YAML Lint: Check YAML for Errors Lint YAML online and see the exact line of a wrong indent or a tab. Free, private, no signup.
Quick answer: Validate, beautify and clean JSON, CSV, XML and YAML.
Related: Data Formatter: JSON, CSV, XML and YAML · JSON Formatter and Validator · CSV Formatter and Cleaner · XML Formatter and Validator · File Format Guides and Free Tools
How to use the YAML Lint: Check YAML for Errors Validate, beautify and clean JSON, CSV, XML and YAML.
The Data Formatter checks and tidies JSON, CSV, XML and YAML. It shows the exact line and column of an error, can fix common JSON mistakes, and cleans CSV by trimming spaces, removing empty rows and columns and dropping duplicates. Developers use it to read API responses, analysts to prepare files before an import. The result can be copied or downloaded, and your text never leaves your device.
Paste or upload your data Choose the options Copy or download the result Tips After valid JSON, use Edit as a table or Convert to CSV or Excel to carry on in another tool. Invalid JSON shows the exact line and column. “Auto-fix” repairs comments, trailing commas and single quotes. Numbers and key order are kept exactly as written – nothing is rounded. CSV: any delimiter is detected automatically; pick the one you want for the output. YAML: comments are kept, and you can convert YAML → JSON or paste JSON to get YAML. Example Input: name: demo
ports: 80
Output: Error at line 2: tabs are not allowed
Browse by topic Who uses Data Utility Frequently asked questions · Data format benchmark
Frequently asked questions What does YAML lint check? That the YAML is valid, and it shows the line of the first error.
What can the Data Formatter do? Validate, beautify, minify and clean JSON, CSV, XML and YAML. Errors show the exact line and column, and JSON can be auto-fixed for common mistakes such as trailing commas and single quotes.
Related pages Data Formatter: JSON, CSV, XML and YAML : Validate, beautify and clean JSON, CSV, XML and YAML for free. Highlight columns, rows and words and download as Excel. Runs in your browser.JSON Formatter and Validator : Beautify, minify and validate JSON online for free. It shows the exact line of an error and can auto-fix common mistakes. Runs in your browser.CSV Formatter and Cleaner : Clean a CSV online for free: trim spaces, drop empty or duplicate rows, change the delimiter and tidy headers. Runs in your browser.XML Formatter and Validator : Beautify, minify and validate XML online for free. It shows the line and column of any error so you can fix it fast. Runs in your browser.YAML Formatter and Validator : Format and validate YAML online for free, or convert YAML to JSON in one click. Errors show the exact line. Runs in your browser, no upload.JSON Validator Online : Validate JSON online and see the exact line and column of any error. Auto-fix comments, trailing commas and single quotes. Free, in your browser.JSON Minifier : Minify JSON online to remove spaces and line breaks and make the file smaller. Free, runs in your browser, nothing is uploaded.XML Validator Online : Check if your XML is well-formed and find the exact line and column of the first error. Free, in your browser, nothing is uploaded.Topic guides Guides More free tools JSON, CSV, Parquet and Excel Converter JSON to CSV Converter CSV to JSON Converter CSV to Parquet Converter JSON to Parquet Converter Parquet to CSV Converter Parquet to JSON Converter CSV to Excel Converter JSON to Excel Converter Excel to CSV Converter Excel to JSON Converter Data Formatter: JSON, CSV, XML and YAML JSON Formatter and Validator CSV Formatter and Cleaner XML Formatter and Validator YAML Formatter and Validator JSON Validator Online JSON Minifier XML Validator Online YAML to JSON Converter Remove Duplicates from CSV CSV to SQL Converter Excel to SQL Converter Mask Emails in a CSV File Compare Two CSV Files CSV Data Quality Checker JSON Beautifier XML Beautifier YAML Validator Online CSV Delimiter Converter Compare Two Excel Files CSV Diff Tool JSON to SQL Converter SQL INSERT Statement Generator Anonymize CSV Data Mask PII in Excel Files Fake Data Generator Test Data Generator TSV to CSV Converter Semicolon CSV to Comma CSV Check a CSV for Duplicates and Blanks CSV Data Profiler Gzip Compress Files Online Compress a CSV File Online Compress a JSON File Online Reduce File Size Online Open a .gz File Online Open .gz Files Online (Gunzip) Image to Excel Converter (OCR) Image to CSV Converter (OCR) Chat with Your CSV File Chat with Your