Small tools for everyday developer work
Webhook tester, JSON fixer, encoders and converters. Fast, private, right in your browser.
Developer tools
Webhook Tester
Unique URL that captures any HTTP request in real time. Lives 24h.
JSON Formatter & Fixer
Validate, format and auto-repair broken JSON. AI explains errors.
JSON → TypeScript / Python / Go
Generate types and models from any JSON.
Unicode Encoder / Decoder
\u escapes, HTML entities, UTF-8 bytes — and find invisible characters.
Base64
Encode & decode text and files, UTF-8 and URL-safe.
URL Encode / Decode
Percent-encoding and a URL parser.
Hash Generator
MD5, SHA-1, SHA-256, SHA-512 for text and files.
JWT Decoder
Decode, check expiry, verify HS256 signatures.
Regex Tester
Live matches, groups, explanations — or let AI write it.
Cron Explainer
Cron in plain English with the next 10 run times.
cURL → Code
Convert cURL to Python, fetch, axios, PHP.
Unix Timestamp Converter
Epoch seconds/ms ↔ human dates.
UUID Generator
v4 and v7, bulk, validate.
What Is My IP
Your public IP, location and provider — or look up any IP.
Payments
HMAC / Signature Debugger
Generate signatures and find out why one doesn't match.
Test Card Generator
Luhn-valid numbers with expiry, CVV, name & address.
Payment Test Cards
Stripe & Adyen sandbox cards for every scenario.
BIN Checker
Card network, issuing bank, country and type from the first digits.
Decline Codes
What 05, 51, 1A, 65 mean and whether to retry.
Chargeback Reason Codes
Visa & Mastercard dispute codes and winning evidence.
MCC Codes
Merchant category code lookup, 250+ codes.
IBAN & BIC Validator
Country, length, checksum, SEPA, bank code.
EU VAT Checker
Validate a VAT ID in the official VIES database.
Currency & Minor Units
Convert currencies and get amounts in minor units for APIs.
Business Days Calculator
T+N settlement and payout dates, skipping holidays.