dropslice
Open NWB, HDF5, MATLAB, NumPy and Zarr files in your browser. Browse what's inside, plot it, page through it. Nothing is uploaded.
Drop a file or a .zarr folder here
.nwb · .h5 · .hdf5 · .mat · .npy · .npz · .zarr
free · open source · reads files on your computer · no uploads, no cookies
What it opens
- NWB and HDF5: any size, read lazily, with compressed data (gzip, Blosc, Zstandard, LZ4, LZF and more).
- MATLAB .mat: v5 (the default) and v7.3, with structs, cells, text, logicals and complex numbers.
- NumPy .npy and .npz: integers, floats, complex numbers, booleans and text, in both memory orders. Pickled objects are never loaded.
- Zarr v2 and v3: drop the folder, or open a public store with
?url=. - Views: line plots, heatmaps, RGB images, tables and slicing through any dimension, by h5web.
Questions
How do I open an NWB file without installing anything?
Drop it on dropslice. It reads the file in your browser and shows its groups, datasets and attributes, with line plots, heatmaps and tables. Large files are read lazily, so a multi-gigabyte recording opens in seconds.
Can I open a MATLAB .mat file without MATLAB?
Yes. dropslice opens MATLAB v5 .mat files (what save writes by default) and v7.3 files, which are HDF5: numbers, text, logicals, structs, cell arrays and complex numbers, in MATLAB's own dimensions.
How do I look inside a NumPy .npy or .npz file?
Drop it on dropslice to see its shape, type and values as a plot, image or table. Object arrays are refused rather than unpickled, because unpickling can run code.
Are my files uploaded?
No. dropslice is a static page; files are read by your browser on your computer and never sent anywhere. The page has no server, no cookies and no tracking.
How do I open a Zarr store?
Drop the .zarr folder on the page, or choose it with Open a Zarr folder. Zarr v2 and v3 both work. A public Zarr store with consolidated metadata can also be opened by web address with ?url=.