TOPSCINET Tools

    Free Online Developer Tools

    The everyday encoding, formatting and debugging utilities, without installing anything or pasting your data into someone else's server.

    100% client-side. Nothing is uploaded.No signup required

    All Developer tools

    JSON FormatterFormat, validate, and minify JSON with syntax highlighting.Base64 Encoder/DecoderEncode or decode text and files to/from Base64.URL Encoder/DecoderEncode or decode URLs for safe transmission.HTML Entity EncoderEncode special characters to HTML entities and vice versa.Regex TesterTest and debug regular expressions with live matching.Hash GeneratorGenerate MD5, SHA-1, SHA-256, and other hash values.UUID GeneratorGenerate unique UUIDs in various versions.Binary ConverterConvert between binary, decimal, hexadecimal, and octal.Favicon GeneratornewGenerate favicons from images, text, or emojis with all sizes.CSV to JSON ConverternewConvert CSV to JSON and back, correctly handling quoted commas, newlines and escaped quotes.JWT DecodernewDecode a JWT's header and payload, with expiry shown as a real date and a live status.

    About these tools

    These are the small utilities that interrupt real work: pretty-printing a minified JSON payload to find the one wrong field, decoding a Base64 blob from a log, checking whether a regex actually matches the edge case you are worried about, or generating a UUID for a test fixture. Each one is a single-purpose page that loads fast and does one job well. There is no editor to configure, no account to create, and no rate limit. The privacy point matters more here than elsewhere. Developers routinely paste API responses, tokens, config fragments and production log lines into online formatters, data that should never touch a third-party server. Everything on this page is client-side JavaScript, so what you paste stays in your browser tab.

    Frequently asked questions

    Is it safe to paste API responses or tokens into these tools?

    Safer than most alternatives, yes. Every tool here runs entirely in your browser with no network request, so pasted data is never transmitted or logged. That said, always rotate any credential that has been exposed, wherever it was pasted.

    How do I format and validate JSON?

    Paste it into the JSON Formatter. It pretty-prints valid JSON with indentation, and reports the location of the problem when the JSON is malformed. It can also minify.

    What hash algorithms are supported?

    The Hash Generator produces MD5, SHA-1, SHA-256 and other common digests. Note that MD5 and SHA-1 are broken for security purposes and should only be used for checksums, not passwords.

    Do these tools work offline?

    Once a page has loaded, the processing itself needs no connection because it runs locally. You will still need a connection to load the page initially.