Rename CSV headers in bulk with old:new mapping — standardize client exports fast. Fix 40 messy columns before import — local parsing, free, no signup.
Content reviewed October 2026 · About Toolzum
Extract CSV columns by name into clean lists. Pull email and name columns from pasted CSV in seconds — local parsing, free, no signup.
Validate CSV structure — flag rows with wrong column counts and empty cells before import. Catch bad rows locally — free, no signup.
Merge two CSV files on a shared key column — join related exports into one sheet. Combine two tables without spreadsheets — local merging, free, no signup.
Turn messy client CSV and Excel sheets into clean JSON arrays or keyed objects with column mapping. Developers convert 50 exports without hand-editing — local SheetJS work, 2 free batches a day.
Clean messy CSVs — trim whitespace, fix encodings, deduplicate rows, standardize blanks. Make client exports analysis-ready — local processing, free, no signup.
Enter comma-separated old:new pairs (name:full_name, role:job_title) — headers rename in one pass. Unmapped columns keep original names, so partial maps are safe.
Duplicates are not flagged — mapping two columns to the same new name produces two identical headers. Rename or drop one side first.
No — only header row rewrites; all rows pass through byte-identical. Verify with a diff on the first run.
No — parsing runs locally in your browser. Data never leaves your device.
No — mappings split on colons and keep only the first two parts, so a mapping like time:12:30 renames the header to 12, dropping the rest. Unmatched headers pass through unchanged, so partial maps are safe.
Column Extractor
Extract CSV columns by name into clean lists. Pull email and name columns from pasted CSV in seconds — local parsing, free, no signup.
Data Type Converter
Convert values between string, number, boolean, array, and object types with validation. Fix API type mismatches fast — local conversion, free, no signup.
Data Format Converter
Convert data between JSON, CSV, XML, YAML, and TSV with structure preserved. Migrate configs across stacks without rewriting — local PapaParse/xml2js/yaml parsing, free, no signup.