The tools you reach for daily — JSON formatting, UUID generation, cryptographic hashing. Everything runs in your browser. Your data never leaves your machine.
json-format.dev provides essential developer tools that run entirely in your browser. Your data never leaves your machine — no server requests, no logging, no storage.
The JSON Formatter instantly beautifies raw JSON with syntax highlighting and a collapsible tree view. Validates in real-time with plain-English error messages showing exact line and column numbers.
Generate cryptographically secure UUID v4 (random) or timestamp-based UUID v1 in your browser using crypto.randomUUID(). Bulk generate up to 100 UUIDs, validate any UUID string for RFC 4122 compliance.
Compute MD5, SHA-1, SHA-256, and SHA-512 hashes simultaneously — from text input or by dragging a file. Uses SubtleCrypto for native SHA hashing and SparkMD5 for MD5. No files are uploaded.
Many online tools send your data to a server. That means sensitive API responses, internal JSON payloads, and private config files pass through third-party infrastructure. Every tool on this site processes your data in JavaScript running directly in your browser — zero network requests.