File Size Limits

How File Handling Works

TimeProof takes a fundamentally different approach to file handling than most cloud services. Your files are never uploaded to TimeProof’s servers. Instead, the SHA-256 hash is computed locally in your browser, and only that hash — a fixed-length 64-character string — is sent to the server.

This means the “file size limit” question works differently here. There’s no upload bandwidth constraint, no server storage limit, and no file size cap imposed by the API. The only practical limit is your device’s ability to read and hash the file.

Practical Size Guidelines

File Size	Hashing Time	Experience
Up to 10 MB	Nearly instant	No noticeable delay
10–100 MB	1–3 seconds	Brief progress indicator
100 MB–1 GB	3–15 seconds	Progress bar visible
1–5 GB	15–60 seconds	Progress bar, wait for completion
5 GB+	1–5 minutes	Depends on device; may stress older hardware

These times are approximate and depend on your device’s CPU, available memory, and browser. Modern devices with adequate RAM handle multi-gigabyte files without issues.

Supported File Types

TimeProof works with any file type. The hashing algorithm operates on raw bytes — it doesn’t interpret or parse the file contents. Examples of files people timestamp:

Category	File Types
Documents	PDF, DOCX, TXT, ODT, RTF
Images	JPEG, PNG, TIFF, RAW, HEIC, WebP
Video	MP4, MOV, AVI, MKV, ProRes
Audio	MP3, WAV, FLAC, AAC
Code	Source files, repositories (as ZIP), build artifacts
Design	PSD, AI, FIGMA exports, SVG
Engineering	CAD files, STEP, STL, DWG
Archives	ZIP, TAR, 7Z, RAR
Data	CSV, JSON, XML, databases, spreadsheets
Legal	Contracts, NDAs, agreements (any format)

If your computer can read the file, TimeProof can timestamp it.

What Gets Sent to TimeProof

To be completely clear about what data leaves your machine:

Data	Sent to server?
File contents	No — never uploaded
File hash (SHA-256)	Yes — 64 characters
File name	Yes — for display purposes
File size	Yes — for metadata
File type/extension	No — inferred from name

The hash is a one-way function. It’s mathematically impossible to reconstruct your file from its hash. Even if someone obtained the hash, they would learn nothing about the file’s contents.

Browser Memory Considerations

Because hashing happens in the browser, very large files consume browser memory temporarily. Here’s how to handle large files:

Tips for Large Files

Close unnecessary tabs — free up browser memory before hashing large files
Use a modern browser — Chrome and Edge handle large files better than some alternatives
One file at a time — if hashing multiple large files, process them sequentially rather than all at once
Monitor the progress bar — the UI shows hashing progress so you know it’s working

If Hashing Fails

If a very large file causes the browser to run out of memory:

Try a different browser (Chrome tends to handle large allocations well)
Close other applications to free system memory
If the file is extremely large (10 GB+), consider using the API with a local hashing tool instead of the browser interface

Local Hashing Alternative

For very large files, you can compute the hash locally and submit it via the API:

# macOS / Linux
sha256sum largefile.bin

# Windows PowerShell
Get-FileHash largefile.bin -Algorithm SHA256

# Python
python -c "
import hashlib
with open('largefile.bin', 'rb') as f:
    h = hashlib.sha256()
    while chunk := f.read(8192):
        h.update(chunk)
    print(h.hexdigest())
"

Then submit the hash via the API’s POST /api/timestamps endpoint with the file hash, name, and size.

Batch File Considerations

When timestamping multiple files in a batch:

Each file is hashed individually
All hashes are combined into a Merkle tree
The Merkle root is what gets anchored on-chain
Large batches (hundreds of files) work fine — the Merkle tree construction is efficient

The total batch size doesn’t affect the blockchain cost — whether you batch 2 files or 200, the on-chain transaction is the same size (one Merkle root).

API Constraints

While the file itself isn’t uploaded, the API does have some practical limits on the request payload:

Constraint	Limit
Request body size	Standard HTTP limits
Files per request	Reasonable batch sizes
Hash format	64-character lowercase hex (SHA-256)
Filename length	Standard filesystem limits

These are API-level constraints on the metadata, not on the actual files.

Creating Your First Timestamp — step-by-step timestamp creation
Privacy and Your Files — how your data is protected
Batch Timestamping — efficiently timestamping many files
Troubleshooting Common Issues — fixing common problems