FREE TOOLS
CSV Table Joiner
Join two CSV tables by explicit keys with duplicate and unmatched-row policies.
Left CSV, Left CSV file (optional,takes precedence), Right CSV, Right CSV file (optional,takes precedence), Left delimiter, Right delimiter, Left key names JSON, Right key names JSON, Join kind, Duplicate key policy, Output delimiter, Protect spreadsheet formula expressions
CSV, JSON
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter the displayed example values,or choose the local input files requested by the controls. Optional source files take precedence where labelled.
- Choose Join tables and inspect the complete result and any reported limitations.
- Use Download result and each companion download link to save complete outputs. Reset clears output and restores example controls.
Examples
Left CSV: id,name
1,Ada
2,Ben
Right CSV: id,score
1,9
3,7
Left delimiter: ,
Right delimiter: ,
Left key names JSON: ["id"]
Right key names JSON: ["id"]
Join kind: inner
Duplicate key policy: cartesian
Output delimiter: ,
Protect spreadsheet formula expressions: true
Limitations
- Join two actual CSV tables by explicit equal-length key-column lists. Choose inner,left,full or left anti join. Exact string tuple keys;empty strings match and numeric-looking identifiers remain strings. Choose Cartesian duplicate multiplicity or reject duplicate keys. Output prefixes every column with left. or right.;anti output contains left columns only. Stable left/right row order,and full joins append unmatched right rows. CSV pads absent rows with empty cells;the complete JSON companion identifies every original row address. Default-on shared formula protection applies to all output cells. CSV cannot declare cell types. Projected output is admitted before expansion:50,000 rows,500 columns and500,000 cells including headers. Each source:1 MiB UTF-8,10,000 data rows,100 columns and100,000 cells including headers. Header-only tables are valid. Complete output budget20 MiB. All processing stays in your browser.
- Complete outputs only. Unsupported or oversized input is refused. Follow the displayed job-specific bounds and format policies.