Free Online Developer Tools: JSON, YAML, CSV, XML

Which tool do I need?

Pick the format you have and the one you need. If no single tool does the job, the picker shows which tools to chain, in order.

I have

I need

No single tool does this, but you can chain 2:

CSV → JSON CSV to JSON Converter
JSON → YAML JSON to YAML Converter

JSON Tools

Turn Python dictionaries and raw strings into valid JSON, then format, validate, inspect or compress it. These cover most of the JSON chores that come up while debugging an API.

Python Dict to JSON ConverterPaste a Python dictionary, including tuples, sets or hex literals, and get valid JSON back.ValidationIndent optionsCopy String to JSON ConverterTurn an escaped or raw JSON string into formatted, readable JSON, or minify it, with syntax error detection.Error detectionMinifyFile upload JSON BeautifierAdd indentation and line breaks to compressed JSON so you can read and debug it.BeautifySample inputCopy JSON ValidatorCheck JSON for syntax errors and format it once it passes.ValidationFormatPattern checks JSON ViewerExplore nested JSON as a collapsible tree instead of scrolling through raw text.Tree viewExpand allSample input JSON MinifierRemove whitespace and line breaks from JSON to cut its size before you send or store it.MinifySample inputCopy JSON to One LineCollapse multi-line JSON into a single line for API calls, environment variables or logs.One-line outputCopy

YAML Tools

Format and validate YAML before it breaks a pipeline, and convert it to and from JSON for tools that only read one of the two.

YAML FormatterFormat, validate and minify YAML files up to 5 MB, with configurable indentation, quote style and array format.Indent optionsValidationDownload YAML ValidatorCheck YAML syntax with real-time error messages and convert valid YAML to JSON.Live validationFile uploadDownload YAML to JSON ConverterConvert YAML configuration files to JSON with validation and error detection as you type.Live conversionFile uploadMinify JSON to YAML ConverterConvert JSON to YAML with adjustable indentation, for configs, Kubernetes manifests and CI files.Indent optionsFile uploadDownload

CSV and XML Tools

Move tabular data out of spreadsheets into JSON or XML, and generate an XSD schema from an XML sample.

CSV to JSON ConverterConvert CSV to JSON with delimiter detection, type inference and nested object support.Delimiter detectionDrag and dropDownload CSV to XML ConverterTurn comma-separated data into well-formed XML with custom element names and a live preview.Custom elementsLive previewDownload XML to XSD ConverterGenerate an XSD schema from an XML document, with inferred data types, occurrence rules and namespaces.Type inferenceNamespacesDownload

Code Formatters and Minifiers

Clean up Python and HTML for reading, or strip whitespace and comments from HTML, CSS and JavaScript for production.

Python FormatterRe-indent Python code, apply PEP 8 or Black line lengths and catch syntax errors.PEP 8 / BlackSyntax errorsDownload HTML BeautifierIndent and tidy minified or messy HTML so the structure is easy to read.BeautifyCopy HTML MinifierStrip whitespace and comments from HTML to reduce page weight.MinifyCopy CSS MinifierCompress stylesheets by removing whitespace, comments and redundant characters.MinifyCopy JavaScript MinifierShrink JavaScript files by removing whitespace and comments before deployment.MinifyCopy

Encoding, IDs and Security

Convert text to binary or hexadecimal and back, generate UUIDs, and check how strong a password is.

Text to Binary ConverterConvert text to binary, hexadecimal or octal, with UTF-8 and UTF-16 support.UTF-8 / UTF-16Hex and octalDownload Text to Hex ConverterTurn any string into hex bytes in ASCII, UTF-8 or UTF-16, with separators, uppercase and 0x prefix options.ASCII / UTF-8 / UTF-16Separators0x prefix Hex to Text ConverterDecode hexadecimal values into readable text, or encode text back to hex, with input validation.Decode and encodeValidationCopy UUID GeneratorGenerate RFC-compliant v1, v4 and v5 UUIDs in bulk, then copy them or download a text file.v1 / v4 / v5BulkDownload Password Strength TesterCheck a password against eight rules, from length to keyboard patterns and common passwords, with an estimated time to crack.8 checksTime to crackShow / hide

Every conversion at a glance

The full list of what each tool takes in and what it gives back, including the tools that clean up a file without changing its format.

