Text and Developer Tools That Never Upload Your Data
Why it matters that JSON formatters and text tools run locally, and what each of these actually does.
Most online JSON formatters POST your data to a server. People paste API responses into them — responses that routinely contain access tokens, customer records and internal identifiers.
Every tool below runs entirely in your browser. You can verify it: open developer tools, select the Network tab, and use any of them. No request is made.
Developer tools
JSON
- JSON Formatter — indent at 2, 4, tab, or minify. When parsing fails it reports the line, the column, and the surrounding text, then lists the usual culprits.
- JSON Validator — valid or not, plus type, key count and nesting depth. Uses the browser's own parser, so the answer matches exactly what your code will do.
- JSON to CSV — for getting API data into a spreadsheet. Columns are the union of all keys, so records with differing fields still line up.
The four things that make JSON invalid, in order of frequency: a trailing comma before }
or ], single quotes instead of double, unquoted keys, and unescaped newlines inside strings.
Valid JavaScript is frequently invalid JSON.
Encoding
- Base64 — encode and decode, with full Unicode support. Base64 is not encryption. It is fully reversible by anyone with no key, so never use it to protect anything.
- URL Encoder/Decoder — two modes that matter.
Component encoding escapes
/ ? & = #too, which is right for a value going into a query string. Full-URL encoding preserves those, which is right for a whole address. Using the wrong one is why links break.
Text tools
- Word Counter — words, characters, sentences, paragraphs, plus reading time at 238 wpm and speaking time at 140 wpm.
- Character Counter — including code points, which is how X counts (an emoji is one character, not two), UTF-8 bytes, and checks against the 60-character title and 160-character meta description thresholds.
- Case Converter — nine forms at once: upper, lower, title, sentence, camel, Pascal, snake, kebab and constant case.
- Remove Duplicate Lines — with options for case, whitespace, blanks and sorting. The first occurrence is kept, so original order survives.
- Reading Time Calculator — at several speeds.
On the 238 words-per-minute figure
It comes from a 2019 meta-analysis of reading-rate research: roughly 238 wpm for silent reading of English non-fiction prose. Fiction reads a little faster, technical material considerably slower. If you add "5 min read" labels to articles, round to the nearest minute — the precision implied by "4 min 37 sec" is not real.