35 free developer tools that run entirely in your browser — no signup, no uploads
Two things always bothered me about the usual "paste your JSON here" websites: half of them quietly upload your data to a server, and the other half drown you in ads. When you are pasting an access token into a JWT decoder, "where does this data actually go?" is not a paranoid question. So we built a collection of developer tools where everything runs in your browser . No account, no uploads, no…
When working with developer tools that require pasting JSON, JWTs, cron expressions, regex patterns, SQL queries, UUIDs, hashes, base64 data, diffs, or timestamps, traditional methods often involve uploading data to servers or dealing with intrusive ads. However, a collection of entirely browser-based developer tools eliminates these concerns by performing computations directly in your JavaScript environment, ensuring your data remains local and unshared.
Among the ten most frequently utilized tools in this collection, the JSON Formatter stands out for its ability to format, validate, and minify JSON while pinpointing the exact character causing errors. The JWT Decoder is particularly useful for debugging authentication flows without transmitting sensitive tokens to external servers.
Cron Parser simplifies complex cron expressions into understandable plain English descriptions, and Regex Tester offers live highlighting and capture group display of matches as you type, all without the need to submit data to third-party services.
SQL Formatter enhances readability of intricate SQL queries for code reviews, supporting multiple dialects. UUID Generator streamlines the creation of random UUIDs in bulk, allowing for easy copying of generated values. Hash Generator computes various hash functions, including MD5, SHA-1, SHA-256, and SHA-512, from either text or files, useful for generating checksums and cache keys directly on your machine.
Base64 Encoder/Decoder handles text and file encoding and decoding, including the often problematic URL-safe variant, ensuring smooth JWT handling. Diff Checker visually compares two text versions side-by-side, highlighting changes to pinpoint modifications in configuration files. Lastly, Timestamp Converter converts between Unix timestamps and human-readable dates, adjusting for time zones, making it a lifesaver for deciphering timestamp logs.
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