From	To	Tool
Python dict	JSON	Python Dict to JSON Converter
JSON string	JSON	String to JSON Converter
YAML	JSON	YAML to JSON Converter
JSON	YAML	JSON to YAML Converter
CSV	JSON	CSV to JSON Converter
CSV	XML	CSV to XML Converter
XML	XSD schema	XML to XSD Converter
Plain text	Binary	Text to Binary Converter
Plain text	Hex	Text to Hex Converter
Hex	Plain text	Hex to Text Converter
JSON	JSON, format	JSON Beautifier
JSON	JSON, validate	JSON Validator
JSON	JSON, view as a tree	JSON Viewer
JSON	JSON, minify	JSON Minifier
JSON	JSON, put on one line	JSON to One Line
YAML	YAML, format	YAML Formatter
YAML	YAML, validate	YAML Validator
Python code	Python code, format	Python Formatter
HTML	HTML, format	HTML Beautifier
HTML	HTML, minify	HTML Minifier
CSS	CSS, minify	CSS Minifier
JavaScript	JavaScript, minify	JavaScript Minifier

Your data stays in your browser

The 14 converters and formatters under tms-outsource.com/t/ run entirely in JavaScript on the page. When you paste a config file or upload a CSV, the work happens on your own machine, and the pages don’t make requests with the content you enter. That also makes them fast: there’s no upload to wait for, so results update as you type.

Even so, treat any online tool with the same care as a shared screen. Strip API keys, tokens and real customer records before you paste, and use sample data where you can.

Start from the picker. If you only know the format you have and the one you need, the picker above names the tool or the chain of tools.
Search by task. Press / and type a word such as minify, validate or uuid.
Validate before you convert. Most conversion errors come from invalid input, so run JSON or YAML through a validator first.

Cheat sheets for these formats

Need the syntax rather than a converter? These quick references cover the formats and languages the tools work with.

JSON YAML XML Python HTML CSS JavaScript RegEx All 44 cheat sheets

Format files in your editor

If you’d rather not leave your editor, these step-by-step guides show how to do the same job in Notepad++ and VS Code.

Editor guides

Frequently asked questions

Are these developer tools free?

Yes. All 24 tools are free to use, and none of them asks you to create an account or leave an email address.

Is the data I paste uploaded anywhere?

The 14 tools at tms-outsource.com/t/ do the conversion with JavaScript in your browser, and the pages make no requests with the data you paste. As with any online tool, avoid pasting production secrets such as API keys or real customer data.

How do I convert CSV to YAML?

There is no single CSV to YAML tool, so chain two: convert the file with the CSV to JSON Converter, then paste the result into the JSON to YAML Converter. The tool picker on this page suggests chains like this for other format pairs too.

What is the difference between a formatter and a validator?

A validator checks that the syntax is correct and tells you where it breaks. A formatter rewrites valid input with consistent indentation and line breaks so it is easier to read. The YAML and JSON formatters here also report syntax errors, so you can use them for both jobs.

Is there a file size limit?

It depends on the tool and on how much memory your browser has. The YAML Formatter, for example, handles files of up to 5 MB.

Who builds and maintains these tools?

They are maintained by Bogdan Sandu and published by TMS Outsource, a custom software development company with engineering offices in Belgrade and Bucharest.

About the publisher

These tools are maintained by Bogdan Sandu and published by TMS Outsource, a custom software development company founded in 2014, with engineering offices in Belgrade and Bucharest. If you need a team to build or extend a web or mobile product, see our software development services or get in touch.

Free Developer Tools