameter	Type	Default	Description
`url`	string	—	URL to capture
`html`	string	—	Raw HTML to render
`format`	string	"png"	png, jpeg, or webp
`width`	number	1280	Viewport width (max 3840)
`height`	number	720	Viewport height (max 2160)
`fullPage`	boolean	false	Capture full scrollable page
`deviceScaleFactor`	number	1	Retina scaling (1-3)
`delay`	number	0	Wait ms after page load

Python Example

import requests

response = requests.post(
    "https://screenshot-api-rouge-zeta.vercel.app/api/screenshot",
    json={"url": "https://example.com", "format": "jpeg", "width": 1920, "height": 1080},
)

with open("screenshot.jpg", "wb") as f:
    f.write(response.content)

Node.js Example

const response = await fetch("https://screenshot-api-rouge-zeta.vercel.app/api/screenshot", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({ url: "https://example.com", fullPage: true }),
});

const buffer = await response.arrayBuffer();
require("fs").writeFileSync("screenshot.png", Buffer.from(buffer));

Use Cases

Social media previews: Generate OG images from URLs
Visual regression testing: Compare screenshots across deployments
Thumbnail generation: Create previews for link directories
Archiving: Save webpages as images
Monitoring: Capture visual state of websites periodically

Try It

Available on RapidAPI with a free tier.

Built by @ShotaTanikawa. Feedback welcome!

Convert Any HTML or URL to PDF with a Simple API Call

ShotaTanikawa — Fri, 20 Mar 2026 05:15:08 +0000

Convert Any HTML or URL to PDF with a Simple API Call

Need to generate PDFs from your web app? Invoices, reports, receipts, or just saving a webpage as PDF? The HTML to PDF Converter API does it in one API call — no Puppeteer setup, no server management, no headless browser configuration.

Quick Start

Convert HTML to PDF

curl -X POST https://pdf-api-mu.vercel.app/api/convert \
  -H "Content-Type: application/json" \
  -d '{
    "html": "<h1>Invoice #1234</h1><p>Amount: $49.99</p><p>Date: 2026-03-20</p>",
    "format": "A4",
    "margin": {"top": "25mm", "right": "20mm", "bottom": "25mm", "left": "20mm"}
  }' \
  --output invoice.pdf

Convert a URL to PDF

curl -X POST https://pdf-api-mu.vercel.app/api/convert \
  -H "Content-Type: application/json" \
  -d '{"url": "https://example.com"}' \
  --output page.pdf

That's it. You get a production-quality PDF back.

Options

Parameter	Type	Default	Description
`html`	string	—	Raw HTML to convert
`url`	string	—	URL to convert
`format`	string	"A4"	A0-A6, Letter, Legal, Tabloid, Ledger
`landscape`	boolean	false	Landscape orientation
`margin`	object	20mm all	Top, right, bottom, left margins
`printBackground`	boolean	true	Include background colors/images

Provide either html or url, not both.

Python Example

import requests

# Generate an invoice PDF
response = requests.post(
    "https://pdf-api-mu.vercel.app/api/convert",
    json={
        "html": """
        <style>
            body { font-family: Arial, sans-serif; }
            .header { border-bottom: 2px solid #333; padding-bottom: 10px; }
            .total { font-size: 24px; font-weight: bold; margin-top: 20px; }
        </style>
        <div class="header">
            <h1>Invoice #2024-001</h1>
            <p>Date: March 20, 2026</p>
        </div>
        <table>
            <tr><td>Web Development</td><td>$2,000</td></tr>
            <tr><td>API Integration</td><td>$500</td></tr>
        </table>
        <div class="total">Total: $2,500</div>
        """,
        "format": "A4",
    },
)

with open("invoice.pdf", "wb") as f:
    f.write(response.content)

print("Invoice saved!")

Node.js Example

const response = await fetch("https://pdf-api-mu.vercel.app/api/convert", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    url: "https://github.com/ShotaTanikawa",
    format: "A4",
    printBackground: true,
  }),
});

const buffer = await response.arrayBuffer();
const fs = await import("fs");
fs.writeFileSync("github-profile.pdf", Buffer.from(buffer));
console.log("PDF saved!");

Use Cases

Invoice generation: HTML template → professional PDF invoice
Report exports: Dashboard data → downloadable PDF report
Receipt generation: Order confirmation → PDF receipt for email
Web archiving: Save any webpage as a PDF document
Resume/CV: HTML resume → PDF for job applications
Legal documents: Terms of service → formatted PDF

Why Not Just Use Puppeteer Directly?

You could. But then you need:

A server to run headless Chromium (1GB+ RAM)
Chromium binary management and updates
Timeout handling, memory leak prevention
Scaling for concurrent requests

Or you can make one API call and get a PDF back. Your choice.

Try It

Available on RapidAPI with a free tier (100 PDFs/month).

