About JSON ↔ CSV
Convert an array of JSON objects into a CSV with nested fields flattened into dot-notation columns, or turn CSV back into typed JSON with nesting restored. Preview the table and download the result. Everything happens locally in your browser: nothing is uploaded, stored, or logged. This focused JSON ↔ CSV page is designed for developers and analysts moving API data into spreadsheets or loading spreadsheet exports into JSON-based tools. It opens directly to the working tool, rather than hiding the function inside a general converter or account dashboard.
The source is evaluated by a purpose-built parser or browser API in the current tab; it is not submitted to a remote formatter, compiler, or logging service. Your filename and file contents stay on the device. There is no upload queue, temporary cloud copy, account record, or server-side conversion job to delete later. That makes the tool practical for personal records, work material, and drafts that should not be handed to an unknown processing service.
The important limitation is straightforward: Arrays inside objects are kept as JSON text in a single cell. Number, true/false, and empty values are typed when converting CSV to JSON. Knowing that boundary helps you choose the right source file and check the result before relying on it. Processing speed and maximum size depend on your browser and available device memory, which is the honest trade-off for doing the work locally.
FileForge charges nothing for this tool and does not add a watermark. Once the page and its processing engine have loaded, the operation can continue without sending the file over the network. Use the numbered steps below, download the result, and review it before replacing an original file.