Choose columns, their order and their names. Keep records as they are.
Prepare a smaller export with explicit headers. Every data record stays in its original order, including repeats. Selected cells stay exact strings in preview and raw JSON.
Input: UTF-8 CSV/TSV, 2 MiB, 20,000 data records, 100 columns, 200,000 total cells including header. Strict first error blocks all partial output. Header-only input is valid. File selection replaces pasted text even when rejected.
Choose output columns
Each source once; arrange deliberately. Output names are exact nonblank strings and must be distinct. Case and spaces matter. Matching an unselected original header is allowed. No automatic suffixes.
Ready for an export.
Prepared result
Preview shows at most 100 rows. Source records count header as 1; quoted multiline cells remain one record. JSON mapping indices are zero-based.
Literal CSV may be interpreted as formulas by spreadsheets. Prefix mode adds apostrophes to formula/control-leading headers and cells, changes literal values and is not universal spreadsheet safety. Raw JSON remains unchanged.
Worked example
Select internal_note, order_id, amount_text in that order; name them comment, reference, amount_text. Three original records remain three, including the repeated 00123 order. Quoted notes contain commas and a newline. 00007 and 010.50 retain their exact spelling. Output has 12 cells including header; literal CSV 169 bytes, prefixed CSV 171 bytes and two prefixed cells.
Limits and data handling
CSV is fully quoted comma output with CRLF and final newline. Its inclusive 2 MiB budget includes headers, escaping and potential prefixes. Raw canonical JSON has a separate inclusive 16 MiB full-envelope cap. A blocked export leaves the other available if its own budget passes. No sorting, deduplication, trimming, numerical conversion, repair or import certification.
Your file is processed in this browser without uploads, analytics or browser storage. A host serves static assets. Downloads create new files; originals stay unchanged. Clear removes displayed values; saved downloads remain. This preview has remaining device and accessibility checks.