CSV to JSON: Convert Rows into Data Objects — Practical Guide
Convert CSV to JSON by selecting a delimiter, using a header row, and preserving quoted fields and identifier columns as text. Read the steps and example.
CSV conversion turns rows and columns into JSON values, usually an array of objects. The first row often supplies property names, but CSV files do not have a single universally enforced schema. Delimiters, quoting, line endings, and character encoding can differ by exporter. Choose the correct parsing options, protect identifiers such as postal codes from automatic number conversion, and inspect the output before using it in an API or database.
Prepare headers and consistent rows
Use one header row with a unique, non-empty name for each column. Make sure data rows contain the expected number of cells. Remove titles, subtotals, and blank separator lines unless they are part of the dataset. Select comma, tab, or semicolon according to the actual file content; a .csv extension does not prove that commas separate the fields. Confirm the text encoding if accented characters appear corrupted.
Respect quotes and keep identifiers as strings
A quoted CSV field may contain a delimiter, quote mark, or newline. Use a standards-aware parser rather than splitting each line on commas. Decide whether values should remain strings or be converted to numbers, booleans, and null. Postal codes, phone numbers, and long IDs usually should stay strings because leading zeros and exact digits matter. Do not let a spreadsheet silently reformat those values before conversion.
Check the generated objects
Compare the number of output objects with the number of data rows and inspect records with empty cells, quotes, and multiline text. Empty cells can become empty strings, null values, or omitted properties depending on the converter. Write down the chosen mapping if another system will import the output. For sensitive records, use a local processing tool and avoid saving data to untrusted shared storage.
Worked example
CSV:
name,postal_code
Ada,00123
JSON:
[{"name":"Ada","postal_code":"00123"}]Why does CSV data sometimes shift into the wrong columns?
A field may contain a comma or newline that must be quoted correctly, or the selected delimiter may not match the source file.
Reference and further reading
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