Data Engineering & Processing Tools
Browser-based tools for converting, validating, transforming, and cleaning data across CSV, JSON, XML, Excel, and SQL formats. All processing runs locally — no file uploads, no external services, no data leaves your device.
31 tools covering CSV processing, JSON transformation, Excel conversion, XML validation, and SQL formatting.
Working with Data Formats in Practice
Most data engineering work is not algorithm design — it is format wrangling. A stakeholder sends an Excel file when your pipeline expects JSON. An API returns XML when your datastore speaks CSV. A CSV export from a third-party tool uses inconsistent column names, mixed date formats, and duplicate rows. These are not edge cases; they are the daily reality of working with data across system boundaries.
The tools on this page handle the mechanical parts: converting between formats, validating structure, stripping nulls, deduplicating rows, merging files, and reformatting queries. They run entirely in your browser, so you can process sensitive production data without routing it through a third-party service.
CSV Processing and Cleaning
CSV is ubiquitous precisely because it is simple — but that simplicity hides real complexity. Delimiter conflicts (commas in addresses or prices), inconsistent quoting, mixed line endings, null representations (NULL, N/A, \N, empty strings), and duplicate rows are all common issues that break downstream pipelines silently.
Common CSV workflows: validate structure and delimiter before ingestion; extract or rename columns to match a target schema; filter rows by a column condition to create a subset; split large files into chunks for parallel processing; deduplicate on a key column before loading into a database; handle null values by replacing or dropping; convert to JSON or SQL INSERT statements for seeding development databases or test fixtures.
JSON, XML, and Format Conversion
JSON is the lingua franca of modern web APIs. The JSON Formatter validates syntax and reformats with consistent indentation — useful for reading minified API responses. JSON Diff shows structural differences between two payloads, which saves time when debugging webhook deliveries or comparing configuration versions. JSON Flattener normalises nested objects into flat key-value pairs before loading into a spreadsheet or columnar store.
XML remains common in enterprise integrations, SOAP services, and document formats (OOXML, SVG, XHTML). The XML Validator checks well-formedness and reports parsing errors with line numbers. The XPath Validator lets you test node selection queries against a live document — useful when building data extraction pipelines or writing XSLT stylesheets. Conversion tools handle the XML ↔ JSON and XML ↔ CSV bridges that come up constantly in ETL work.
Excel, ETL Prep, and SQL
Excel files are a fact of life for data engineers: analysts export from business intelligence tools, finance teams share forecasts, and clients deliver data in .xlsx regardless of what your pipeline expects. The Excel tools use SheetJS to read workbooks entirely in the browser, convert sheets to CSV or JSON, merge multiple sheets, and clean common formatting issues (leading/trailing spaces, inconsistent casing, stray characters).
The CSV to SQL Insert converter generates INSERT INTO statements directly from a CSV, which accelerates seeding development databases and creating test fixtures without writing manual SQL. The SQL Formatter prettifies query strings for readability before committing to version control — consistent formatting makes query diffs meaningful and reduces review noise.
Data Tools
All tools run entirely in your browser. No data is sent to any server.
CSV Tools
Parse, filter, transform, and convert CSV files without writing a script. All operations run in your browser on the raw text.
JSON Tools
Format, compare, flatten, and convert JSON data. Useful for inspecting API responses, debugging nested structures, and preparing data for downstream tools.
Excel Tools
Convert, merge, and clean Excel spreadsheets entirely in your browser using SheetJS — no file upload or server processing required.
XML & TSV Tools
Validate XML documents, query nodes with XPath, and convert between XML, TSV, and CSV formats.
SQL Tools
Format and prettify SQL queries for readability before committing to version control or sharing with your team.
Data Guides — Coming Next
In-depth guides on CSV vs TSV, JSON vs XML, Excel data cleaning strategies, and ETL pipeline best practices are in progress.
Browse all guides →Frequently Asked Questions
What's the difference between CSV and TSV?
Both are plain-text tabular formats. CSV (Comma-Separated Values) uses commas as the field delimiter. TSV (Tab-Separated Values) uses tab characters. TSV is less likely to conflict with data that contains commas — addresses, descriptions, and financial figures frequently include commas, which require CSV quoting rules to handle correctly. When in doubt, prefer TSV for data that may contain free-text fields.
How do I validate JSON in the browser?
Paste your JSON into the JSON Formatter tool — it parses the input and highlights any syntax errors with the line and character position. Valid JSON is reformatted with consistent indentation. Common errors include trailing commas (not permitted in JSON), single-quoted strings (JSON requires double quotes), and unquoted keys.
When should I use JSON vs XML?
JSON is the default choice for web APIs and configuration files — it is lighter, maps directly to JavaScript objects, and is human-readable without verbosity. XML is better when you need document-centric data with mixed content (text interspersed with markup), namespace support, or schema validation via XSD. XML is also common in enterprise integrations (SOAP, BPEL) and document formats (OOXML, SVG). For new projects with no legacy constraints, JSON is almost always the right choice.
Is all processing done in my browser?
Yes. Every tool on this page operates on data you paste or upload directly in your browser. No file contents are sent to any server — transformations, validations, and conversions run entirely via JavaScript and WebAssembly in your local tab. This means you can safely process sensitive datasets, production credentials embedded in configs, or confidential business records without exposing them to a third-party service.
How do I convert Excel to CSV without losing data?
Use the Excel to CSV Converter. It reads your .xlsx or .xls file using SheetJS, preserves cell values and number formatting, and outputs standard CSV. One thing to watch: Excel stores dates as serial numbers internally; the converter maps these to ISO 8601 date strings by default. Multi-sheet workbooks export one sheet at a time — use the sheet selector to pick the one you need.
What is JSON flattening and when do I need it?
Flattening converts a deeply nested JSON structure into a single-level object by joining key names with a separator (e.g., address.city → "address_city"). This is useful before importing JSON into a spreadsheet or relational database that cannot handle nested structures natively. It is also commonly used to prepare API responses for CSV export or to feed data into tools that expect flat key-value pairs.
Can I merge multiple CSV files at once?
Yes — the CSV Merger tool accepts multiple files, aligns them by header columns, and concatenates rows into a single output. If the files have different column sets, you can choose to include all columns (filling missing values with empty strings) or intersect on common columns only. This is useful for combining monthly export files, aggregating data from multiple sources, or reuniting a CSV that was split for batch processing.