Built by @ShotaTanikawa. Feedback welcome!

Generate E-Commerce Product Descriptions with AI (API Tutorial)

ShotaTanikawa — Fri, 20 Mar 2026 04:58:23 +0000

Generate E-Commerce Product Descriptions with AI (API Tutorial)

Writing product descriptions is one of the most tedious parts of running an online store. You need SEO-friendly titles, compelling descriptions, and relevant hashtags — for every single product.

In this tutorial, I'll show you how to automate this with the Product Description Generator API, which uses Claude AI to generate professional product copy in seconds.

What You Get

For each product, the API generates:

3 title options (SEO-optimized, under 60 characters)
3 description options (100-200 words, ready for Shopify/Etsy/Amazon)
15 hashtags (for Instagram/TikTok social selling)

Quick Start

cURL

curl -X POST https://description-api-omega.vercel.app/api/generate \
  -H "Content-Type: application/json" \
  -d '{
    "product_name": "Handmade Ceramic Coffee Mug",
    "category": "Kitchen",
    "features": "Hand-thrown stoneware, 12oz capacity, microwave safe, unique glaze",
    "appeal": "Perfect morning coffee ritual, each piece is one-of-a-kind",
    "tone": "handmade",
    "language": "en"
  }'

Response

{
  "titles": [
    "Hand-Thrown Stoneware Coffee Mug – One of a Kind",
    "Artisan Ceramic Mug – Unique Glaze, 12oz",
    "Handcrafted Coffee Mug – Microwave Safe Stoneware"
  ],
  "descriptions": [
    "Start your morning ritual with a mug that tells a story. Each hand-thrown stoneware coffee mug is crafted with care, featuring a unique glaze pattern that ensures no two pieces are exactly alike...",
    "There's something special about wrapping your hands around a mug that was shaped by human hands...",
    "Elevate your daily coffee experience with this beautifully crafted 12oz stoneware mug..."
  ],
  "hashtags": "#HandmadeCeramics #CoffeeMug #Stoneware #PotteryLove #ArtisanMade #UniqueGlaze #MorningCoffee #HandThrown #CeramicArt #KitchenDecor #CoffeeLover #OneOfAKind #ShopHandmade #PotteryMug #CraftedWithLove"
}

Supported Tones

Tone	Style	Best For
`professional`	Polished, trustworthy	B2B, electronics, professional gear
`casual`	Friendly, approachable	Everyday items, food, casual wear
`luxury`	Elegant, sophisticated	Jewelry, fashion, premium goods
`playful`	Fun, energetic	Kids products, novelty items, games
`handmade`	Warm, artisanal	Crafts, handmade goods, Etsy shops

Supported Languages

en (English), ja (Japanese), es (Spanish), fr (French), de (German)

Japanese Example

curl -X POST https://description-api-omega.vercel.app/api/generate \
  -H "Content-Type: application/json" \
  -d '{
    "product_name": "手編みウールマフラー",
    "category": "ファッション",
    "features": "メリノウール100%, 手編み, 180cm",
    "tone": "handmade",
    "language": "ja"
  }'

Python Example

import requests

response = requests.post(
    "https://description-api-omega.vercel.app/api/generate",
    json={
        "product_name": "Leather Laptop Sleeve",
        "category": "Accessories",
        "features": "Full grain leather, fits 13-14 inch laptops, felt lining",
        "appeal": "Professional look for remote workers and digital nomads",
        "tone": "professional",
        "language": "en",
    },
)

data = response.json()

print("=== Titles ===")
for title in data["titles"]:
    print(f"  {title}")

print("\n=== Best Description ===")
print(data["descriptions"][0])

print(f"\n=== Hashtags ===")
print(data["hashtags"])

Node.js Example

const response = await fetch(
  "https://description-api-omega.vercel.app/api/generate",
  {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      product_name: "Wireless Bluetooth Speaker",
      category: "Electronics",
      features: "IPX7 waterproof, 24hr battery, 360 sound",
      appeal: "Take your music anywhere",
      tone: "casual",
      language: "en",
    }),
  }
);

const { titles, descriptions, hashtags } = await response.json();
console.log(titles[0]); // Best title
console.log(descriptions[0]); // Best description

Batch Processing (Multiple Products)

import requests

products = [
    {"product_name": "Silver Earrings", "category": "Jewelry", "tone": "luxury"},
    {"product_name": "Organic Soap", "category": "Beauty", "tone": "natural"},
    {"product_name": "Kids T-Shirt", "category": "Clothing", "tone": "playful"},
]

for product in products:
    product["language"] = "en"
    resp = requests.post(
        "https://description-api-omega.vercel.app/api/generate",
        json=product,
    )
    data = resp.json()
    print(f"\n--- {product['product_name']} ---")
    print(f"Title: {data['titles'][0]}")
    print(f"Description: {data['descriptions'][0][:100]}...")

