Chunked File Packager
When an upload or transfer has a per-file size limit, choose a local file and a part size. This tool reads its real bytes, creates numbered parts and SHA-256 checksums, then packages them with a manifest in a ZIP. At the destination, supply that ZIP or the loose manifest and parts. The restorer uses the manifest order, checks every part and the whole file, and downloads the exact original bytes only after all checks pass.
Key features
- Split any local file type into numbered byte-exact parts of 0.5, 1, 2 or 4 MiB
- Download a ZIP package, a JSON manifest, or individual .part files
- Record SHA-256 of each part and the complete source file
- Restore from a ZIP or a manifest plus selected parts, regardless of selection order
- Reject missing, extra, duplicate, renamed, truncated or modified parts before download
How to use
- Choose a local file and a size for each part, then create the package.
- Review the part list and checksums; download the ZIP, or save the manifest and each part separately.
- To restore, select the package ZIP or select manifest.json and all of its .part files.
- Run restoration; the tool verifies each part and the whole file before offering the original bytes for download.
Use cases
- Send a file across a service with an individual attachment-size limit
- Copy numbered parts through different offline media and recombine them later
- Detect a missing or altered transfer part before opening the reconstructed file
- Keep a reproducible manifest of a test fixture split for teammates
Frequently asked questions
Can parts be selected in a different order?
Yes. The manifest fixes each numbered filename, offset, length and SHA-256. Selection order does not matter; swapping their filenames or bytes fails verification.
What happens if one part is missing or corrupted?
Restoration stops and names the missing or invalid part. It never offers a partial result as a verified file.
Is a SHA-256 match proof of who made the file?
No. Hashes detect changes relative to this manifest, but the manifest itself is not signed and does not authenticate its sender.
What file types and sizes work?
Any file type up to 24 MiB, with at most 48 parts. Choose a 0.5–4 MiB part size; this browser implementation keeps the generated package in memory.
Can I restore loose parts without the ZIP?
Yes. Download manifest.json and all numbered .part files. Select the manifest and parts in the restore panel; extra or repeated filenames are rejected.
Privacy
All bytes stay in this browser tab while they are split or restored. The tool does not upload, save to a server, or automatically overwrite the source. The manifest contains the original filename, sizes and hashes; inspect it before sharing.
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