A complete set of data processing tools that run entirely in your browser. Format and validate JSON, convert between CSV and JSON, encode or decode Base64, percent-encode URLs, generate cryptographic hashes, and create UUIDs. All processing runs locally.
Every tool uses standard browser APIs and runs in memory. Your data is processed locally and the result stays in your tab.
Read the complete data tools guide
JSON payloads have a habit of carrying secrets. An API response includes a bearer token in an Authorization header. A CSV export includes customer email addresses. A Base64 string turns out to be a base64-encoded private key. The whole reason you opened a formatter was to read the contents, which means whatever is in there is content you don't want a third party to log.
Hosted JSON and CSV tools have to receive your data to format it. That data ends up in web server logs, in load balancer logs, sometimes in CDN caches, sometimes in error tracking services if the formatter throws. The site running the tool is one breach away from your data being public.
In-browser tools never receive the data because the browser is doing the work. The JSON you paste sits in a textarea on your screen, gets pretty-printed by JavaScript, and appears in another textarea. The bytes never crossed a network boundary.
The JSON formatter uses the browser's built-in JSON.parseand JSON.stringify, the same parser that runs on every JavaScript engine. Base64 usesbtoa andatob, with a wrapper for handling Unicode correctly. URL encoding usesencodeURIComponent. CSV parsing is a hand-rolled state machine that follows RFC 4180.
Hashing and UUIDs are slightly different: they rely on the Web Crypto API, which is the standardised browser interface to cryptographic primitives. crypto.subtle.digestcomputes SHA-256, SHA-384, and SHA-512 using the browser's native implementation (often hardware-accelerated). crypto.randomUUIDgenerates RFC 4122 v4 UUIDs from a cryptographically secure random source.
| Approach | Processes locally | Setup | Best for |
|---|---|---|---|
| In-browser (this site) | Yes | None | Pasting real API responses, debugging tokens |
| Hosted online formatters | No | None | Sample data, public JSON |
| CLI tools (jq, openssl) | Yes | Install + learn syntax | Scripting, repeated transforms in CI |
For a quick check during development (formatting a webhook payload, hashing a string, generating a few UUIDs for a database seed), in-browser is the fastest option. For anything you want to automate, the CLI tools are the right choice. Hosted formatters are convenient for sample data but should be avoided for anything sensitive.