I bundled 80 boring-but-essential dev utilities into one API (QR, invoices, JWT, i18n, Japanese text)

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.

Dev.to / Hashnode / Medium. The frontmatter works on Dev.to as-is. Replace {...} placeholders before publishing. Every app needs the same dull little jobs: generate a QR code, hash a string, validate an email, format some JSON, build an invoice. I got tired of pulling a new dependency for each one, so I put 80 of them behind a single API : Toolbelt API https://rapidapi.com/ded81908cell/api/toolbelt-api-qr-code-invoice-json-jwt-i18n-utilities . No AI, no inference cost — so it's fast, cheap and deterministic same input, same output, every time . Auth is a single header. Here's a QR code: curl -X POST "https://toolbelt-api-9oll.onrender.com/v1/qr" \ -H "X-RapidAPI-Key: {KEY}" \ -H "X-RapidAPI-Host: toolbelt-api-9oll.onrender.com" \ -H "Content-Type: application/json" \ -d '{"text":"https://example.com","format":"svg"}' qr.svg Validate anything php -d '{"value":"DE89370400440532013000"}' POST /v1/validate/iban - {"valid":true,...} Sign a JWT -d '{"payload":{"sub":"123"},"secret":"s3cret","alg":"HS256"}' POST /v1/jwt/sign Convert data formats -d '{"from":"json","to":"yaml","data":"{\"a\":1}"}' POST /v1/convert Build an invoice SVG, totals auto-computed -d '{"number":"INV-001","currency":"USD","taxRate":10, "from":{"name":"My Co."},"to":{"name":"Client"}, "items": {"description":"Service","quantity":2,"unitPrice":100} }' POST /v1/invoice This is the part you won't easily find elsewhere — full-width⇄half-width, hiragana⇄katakana, and kana→romaji: php -d '{"text":"とうきょう","operation":"romaji"}' POST /v1/jp/convert - {"result":"toukyou"} If you build anything for Japanese users e-commerce, forms, search , normalising full-width/half-width input alone saves a surprising amount of pain. js const res = await fetch "https://toolbelt-api-9oll.onrender.com/v1/hash", { method: "POST", headers: { "X-RapidAPI-Key": "{KEY}", "X-RapidAPI-Host": "toolbelt-api-9oll.onrender.com", "Content-Type": "application/json", }, body: JSON.stringify { input: "hello", algorithm: "sha256" } , } ; console.log await res.json .hash ; python import requests r = requests.post "https://toolbelt-api-9oll.onrender.com/v1/qr", headers={"X-RapidAPI-Key":"{KEY}","X-RapidAPI-Host":"toolbelt-api-9oll.onrender.com"}, json={"text":"https://example.com","format":"png"} open "qr.png","wb" .write r.content QR & barcodes · invoices · Markdown→HTML · JSON/YAML/CSV · hashing · JWT · bcrypt · UUID/ULID/NanoID · email/IBAN/credit-card validation · phone E.164 · postal codes · currency · color/contrast · units · timezones · geo distance · CIDR · regex tester · user-agent parser · PII redaction · and the Japanese pack. There'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 If a utility you need is missing, drop a comment. I ship requested endpoints fast.