Excel File Generate Data from CREATE TABLE JSON Schema Data Generator File Compressor: Gzip JSON, CSV, XML, YAML, Parquet Screenshot to Table Converter (OCR) SQL INSERT Generator from CSV, JSON, Excel or Parquet Schema-Based Data Generator (JSON Schema) Mock Data Generator Data Profiler Data Comparison (CSV and Excel Diff) Chat with Your Data Data Dictionary Generator Dataset README Generator Free Data Lineage Tool: Transform Data and Download the Lineage API Response to Table: JSON API to CSV JSON API Response to CSV Document Database Columns with AI Generate SQL Column Comments README for a CSV Dataset Dataset Documentation Generator Delete Columns from a CSV File Reorder Columns in a CSV File Remove Empty Rows and Columns from CSV Find and Replace in a CSV File Change Date Format in a CSV File Convert Excel Date Numbers to Dates File Size Calculator: CSV, JSON, Excel, Parquet Merge or Split Files: CSV, JSON, Excel, Parquet Combine Multiple CSV Files into One Merge Parquet Files into One Split a CSV File into Parts Split a Large CSV into Smaller Files Split a Parquet File into Parts Text to Table: Paste Text, Get a Table Paste Text into a Table for Excel Convert Text to CSV Markdown Table to CSV Copy a PDF Table into Excel Screenshot to CSV Screenshot to Excel Picture to Excel Photo of a Table to Data PNG to Excel Converter JPG to Excel PNG to CSV OCR Table to Excel Convert Many Images to Excel Batch Screenshot to CSV Offline CSV Converter (Desktop App) CSV Converter Desktop App Extract a Table from an Image Table Image to CSV Screenshot to Google Sheets PDF Table Screenshot to Excel Generate Test Data from Production Data Anonymize CSV Data for Testing GDPR-Safe Test Data Generator Open a Large CSV File Online Convert a Large CSV to Parquet Query a Large CSV with SQL Split a Large JSON or NDJSON File JSON Table Editor: Edit Nested JSON as a Table JSON Visual Editor Online Edit JSON as a Table JSON Array to Editable Table SQL on Your Files: Query CSV, Excel and Parquet Query a CSV File with SQL Run SQL on an Excel File Query Parquet Files Online Join CSV Files with SQL DuckDB in Your Browser Synthetic Data Generator: Realistic Data From Your File Generate Synthetic Data from a CSV Privacy-Safe Test Data from Real Data Synthetic Dataset from an Excel File Data Transformation: Join, Trim, Concatenate Join Two CSV Files on a Key Merge CSV Files by a Common Column VLOOKUP Alternative for CSV and Excel Files Join Two Excel Files on a Key Column Concatenate Columns in a CSV File Trim Spaces in a CSV File Split a CSV Column into Two or More Filter CSV Rows Online Combine First and Last Name Columns Free Data Lineage Tool Data Lineage Report as HTML Share Your Data Together with Its Lineage Data Audit Trail for CSV and Excel Files Data Provenance Tool for Files Parquet to Excel Converter Excel to Parquet Converter Parquet Viewer Online CSV Viewer Online Flatten Nested JSON to CSV Open a Parquet File Without Python Ask Questions to a CSV File with AI Talk to Your Data: Free AI Data Chat Chat with a JSON File Chat with a Parquet File Free AI Data Analysis Tool Analyze a CSV with AI AI Data Dictionary Generator Data Dictionary from a CSV File Write Column Descriptions with AI README Generator for a Dataset README for a GitHub Dataset Mask Phone Numbers in a CSV Mask Credit Card Numbers in a File Mask Names in a CSV File Hash Columns in a CSV File Pseudonymize Data Online Mask Sensitive Data in JSON Data Masking for Test Environments Anonymize an Excel File Free Data Anonymization Tool PII Detection Tool for CSV and Excel Mask Data Before Sharing GDPR Data Anonymization for Files AI Data Generator That Learns From Your File Synthetic Test Data Generator Synthetic Data for Machine Learning Generate Fake Customer Data Synthetic Data vs Masked Data What Is Data Lineage? Track It Free Data Lineage for Excel Files Data Lineage for JSON Files Data Lineage Example Data Lineage for GDPR and Audits Data Dictionary Maker How to Chat with a CSV File Data Profiler Online Fake Database for Testing XLS to CSV Converter XLSX to CSV Converter Online Excel to CSV Converter Convert JSON to a Spreadsheet Connect Excel to JSON Export CSV to JSON CSV to JSON Converter: Typed Values, Large Files JSON Parser Online XML Pretty Print Format XML Online Format YAML Online YAML Lint: Check YAML for Errors Format CSV Online JSON Pretty Print Format JSON Online JSON Lint: Check JSON for Errors Fix Invalid JSON Online JSON Syntax Checker Sort JSON Keys Alphabetically CSV Validator Online Clean a CSV