Compare Two CSV or XLSX Files
Compare two spreadsheet files using a selected key and group records into matched, missing, duplicate and conflicting buckets.
CSV
Merge Two CSV or XLSX Files by Column Name
Append two CSV, TSV or XLSX datasets and align their fields by header name in a downloadable CSV export.
Processing boundary: text and files are handled only for this request. Original files are not overwritten. Generated CSV downloads use expiring private tokens.
What this tool does
This merge tool appends the rows from two datasets and builds a union of their column headers. When one file contains a field that the other file does not, ReconNimble leaves that field blank rather than shifting values into the wrong column. The workflow is useful for monthly exports, regional lists, vendor files and historical datasets that share most—but not necessarily all—of their schema. Processing occurs within the current PHP request, the uploaded temporary files are not copied into public storage and the generated CSV is available through an expiring private token.
How to use it
- Select the first and second CSV, TSV or XLSX file.
- Run the merge and review row and column counts.
- Inspect the preview and download the generated UTF-8 CSV.
Limitations and review points
This operation appends rows; it does not match or consolidate records with the same key. Very large files are rejected according to the configured row and upload limits.
Frequently asked questions
What happens when headers differ?
The result contains the union of both header sets and leaves unavailable values blank.
Does it overwrite either source file?
No. ReconNimble creates a separate CSV export.
Can it merge more than two files?
Delivery 1 accepts two files per operation. Multi-way workflows are planned for Delivery 2.
Related spreadsheet tools
Smart Schema Mapper
Suggest column mappings between two files using normalized header names, business synonyms and sampled data types.
Spreadsheet Column Profiler
Profile column types, blanks, uniqueness, maximum text length and sample values before mapping or importing a dataset.