JSON formatter and validator
Validate and format JSON with two-space, four-space or compact output. Preserve numeric tokens, string escapes, key order and duplicate keys as written.
Local developer tools for JSON, CSV, encoding and time
Format JSON, convert CSV, encode text, inspect Unicode, convert Unix timestamps and calculate SHA-256 in your browser.
Each page includes an interactive tool, a complete worked example, its method and limits, and links to the relevant reference material. Calculations and text conversion run in your browser. You do not need an Ithy account.
Text, data and developer utilities
Base64 text encoder and decoder
Encode Unicode text as standard or URL-safe Base64. Decode valid Base64 back into UTF-8 text with explicit padding and invalid-byte checks.
URL encode and decode
Percent-encode a URL component or decode UTF-8 percent escapes. Choose literal-plus or form-plus interpretation explicitly.
Unix timestamp converter
Convert Unix seconds or milliseconds to UTC and browser-local time. Convert an ISO date-time with an explicit zone back to both timestamp units.
CSV and JSON converter
Convert header-based CSV into JSON objects or flat JSON objects into CSV. Preserve CSV text values and handle quoted commas, quotes and multiline fields.
Text and UTF-8 byte counter
Count UTF-8 bytes, Unicode code points, UTF-16 units, grapheme clusters, lines and whitespace-separated words. Inspect the difference with emoji.
HTML escape and entity decoder
Escape ampersands, angle brackets and quotes, or decode common named and numeric HTML entities once. Render results as text without a live HTML preview.
SHA-256 text checksum
Calculate a SHA-256 digest of UTF-8 text locally. Inspect byte count and compare a supplied hexadecimal checksum without uploading the input.
Choose a tool by the question
Use fraction comparison to establish order, fraction arithmetic to calculate a result, and decimal conversion to express a finite decimal exactly. For percentages, identify whether you need a share of a total or a change from an earlier baseline. These questions use different denominators.
Statistics tools describe the values you supply. A small data set, a convenient average or a good fit does not by itself establish a cause or a reliable prediction. Keep the units, sampling process and evaluation split with your result.
Developer tools operate on text or bytes, depending on the format. UTF-8 byte counts differ from visible character counts, Base64 is reversible encoding, and a SHA-256 digest is a one-way checksum. For time conversion, select seconds or milliseconds explicitly and include a time zone in a date-time input.
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