IBAN Validator: Check an IBAN Before You Send Money
One mistyped character can bounce a payment. Check the country, length and mod-97 checksum of an IBAN before you send it.
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Developer Tools
Base64 Encode and Decode: A Practical Guide
Encode text to Base64 or decode it free in your browser. UTF-8 safe, line breaks tolerated, size and character counts shown, with errors on invalid input.
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Convert CSV to JSON: Keep Types and Headers Right
Convert CSV to JSON free with auto delimiter detection, typed numbers and booleans, duplicate-header handling and 2/4-space or tab output. Runs in browser.
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Decode a JWT Online: Header, Payload and Expiry
Decode a JWT online free. See the header algorithm, payload claims, expiry status in UTC and a readable claim summary. Decoding happens in your browser.
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Format JSON Online: Pretty-Print, Minify and Validate
Format JSON online free: pretty-print with 2, 4 or 8 spaces, minify in one click, and get a clear error for invalid input. Runs in your browser.
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JSON to Go Struct: Generate Types With JSON Tags
Generate Go structs from JSON free. Get int64, float64, pointers for optional fields, json tags, and nested types using only the standard library.
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JSON to Rust Struct: Generate Serde Types From a Sample
Generate Rust structs from JSON free. Get serde derives or Debug/Clone, snake_case fields with rename attributes, Vec and Option types, ready to paste.
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JSON to Zod Schema: Generate a Validator From JSON
Turn JSON into a Zod schema free. Get z.object types with optional, nullable and array handling, plus the inferred TypeScript type and the npm command.
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Build an AI Chatbot Persona That Actually Holds Up
Build a chatbot persona free: system prompt, persona card, guardrails and sample dialogue from one form. No AI API call, and the output is yours to edit.
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ChaCha20 Encryption: Encrypt Text With a Passphrase
Encrypt text with ChaCha20-Poly1305 and a passphrase, free in your browser. Authenticated envelopes, random salt and nonce, and a failure on the wrong key.
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LLM Token Counter: Estimate Tokens, Context and Cost
Estimate LLM tokens, context usage and input cost free in your browser. Compare GPT, Claude, Gemini and Llama windows, with honest limits on the estimate.
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JSON to TypeScript: Generate Interfaces from JSON Instantly
Convert JSON to TypeScript interfaces and types online. Generate clean definitions for your projects.
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