JSON to CSV

Who typically uses it?

• Developers exporting API responses to a spreadsheet.
• Analysts doing quick checks in Excel/Sheets before deeper modeling.
• Ops teams preparing import files for CRM, ticketing, or data warehouses.

Worked example (header detection)

Suppose your API returns two records:

[
  { "id": 1, "name": "Ada" },
  { "id": 2, "name": "Linus", "team": "Kernel" }
]

The tool builds the header set $H$ from all keys, so: $H = \{\texttt{id},\texttt{name},\texttt{team}\}$and $|H|=3$ columns are produced.

A typical CSV output will look like:

id,name,team
1,Ada,
2,Linus,Kernel

Notice how the first row has an empty value for $\texttt{team}$. That’s expected when a key is missing in some objects.

1) Exporting API data to a spreadsheet

Background: You fetched a list of issues from an API and want a quick pivot table in Sheets.

Input JSON (simplified):

[
  { "id": 101, "status": "open", "assignee": "Sam" },
  { "id": 102, "status": "closed", "assignee": "Alex" }
]

Result: a CSV table with $|H|=3$ columns. You can paste it directly into Sheets.

Tip: if the API returns YAML in logs, convert it first using our YAML to JSON converter.

2) Creating an import file (CRM / ticketing)

Background: Your tool accepts CSV imports, but your source data is JSON.

Example input:

[
  { "email": "[email protected]", "plan": "Pro" },
  { "email": "[email protected]", "plan": "Free" }
]

Result CSV gives you two columns. In symbols: $H=\{\texttt{email},\texttt{plan}\}$.

How to apply it: save as $\texttt{users.csv}$ and import.

3) Sanitizing and sharing a non-sensitive sample

Background: You want to share a minimal reproduction with teammates. Convert to CSV so it’s easy to read and compare.

Input values are small by design; if you share a URL with results, remember the query-string limit. If you need safer sharing, share a file instead.

Keep your JSON “row-like”

CSV works best when each object represents one row and each key is a column. If you have nested objects, convert/flatten them before exporting.

Watch out for commas and line breaks

Values containing commas are quoted in the output. Line breaks are escaped as $\\n$ and $\\r$, which avoids breaking rows in most spreadsheet pastes.

Convert first, then export

If your source is XML or YAML, convert it to JSON first with XML to JSON or YAML to JSON, then paste it here for CSV output.

Header detection

The converter builds the header set by taking the union of keys across all objects:

The number of columns is simply $|H|$.

Row construction

For each object $o_i$ and each header $h\in H$, the cell value is: $v_{i,h}=o_i[h]$.

Missing keys produce empty cells. A JSON $\texttt{null}$ becomes the text $\texttt{null}$ in CSV.

CSV is a format, not a schema

CSV doesn’t tell you column types; everything looks like text at first. If you need strict typing, store the original JSON as well.

JSON5 parsing

The parser is forgiving (comments and trailing commas may work), which is handy when you copy from logs or config-like JSON.

Not a full CSV spec implementation

CSV has edge cases (different delimiters, embedded quotes, Excel quirks). This tool targets the common “copy/paste” workflow.

Nested or relational data may not fit

If your JSON contains arrays-in-arrays or nested objects, a single table may be the wrong representation. Consider exporting multiple tables or using a database.

External references

• RFC 4180 (CSV format guidance): rfc-editor.org/rfc/rfc4180
• JSON5 (relaxed JSON parsing): json5.org