Developer Tools
Everyday utilities for developers. Tidy and validate JSON, convert between JSON and CSV, encode and decode Base64, test a regular expression against real input, turn a Unix timestamp into a readable date, generate UUIDs in bulk and create SHA hashes to compare against a checksum.
Each tool is built for one job and shows clear errors when something is wrong, which makes debugging quicker.
Format and minify See all
JSON Formatter & ValidatorPretty-print, minify and validate JSON with clear error messages.HTML MinifierShrink HTML by removing comments and extra whitespace, with the size saved shown.CSS FormatterBeautify CSS with tidy indentation, one declaration per line and your choice of style.JavaScript FormatterBeautify JavaScript with consistent indentation, spacing and line breaks.Markdown PreviewerWrite Markdown and see a live preview, then copy the matching HTML.JSON Key SorterSort the keys of a JSON object alphabetically, naturally or ignoring case, at every level, without changing any values.SQL FormatterTidy SQL queries with clean indents, line breaks and keyword case.CSS Minifier & BeautifierShrink CSS for faster pages, or spread it out so it is easy to read.JavaScript MinifierStrip comments and spaces from JavaScript and see the size saved.HTML Formatter & MinifierIndent messy HTML for reading, or compact it to cut page weight.XML Formatter & ValidatorPretty print or minify XML and check it is well formed.
CSV and spreadsheets See all
CSV ViewerOpen a CSV as a table you can sort, filter and summarise.CSV CleanerTidy a messy CSV: trim spaces, drop empty rows and columns, straighten curly quotes and clear out hidden characters.CSV Duplicate RemoverRemove duplicate rows from a CSV using the columns you choose, or list only the rows that repeat.CSV Column Extractor and ReorderKeep only the columns you need, put them in a new order and rename them.CSV MergeStack several CSV files into one table, lining the columns up by name.Join Two Tables on a Key ColumnMatch two tables on a shared column and bring across the columns you want, like a look-up.CSV SplitterSplit a large CSV into smaller files by number of rows, number of files or the values in a column.CSV SorterSort a CSV by up to three columns, as text, numbers or dates, in either direction.CSV FilterKeep or remove the rows of a CSV that meet conditions you set, using text, numbers or dates.Pivot Table MakerSummarise a table by one or two fields: totals, counts, averages, smallest and largest.Unpivot Table (Wide to Long)Turn columns such as Jan, Feb and Mar into rows, so the table is ready for pivot tables and charts.CSV Column StatisticsProfile every column of a CSV: type, blanks, different values, sum, mean, median, smallest and largest.CSV to Excel ConverterTurn a CSV into a proper .xlsx workbook with real numbers, dates, a bold header, filters and sensible column widths.Excel to CSV ConverterOpen an .xlsx workbook, pick a sheet and save it as CSV or TSV with dates written as dates.Excel Column Letter ConverterChange column letters to numbers and numbers to letters, for example A to 1, Z to 26, AA to 27 and 16384 to XFD.Excel Date Serial Number ConverterTurn Excel date serial numbers such as 45000 into dates, and dates back into serial numbers.CSV Delimiter ConverterChange a file between comma, semicolon, tab and pipe separators, with control over quoting, line endings and decimal marks.CSV ValidatorCheck a CSV for unclosed quotes, rows with the wrong number of values, bad characters and other faults, with line numbers.Transpose TableSwap the rows and columns of a table so that rows become columns and columns become rows.CSV Find and Replace by ColumnReplace values in chosen columns of a CSV with up to four rules, including whole-cell and pattern matches.Data AnonymiserHide names, emails, phone numbers and other personal details in a table before you share it.Random Sample of RowsPick a random sample of rows from a CSV by number or percentage, optionally from each group, with a seed for repeatable results.Chart Maker from Pasted DataMake bar, stacked bar, line, pie and donut charts from a pasted table and download them as PNG or SVG.Fixed Width to CSV ConverterConvert fixed width text, where columns line up in neat blocks, into a CSV by finding the gaps or setting positions.CSV Column CalculatorAdd a new column worked out from a formula, such as [Price] * [Quantity], with if, round, text and date functions.Compare Two CSV FilesSee what changed between two versions of a table: rows added, removed and cells changed, matched on a key column.Split a Column into Several ColumnsSplit one column into several at a comma, space, dash or fixed width, the way text to columns does in a spreadsheet.CSV Date and Number FixerMake dates and numbers in a CSV consistent: one date format, plain numbers without £, commas or brackets.CSV Value CounterCount how many times each value appears in a column, with percentages, or group numbers into ranges.Fill Blank Cells in a CSVFill empty cells with the value above or below, a fixed value, or the mean, median or most common value of the column.
Data format converters See all
JSON to CSV ConverterTurn a JSON array into a CSV table you can open in a spreadsheet.CSV to JSON ConverterConvert CSV rows into a clean JSON array of objects.SQL INSERT to JSON ConverterTurn SQL INSERT statements into JSON objects, one per row.JSON to TypeScript ConverterGenerate TypeScript interfaces or types from a sample of JSON.CSV to SQL INSERT ConverterTurn CSV rows into SQL INSERT statements, with an optional CREATE TABLE.JSON XML ConverterConvert JSON to XML or XML to JSON, with attributes, repeated elements and line numbers for errors.CSV XML ConverterTurn CSV rows into XML records, or flatten repeating XML records into a CSV table.JSON to Code ConverterGenerate Go structs, Python dataclasses or C# classes from a JSON sample, with optional fields worked out for you.curl ConverterConvert a curl command into fetch, Python requests or axios code.Config File ConverterConvert between JSON, TOML, INI and .env files, with line numbers for any mistakes.JSON FlattenerFlatten nested JSON into single-level keys such as user.address.city, or rebuild the nested form from flat keys.JSON Lines ConverterConvert JSON Lines (one JSON value per line) to a JSON array, or an array to JSON Lines.Query String to JSON ConverterParse a URL query string into JSON with repeated and bracketed keys, or build a query string from JSON.YAML and JSON ConverterConvert YAML to JSON and JSON to YAML, with clear line-numbered errors.
