JSON, YAML, XML and CSV tools
Validate and format JSON, YAML and XML with exact error positions, convert JSON, CSV, Excel, YAML, TOML and XML, and compare or open big data files.
- 40 tools
- Free previews, no sign-up
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Go to the 40 toolsReading, fixing and converting structured data
For developers, data analysts, testers and anyone handed a file in a format they need to read or change: an API response that will not parse, a YAML config with a hidden mistake, a CSV that has to become JSON, or a data file too large for a text editor. The tools point to the exact line and column of a problem and keep values exact when they convert.
How to choose
Choose by what you need to do with the data:
Check it: JSON Validator, JSON Schema Validator, YAML Validator & Formatter and XSD Validator.
Read it: JSON Formatter, JSON Viewer & Tree Editor, XML Formatter, JSONPath & JMESPath Tester and Parquet, Avro & Arrow File Viewer.
Fix it: JSON Repair Tool for almost-JSON, and JSON Diff & Compare to see what changed.
Convert it: CSV to JSON Converter, JSON ↔ YAML Converter, XML ↔ JSON Converter, TOML ↔ JSON Converter, Excel to JSON Converter, JSON to Excel Converter and Table Converter.
Load it somewhere: CSV to SQL Converter, Run SQL on CSV & Excel Files and JSON Lines (JSONL / NDJSON) Converter.
Practise or test: Sample CSV & Excel Files and JSON Schema Generator.
XML attributes, YAML comments and spreadsheet formatting do not all survive every conversion, so look at the preview before you rely on the result.
The main tools, compared
| Tool | When to pick it | What you give it | What you get | Works offline | Stays on your device |
|---|---|---|---|---|---|
| JSON Formatter Pro tool | Pretty-prints or minifies JSON, repairs common slips on request and points to the exact place of any error that remains. | Code or JSON | Free preview: the first lines of the formatted or minified JSON (up to 20), with every syntax check, warning and size | Yes | Yes |
| JSON Validator Pro tool | Applies the JSON standard strictly, reports the line, column and reason of the first error, and lists every path in a valid document. | Code or JSON | Free preview: every count and syntax error, with the first warnings and JSON paths of the report (up to 10) | Yes | Yes |
| Sample CSV & Excel Files (Test Data Download) Pro tool | Hands you realistic test spreadsheets in CSV or Excel, at the number of rows you choose, to practise on or to try an import with. | Nothing — start blank | Free preview: the first rows of the file you choose (up to 10, at most half of its rows; a one-row file with its values hidden), with its columns and exercises | Yes | Yes |
| CSV to JSON Converter Pro tool | Converts CSV to JSON and back, detecting the delimiter and keeping numbers, dates and leading zeros typed safely, with a preview table. | Spreadsheet or CSV, Code or JSON | Free preview: the first lines of the converted JSON or CSV (up to 20) and the first rows of its table (up to 10), with the row and column counts | Yes | Yes |
| JSON Viewer & Tree Editor Pro tool | Opens a large JSON file as a fast, searchable tree you can edit, and copies the path of any value you select. | Code or JSON | Free preview: the summary counts of your document and of each search, and the first rows of the tree (up to 10) with their types, sizes and paths | Yes | Yes |
| JSON ↔ YAML Converter Pro tool | Moves documents between JSON and YAML with numbers kept exact, and warns about YAML values such as yes and no that change meaning. | Code or JSON | Free preview: the first lines of the converted YAML or JSON (up to 20), with every warning about your input | Yes | Yes |
| JSON Schema Validator Pro tool | Tests a document against a JSON Schema and lists every failure with its path, its line and how to fix it. | Code or JSON | Free preview: the verdict and every count, with the first problems and schema warnings (up to 10); errors that stop your JSON or schema from being used show in full | Yes | Yes |
| JSON Diff & Compare Pro tool | Compares two JSON documents by structure rather than text, and exports the difference as a JSON Patch or a Merge Patch. | Code or JSON | Free preview: every difference count, the first rows of each view (up to 10) and the first lines of the patch or the patched document (up to 20) | Yes | Yes |
Worked example: finding the mistake in an API response that will not parse
A 58-byte JSON document holds a name, a list of items and a flag, but a client refuses to parse it. The list is written as [1, 2,].
The validator reads the document strictly, as the JSON standard defines it.
On line 3, after the 2, it meets a comma followed directly by a closing bracket.
It stops with “Trailing comma is not allowed before ']'” at line 3, column 18, the 38th character of the document.
Removing that one comma makes the whole document valid; JavaScript code accepts a trailing comma, but JSON does not.
Questions
Why does my JSON fail when it looks fine?
Usually a trailing comma, single quotes, a comment or an unquoted key, which JavaScript allows and JSON does not. The validator shows the line and column of the first one it meets.
Will converting CSV to JSON change my numbers?
Not with safe typing: values such as phone numbers or codes with leading zeros stay text, and large numbers are not rounded. The preview shows how each column will be typed before you convert.
Why does YAML read no as false?