Use Cases

Shopify/Etsy sellers: Generate descriptions for new listings in seconds
Dropshipping: Create unique descriptions instead of copying supplier text
Social media: Get ready-made hashtags for Instagram/TikTok product posts
Multilingual stores: Generate descriptions in 5 languages from one input
A/B testing: Get 3 variations to test which converts best

Try It

Available on RapidAPI with a free tier (50 requests/month).

Built by @ShotaTanikawa. Feedback and feature requests welcome!

How to Capture and Inspect Webhooks with a Free API

ShotaTanikawa — Fri, 20 Mar 2026 04:58:07 +0000

How to Capture and Inspect Webhooks with a Free API

If you've ever built a Stripe integration, a GitHub Action, or a Shopify app, you know the pain of testing webhooks during development. You set up an endpoint, trigger an event, and then... where did the data go?

In this tutorial, I'll show you how to use the Webhook Receiver API to capture, inspect, and retrieve webhook payloads — all without setting up any infrastructure.

The Problem

During development, you need to:

Receive webhooks from external services (Stripe, GitHub, etc.)
See what data they're sending
Verify headers, signatures, and payload structure

Most developers use console.log and pray. There's a better way.

Quick Start (2 minutes)

Step 1: Create an Endpoint

curl -X POST https://hookray.com/api/endpoints

Response:

{
  "endpoint": {
    "slug": "a1b2c3d4",
    "expires_at": "2026-03-21T00:00:00Z",
    "request_count": 0,
    "max_requests": 100
  }
}

Your webhook URL is now: https://hookray.com/api/hook/a1b2c3d4

Step 2: Send a Webhook

Point any service to your URL, or test manually:

curl -X POST https://hookray.com/api/hook/a1b2c3d4 \
  -H "Content-Type: application/json" \
  -H "X-Custom-Header: my-value" \
  -d '{"event": "order.completed", "amount": 49.99}'

Response: {"ok": true}

Step 3: Retrieve Captured Data

curl https://hookray.com/api/hook/a1b2c3d4/requests

Response:

{
  "endpoint": {
    "slug": "a1b2c3d4",
    "request_count": 1,
    "max_requests": 100
  },
  "requests": [
    {
      "method": "POST",
      "headers": {
        "content-type": "application/json",
        "x-custom-header": "my-value"
      },
      "body": "{\"event\": \"order.completed\", \"amount\": 49.99}",
      "query_params": {},
      "source_ip": "203.0.113.1",
      "created_at": "2026-03-20T12:00:00Z"
    }
  ]
}

Every header, every byte of the body, every query parameter — captured and stored.

Real-World Example: Testing Stripe Webhooks

# 1. Create endpoint
SLUG=$(curl -s -X POST https://hookray.com/api/endpoints | jq -r '.endpoint.slug')
echo "Webhook URL: https://hookray.com/api/hook/$SLUG"

# 2. Set this URL in Stripe Dashboard → Developers → Webhooks

# 3. Trigger a test event in Stripe

# 4. Retrieve the webhook data
curl -s "https://hookray.com/api/hook/$SLUG/requests" | jq '.requests[0].body' -r | jq .

Python Example

import requests

# Create endpoint
resp = requests.post("https://hookray.com/api/endpoints")
slug = resp.json()["endpoint"]["slug"]
print(f"Webhook URL: https://hookray.com/api/hook/{slug}")

# ... configure your service to send webhooks to the URL ...

# Retrieve captured webhooks
resp = requests.get(f"https://hookray.com/api/hook/{slug}/requests")
for req in resp.json()["requests"]:
    print(f"{req['method']} - {req['content_type']} - {req['created_at']}")
    print(req["body"])

Node.js Example

const BASE = "https://hookray.com";

// Create endpoint
const { endpoint } = await fetch(`${BASE}/api/endpoints`, {
  method: "POST",
}).then((r) => r.json());

console.log(`Webhook URL: ${BASE}/api/hook/${endpoint.slug}`);

// Retrieve captured webhooks
const { requests } = await fetch(
  `${BASE}/api/hook/${endpoint.slug}/requests`
).then((r) => r.json());

requests.forEach((req) => {
  console.log(`${req.method} ${req.content_type} ${req.created_at}`);
  console.log(JSON.parse(req.body));
});

Features

Any HTTP method: GET, POST, PUT, PATCH, DELETE — all captured
Full headers: Every request header is stored
Query parameters: ?key=value pairs are parsed and stored
Source IP: Know where the request came from
Free tier: 100 requests per endpoint, expires in 24 hours
No signup required: Create an endpoint and start capturing immediately

Try It Now

The API is available on RapidAPI with a free tier, or use it directly at hookray.com.

You can also use the web dashboard at hookray.com/app for a visual, real-time view of incoming webhooks.

Built by @ShotaTanikawa. If this helped you, a ⭐ on the API listing would be appreciated!