Online JSON Viewer Online Edit JSON Online View JSON as a Table JSON to Table Online Edit Nested JSON Data Lineage for Parquet Files Data Lineage for CSV Files Data Lineage Tool: Track Every Change to a File Track Changes Made to a Data File Free Column-Level Data Lineage Tool Free Column Lineage Tool What Is Column-Level Lineage? Column-Level Lineage for CSV Files How to Trace a CSV Column to Its Source Column Lineage Example How to Check Personal Data Was Masked SQL Column Lineage for Your Files Data Masking and Anonymization About Data Utility: Free Online Data Tools Privacy Policy Blog & Guides How to Convert JSON, CSV, Parquet and Excel Files Online How to Convert JSON to CSV in 4 Steps (Free, Private) How to Convert CSV to JSON in 4 Steps (Free, Private) How to Convert CSV to Parquet in 4 Steps (Free, Private) How to Convert JSON to Parquet in 4 Steps (Free, Private) How to Convert Parquet to CSV in 4 Steps (Free, Private) How to Convert Parquet to JSON in 4 Steps (Free, Private) How to Convert CSV to Excel in 4 Steps (Free, Private) How to Convert JSON to Excel in 4 Steps (Free, Private) How to Convert Excel to CSV in 4 Steps (Free, Private) How to Convert Excel to JSON in 4 Steps (Free, Private) Data Formatter: Fix and Format JSON, CSV, XML and YAML JSON Formatter and Validator: Fix Broken JSON Online How to Clean a CSV File Online: Remove Duplicates and Empty Rows XML Formatter and Validator: Beautify and Check XML YAML Formatter and Validator: Check and Fix YAML Screenshot to Table: Image to Excel, CSV or Parquet (OCR) SQL INSERT Generator: Turn CSV, Excel or Parquet into SQL Free Mock Data Generator: Realistic Test Data in 1 Minute Data Profiler: Check Data Quality Before You Use It Compare Two CSV or Excel Files: Find Added, Removed and Changed Rows Data Masking: Hide Emails, Phones and Names Before Sharing Chat with Your Data: CSV, Excel, JSON and Parquet (Free AI) Data Dictionary Generator: CREATE TABLE with AI Descriptions Dataset README Generator: Explain Your Data with AI Password-Protected Data Reports: Share a Locked HTML File How to Compress JSON, CSV, XML, YAML and Parquet Files Generate Test Data from a CREATE TABLE (500k Rows) CSV vs JSON vs Parquet vs Excel: Differences and Which to Use How to Open a Parquet File: 3 Free Ways (No Python Needed) Free Data Lineage Tool: Share Your Result with Its Lineage Column-Level Data Lineage: Follow Every Column, Free Tool Data Lineage: See Which Tool Changed Your File Data Transformation: Join, Trim and Concatenate Files Online VLOOKUP Alternative: Join Two CSV or Excel Files Online How to Concatenate Columns in a CSV (First and Last Name) How to Turn an API Response into a CSV (With a Bearer Token) How to Flatten Nested JSON From an API Into Columns CSV vs Parquet: File Size Test With 100,000 Rows Convert CSV to Parquet: pandas, DuckDB or Your Browser What Is Parquet? The Columnar File Format Explained CSV to JSON, Excel or Parquet: Size and Speed Test How Much Does Gzip Shrink CSV, JSON, Parquet and Excel? How to Fix Mixed Date Formats in a CSV (With Examples) Turn a Public API into a Table: A Worked Example CSV vs JSON: Which One Should You Use? JSON vs Parquet: Which Format Should You Choose? Excel vs CSV: Which Should You Use for Data? VLOOKUP vs Join: Which Is Better for Combining Files? How to Merge Many CSV Files into One File How to Split a Large CSV File into Smaller Files How to Copy a Table from a PDF or Web Page into Excel Synthetic Data vs Random Fake Data: What Is the Difference? How to Generate Synthetic Data From a CSV, Step by Step How to Convert Many Screenshots to Excel or CSV at Once How to Run SQL on CSV, Excel and Parquet Files in Your Browser Reuse an Edited File in Another Tool: Recent Files Synthetic Data Without Python: Online Alternative to SDV How to Check the Quality of Synthetic Data (Checklist) Test Data Without Production Data: 3 Safe Ways Data Format Benchmark: CSV, JSON, Excel and Parquet Parquet Guides and Free Parquet Tools CSV Guides and Free CSV Tools JSON Guides and Free JSON Tools Excel Guides and Free Excel Tools Data Privacy Guides and Free Tools Test Data Guides and Free Generators Data Cleaning Guides and Free Tools AI Data Tools and Guides Extract Data from Screenshots and APIs Data Lineage and Audit Trail Guides File Format Guides and Free Tools Free Data Tools for Marketing Lists Free Data Tools for Finance and Accounting Exports Free Data Tools for Developers Free Data Tools for Data Analysts Free Data Tools for Small Business Frequently Asked Questions