2026-05-31 · 1 min read
From CSV to JSON: watch headers and types
Headers become keys—normalize names before converting at scale.
Key takeaways
- Decide whether the first row is headers before conversion.
- Numbers may arrive as strings—validate downstream.
Headers and blanks
Confirm delimiter and header row expectations—Excel exports vary by locale.
Watch blank cells—they often become null or empty strings depending on parser settings.
After JSON emerges
Pretty-print JSON Formatter output for review, then validate if this JSON feeds production systems.
BOM and numeric IDs
Excel UTF-8 CSV often starts with a BOM that becomes the first header (`\ufeffid`). Strip BOM before mapping or the API will reject unknown keys.
Keep SKUs and ZIP codes as strings. Auto-number conversion drops leading zeros that checkout systems still require.
FAQ
Why do numbers look like strings?
CSV is untyped text; JSON conversion preserves strings unless you coerce elsewhere.
Are CSV uploads server processed?
Yes—file tools send data to the server for conversion.