{"slug": "i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt", "title": "I bundled 80 boring-but-essential dev utilities into one API (QR, invoices, JWT, i18n, Japanese text)", "summary": "A developer has bundled 80 common development utilities—including QR code generation, JWT signing, invoice creation, and Japanese text conversion—into a single API called Toolbelt API. The service requires no AI inference, making it fast and deterministic, with authentication handled through a single header. It also includes specialized Japanese text normalization features such as full-width to half-width conversion and kana to romaji transliteration.", "body_md": "Dev.to / Hashnode / Medium. The frontmatter works on Dev.to as-is.\n\nReplace`{...}`\n\nplaceholders before publishing.\n\nEvery app needs the same dull little jobs: generate a QR code, hash a string,\n\nvalidate an email, format some JSON, build an invoice. I got tired of pulling a\n\nnew dependency for each one, so I put **80 of them behind a single API**:\n\n[Toolbelt API](https://rapidapi.com/ded81908cell/api/toolbelt-api-qr-code-invoice-json-jwt-i18n-utilities).\n\nNo AI, no inference cost — so it's **fast, cheap and deterministic** (same input,\n\nsame output, every time).\n\nAuth is a single header. Here's a QR code:\n\n```\ncurl -X POST \"https://toolbelt-api-9oll.onrender.com/v1/qr\" \\\n  -H \"X-RapidAPI-Key: {KEY}\" \\\n  -H \"X-RapidAPI-Host: toolbelt-api-9oll.onrender.com\" \\\n  -H \"Content-Type: application/json\" \\\n  -d '{\"text\":\"https://example.com\",\"format\":\"svg\"}' > qr.svg\n```\n\n**Validate anything**\n\n``` php\n-d '{\"value\":\"DE89370400440532013000\"}'   # POST /v1/validate/iban -> {\"valid\":true,...}\n```\n\n**Sign a JWT**\n\n```\n-d '{\"payload\":{\"sub\":\"123\"},\"secret\":\"s3cret\",\"alg\":\"HS256\"}'  # POST /v1/jwt/sign\n```\n\n**Convert data formats**\n\n```\n-d '{\"from\":\"json\",\"to\":\"yaml\",\"data\":\"{\\\"a\\\":1}\"}'             # POST /v1/convert\n```\n\n**Build an invoice (SVG, totals auto-computed)**\n\n```\n-d '{\"number\":\"INV-001\",\"currency\":\"USD\",\"taxRate\":10,\n     \"from\":{\"name\":\"My Co.\"},\"to\":{\"name\":\"Client\"},\n     \"items\":[{\"description\":\"Service\",\"quantity\":2,\"unitPrice\":100}]}'  # POST /v1/invoice\n```\n\nThis is the part you won't easily find elsewhere — full-width⇄half-width,\n\nhiragana⇄katakana, and kana→romaji:\n\n``` php\n-d '{\"text\":\"とうきょう\",\"operation\":\"romaji\"}'   # POST /v1/jp/convert -> {\"result\":\"toukyou\"}\n```\n\nIf you build anything for Japanese users (e-commerce, forms, search), normalising\n\nfull-width/half-width input alone saves a surprising amount of pain.\n\n``` js\nconst res = await fetch(\"https://toolbelt-api-9oll.onrender.com/v1/hash\", {\n  method: \"POST\",\n  headers: {\n    \"X-RapidAPI-Key\": \"{KEY}\",\n    \"X-RapidAPI-Host\": \"toolbelt-api-9oll.onrender.com\",\n    \"Content-Type\": \"application/json\",\n  },\n  body: JSON.stringify({ input: \"hello\", algorithm: \"sha256\" }),\n});\nconsole.log((await res.json()).hash);\npython\nimport requests\nr = requests.post(\"https://toolbelt-api-9oll.onrender.com/v1/qr\",\n    headers={\"X-RapidAPI-Key\":\"{KEY}\",\"X-RapidAPI-Host\":\"toolbelt-api-9oll.onrender.com\"},\n    json={\"text\":\"https://example.com\",\"format\":\"png\"})\nopen(\"qr.png\",\"wb\").write(r.content)\n```\n\nQR & barcodes · invoices · Markdown→HTML · JSON/YAML/CSV · hashing · JWT · bcrypt ·\n\nUUID/ULID/NanoID · email/IBAN/credit-card validation · phone (E.164) · postal codes ·\n\ncurrency · color/contrast · units · timezones · geo distance · CIDR · regex tester ·\n\nuser-agent parser · PII redaction · and the Japanese pack.\n\nThere's a free tier — kick the tyres here 👉 [https://rapidapi.com/ded81908cell/api/toolbelt-api-qr-code-invoice-json-jwt-i18n-utilities](https://rapidapi.com/ded81908cell/api/toolbelt-api-qr-code-invoice-json-jwt-i18n-utilities)\n\nIf a utility you need is missing, drop a comment. I ship requested endpoints fast.", "url": "https://wpnews.pro/news/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt", "canonical_source": "https://dev.to/_dekopon13455/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt-i18n-japanese-5799", "published_at": "2026-06-03 07:05:15+00:00", "updated_at": "2026-06-03 07:11:06.725260+00:00", "lang": "en", "topics": ["ai-tools"], "entities": ["Toolbelt API", "RapidAPI"], "alternates": {"html": "https://wpnews.pro/news/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt", "markdown": "https://wpnews.pro/news/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt.md", "text": "https://wpnews.pro/news/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt.txt", "jsonld": "https://wpnews.pro/news/i-bundled-80-boring-but-essential-dev-utilities-into-one-api-qr-invoices-jwt.jsonld"}}