Encoding and escaping See all
Base64 Encode & DecodeEncode text to Base64 or decode it back, with URL-safe output.Text to Binary ConverterConvert text to binary, hexadecimal, decimal or octal numbers and back again.Regex EscaperEscape text so a regular expression matches it exactly, or undo the escaping.Base32 Encoder and DecoderEncode text to Base32 or decode it back, with standard, hex and Crockford alphabets.ASCII TableLook up ASCII codes in decimal, hex, octal and binary, with search.SVG to Data URI ConverterTurn SVG code into a CSS-ready data URI, as encoded text or Base64.URL Encoder & DecoderEncode or decode URLs and query values, and break a web address into its parts.HTML Entity Encoder & DecoderConvert special characters to HTML entities, and turn entities back into ordinary text.String Escape and UnescapeEscape or unescape text for JSON, JavaScript, Python, Java, C#, SQL, MySQL, CSV and shell strings.Line Ending and Tab ConverterConvert Windows, Unix and old Mac line endings, and change tabs to spaces or spaces to tabs, in text or a file.Base58 Encoder and DecoderEncode text or hex to Base58 and decode it back, with the Bitcoin, Flickr and Ripple alphabets and Base58Check.Punycode ConverterConvert internationalised domain names to xn-- Punycode and back, in domains, URLs and email addresses.Text Encoding ConverterConvert text to hex, a hex dump, Unicode escapes or quoted-printable, and back.
Hashes, IDs and tokens See all
UUID GeneratorGenerate random v4 UUIDs in bulk, with format options.Hash GeneratorCreate SHA-1, SHA-256, SHA-384 and SHA-512 hashes of text or files.JWT GeneratorCreate a signed HS256 JSON Web Token from your payload and a secret.UUID ValidatorCheck UUIDs and see their version, variant and creation time where it is stored.JWT DecoderRead the header, payload and expiry times of a JSON Web Token. The signature is not checked.HMAC GeneratorCreate an HMAC signature of a message with SHA-256, SHA-512, SHA-1, SHA-384 or MD5.Checksum CalculatorWork out CRC-32, CRC-16, Adler-32, MD5, SHA-1 and SHA-256 of text, hex bytes or a file, and compare with a published value.Bcrypt Hash GeneratorCreate a bcrypt password hash with the cost you choose, or check whether a password matches a bcrypt hash.Random ID and String GeneratorGenerate ULIDs, NanoID style identifiers or random strings from any characters, and decode a ULID back to its time.
Network and HTTP See all
HTTP Header ParserBreak raw HTTP headers into a readable list, with cache, cookie and type details.URL ParserSplit a web address into protocol, host, port, path, query and fragment.CIDR and Subnet CalculatorWork out the network, broadcast, mask and usable range of an IPv4 subnet.HTTP Status Codes ReferenceSearch the common HTTP status codes, with a plain explanation of each and when to use it.User Agent ParserRead a user agent string to find the browser, its version, the operating system and the device.IP Address ConverterConvert an IPv4 or IPv6 address between dotted, decimal, hex, binary, compressed and expanded forms.IP Range to CIDR ConverterTurn a start and end address into the smallest list of CIDR blocks that covers exactly that range.MAC Address FormatterReformat MAC addresses with colons, hyphens, dots or no separator, upper or lower case, and see the details.MIME Type LookupFind the media type for a file extension, or the extensions for a media type, with its registry status.Common Ports LookupLook up which service uses a network port, or which port a service uses, from a checked list of about a hundred.
Testing and comparing See all
Regex TesterTest regular expressions with live match highlighting.JSON Schema ValidatorCheck JSON data against a schema and see each problem with its path.Side by Side DiffCompare two versions of code or text in two columns with line numbers and highlighted changes.JSONPath TesterTry a JSONPath query against your JSON and see every match with its exact path.Semver ComparatorCompare, sort and bump semantic versions, and test which versions satisfy a range such as ^1.2.3 or ~2.0.JSON DiffCompare two JSON documents and list what was added, removed or changed.
Developer utilities See all
Unix Timestamp ConverterConvert Unix timestamps to readable dates and back.Cron Expression GeneratorBuild a cron schedule from simple choices and see it in plain English with the next five run times.Cron Expression ExplainerTurn a five-field cron schedule into plain English and see its next five run times.chmod CalculatorTick the permissions you want and read the octal and symbolic chmod values, or type a value to see what it allows.HTML Table GeneratorPaste spreadsheet or CSV data and get clean, accessible HTML table code with a live preview.Gitignore GeneratorPick your languages, editors and systems and get a combined .gitignore file with sensible patterns.Bitwise CalculatorApply AND, OR, XOR, NOT, shifts and rotations to numbers of 8 to 64 bits and see hex, decimal, signed and binary results.
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Guides to read first
JSON Explained for Beginners: Syntax, Errors and Formats
JSON explained for beginners: learn the syntax rules, fix the most common errors, format data neatly and compare JSON with CSV and YAML in plain language.
Hex, binary and decimal: how number bases work
How binary, octal, decimal and hexadecimal work, how to convert between them by hand with worked examples, and where each base shows up in real life.
Cron Expressions Explained: Fields, Examples and Pitfalls
Cron expressions explained with field breakdowns, worked schedules, common mistakes such as day-of-week confusion and how time zones affect when jobs run.