Hash Deduplication - SimpleHost

How It Works

When you update an existing site, SimpleHost compares SHA-256 hashes of each file against the previous version. Files that haven’t changed are copied server-side — no re-upload needed. This makes updates fast, even for large sites with hundreds of files.

The Flow

Send manifest with hashes

Include the hash field for each file in your update request:

{
  "files": [
    {"path": "index.html", "size": 2048, "contentType": "text/html", "hash": "abc123..."},
    {"path": "style.css", "size": 512, "contentType": "text/css", "hash": "def456..."}
  ]
}

API compares hashes

The API checks each file’s hash against the same file path in the previous version.

Matching files are skipped

Files with identical hashes appear in the skipped array — they’re copied internally, no upload needed.

Upload only changed files

Only files in the uploads array need to be uploaded.

Example Response

If you update a site where only index.html changed:

{
  "upload": {
    "uploads": [
      {"path": "index.html", "url": "...", "headers": {"Content-Type": "text/html"}}
    ],
    "skipped": [
      {"path": "style.css", "reason": "hash_match"},
      {"path": "logo.png", "reason": "hash_match"},
      {"path": "app.js", "reason": "hash_match"}
    ]
  }
}

Only 1 file needs uploading. The other 3 are copied server-side instantly.

Computing Hashes

The hash must be a SHA-256 hex digest (64 lowercase hex characters).

macOS

shasum -a 256 index.html | cut -d' ' -f1

Linux

sha256sum index.html | cut -d' ' -f1

Node.js

const crypto = require('crypto');
const fs = require('fs');

const hash = crypto.createHash('sha256')
  .update(fs.readFileSync('index.html'))
  .digest('hex');

Python

import hashlib

with open('index.html', 'rb') as f:
    hash = hashlib.sha256(f.read()).hexdigest()

The publish.sh script handles hashing automatically. You only need to compute hashes manually if you’re building a custom integration with the API.

Without Hashes

If you omit the hash field, every file is treated as new and must be uploaded. Always include hashes when updating to get the performance benefit.

​How It Works

​The Flow

​Example Response

​Computing Hashes

​macOS

​Linux

​Node.js

​Python

​Without Hashes

How It Works

The Flow

Example Response

Computing Hashes

macOS

Linux

Node.js

Python

Without Hashes