Older YAML 1.1 parsers treat yes, no, on and off as true and false. The YAML tools warn when a value would be read that way and suggest quoting it.
Can these tools open very large files?
The viewers are built for large files and open them in your browser without a server; the limit is your device’s memory, so a phone holds less than a computer.
Start with these
- CSV to SQL Converter Free preview: the column types found in your data and the first lines of the SQL (up to 20)
- JSON Formatter Pretty-print, minify and fix JSON with exact error locations.
- JSON Validator Strict JSON validation with exact error locations and every path listed.
- CSV to JSON Converter Two-way CSV ⇄ JSON with delimiter detection, safe typing and a preview table.
- XML Formatter Pretty-print or minify XML and find syntax errors by line and column.
- Localization File Translator Translate app language files and get them back in their own format, placeholders intact.
More tools here
- Comma Separated List Converter Column to comma list and back — or SQL IN, JSON, Python and CSV — in one paste.
- JSON Viewer & Tree Editor Browse, search and edit big JSON files in a fast tree — and copy any path.
- JSON ↔ YAML Converter Two-way JSON ⇄ YAML conversion that keeps numbers exact and warns about YAML traps.
- HTML / Web Table to CSV & Excel Paste a table from any web page, Word file or Wikipedia article — get clean CSV or Excel.
- YAML Validator & Formatter Find YAML errors by line, catch YAML 1.1 traps, check Compose and Actions files, format.
- Excel to JSON Converter Spreadsheet rows to clean, typed JSON — header row as keys, dates as ISO 8601.
- XML ↔ JSON Converter Two-way XML ⇄ JSON with control over attributes, arrays and namespaces — XXE-safe.
- JSON Schema Validator Check JSON against a schema and get every error with its path, line and a clear fix.
- JSON to Excel Converter API responses and nested JSON to a clean Excel workbook — one sheet per list.
- Table Converter Paste a table in any common format, tidy it in a grid and convert it to any of 29 formats.
- JSON Diff & Compare Structural JSON compare with JSON Patch and Merge Patch export — and apply patches too.
- TOML ↔ JSON Converter Exact TOML ⇄ JSON / YAML conversion, with errors that name the rule and the line.
Lessons on this
- Data Formats (JSON, YAML, TOML, XML, CSV), 48 lessons
- Groovy (Jenkins, Gradle and Spock), 13 lessons
- Python, 156 lessons
- MySQL & MariaDB in Depth, 32 lessons
- PL/SQL & T-SQL (Oracle and SQL Server), 51 lessons
- F#, 19 lessons
All 20: Lessons on this
- Go
- Git & GitHub
- SQL (PostgreSQL, MySQL, SQLite)
- Database Management Systems (DBMS)
- C# & .NET (C# 14, .NET 10 LTS)
- JavaScript (ES2026)
- Building Web Apps with Laravel
- GIS & Geospatial Data (QGIS, GeoPandas, PostGIS)
- Dart (3.13)
- Ruby on Rails
- Elixir & Erlang/OTP
- NestJS
- PHP (8.5)
- Web Scraping & Browser Automation (Python and JavaScript)
All 40 tools
Every tool here by name, grouped by what it is for.
Show the full listHide the full list: All 40 tools
JSON viewers, validators & repair
9 tools- JSON Diff & Compare Pro tool
- JSON Formatter Pro tool
- JSON Repair Tool Pro tool
- JSON Schema Generator Pro tool
- JSON Schema Validator Pro tool
- JSON Table Editor (View and Edit JSON Arrays as a Spreadsheet) Pro tool
- JSON Validator Pro tool
- JSON Viewer & Tree Editor Pro tool
- JSONPath & JMESPath Tester Pro tool
YAML, TOML & .env config files
5 toolsXML, XPath & XSD tools
4 toolsConvert & extract
13 tools- CSV to JSON Converter Pro tool
- Localization File Translator Pro tool
- Comma Separated List Converter Pro tool
- HTML / Web Table to CSV & Excel Pro tool
- CSV to SQL Converter Premium tool
- Excel to JSON Converter Pro tool
- JSON to Excel Converter Pro tool
- Table Converter Pro tool
- Prepare Documents for AI (PDF/Word to LLM-Ready Markdown) Pro tool
- GeoJSON Editor (Map, Validate, Fix & Convert) Pro tool
- SQL to CSV Converter Pro tool
- JSON Lines (JSONL / NDJSON) Converter Pro tool
- Text to PDF Converter Pro tool
Format & clean
1 toolCheck & analyze
3 toolsCreate & generate
3 toolsEncode & encrypt
1 toolLook up & learn
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Inside this hub
Good to know
- 37 of 40 tools run entirely in your browser; the other 3 explain on their pages what they send.
- 35 of 40 keep working without a connection once loaded.
What a pass opens here
35 Pro tools and 5 Premium tools here need a pass.
- Pro pass opens 35 of 40 ₹179 / $5.99 for 30 days
- Premium pass opens all 40 ₹799 / $19.99 for 30 days