How to open a JSON file online
Three steps, a few seconds, no software.
Open your .ARFF file
Drop it on the box, choose it from your device, or paste the data straight in.
View the structure
Your .ARFF file opens as a tidy, foldable tree, with the exact line of any error pointed out.
Search, copy or download
Search keys and values, copy any path or value, switch to a table, or download a clean copy.
What is a .ARFF file?
The most common data format on the web.
An ARFF file is a plain-text dataset format used by the Weka machine learning toolkit. Open it in Weka Explorer, any text editor, or load it in Python with scipy.io.arff. To convert to CSV, use Weka's Preprocess tab or strip the header lines manually - the data section is already comma-separated.
Programs that open .ARFF files
| Full name | Attribute-Relation File Format |
|---|---|
| Developer | University of Waikato (Machine Learning Group) |
| First released | 1993 (Weka project, University of Waikato) |
| Category | Text & Code |
| MIME type | text/plain |
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Frequently asked questions
Is my .ARFF file uploaded anywhere?
No. The file is opened directly from the copy you pick.
My .ARFF file is invalid. Can you fix it?
We show the exact line and column of the first error. For common problems like comments, trailing commas, single quotes or Python-style True/False/None, click Try to repair and download the fixed file.
How large can the file be?
Up to 50 MB. The tree only builds the branches you open, so even multi-megabyte files stay responsive.
What is JSONPath?
A path like $.orders[3].customer.email that points to one value inside the data. Click any node to see its path and copy it for code, jq or your API docs.
Can I see my data as a table?
Yes. Any array of objects can be shown in the Table view and downloaded as CSV.
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