Download System
How Continuata's download system works from the user's perspective and the technical implementation details.
User Experience
Downloads work directly in Chrome, Edge, and other Chromium browsers — no installation required. Safari and Firefox users install the free Continuata Bridge for the same experience (the download page explains why with a collapsed "Why do I need the Bridge?" note). Downloads need a Mac or PC — phones aren't supported.
Click Download Link
Customer receives a download URL by email after purchase, or finds all their purchases at continuata.io/my by entering their email.
Choose Location
Browser prompts for a folder using the native picker. First download: pick a regular, empty folder. Downloading an update? The page detects it from download history and says so: pick the same folder the product is already in — only changed files are fetched. A new empty folder still works but re-downloads everything.
Download with Progress
Real-time progress, speed indicators, and pause/resume controls. Closing the tab mid-transfer triggers the browser's "leave site?" warning; a paused download doesn't.
Verification & Completion
Automatic integrity verification and completion summary. The headline holds at 99% while packs are still extracting — 100% means the install is genuinely complete, so don't close the tab at "99%".
Technical Architecture
Pack-Based Downloads
Files are grouped into ~8MB packs for transport. The downloader fetches packs in parallel (up to 16 connections, adapting to your connection), verifies each pack's SHA-256, then extracts and verifies each individual file before writing it to disk:
Benefits
- Fewer HTTP requests (e.g. 150 packs vs 5,000 files)
- Resume from last completed pack
- Per-pack and per-file integrity verification
- Automatic retry with backoff on failure
How It Works
- Download pack → verify SHA-256
- Extract files using segment offsets
- Verify each file's SHA-256
- Write verified files to disk
File System Integration
Different approaches based on browser capabilities:
File System Access API (Chrome, Edge)
Direct file system access allows writing files to user-selected folders in real-time during download.
OPFS Scratch Staging (Chrome, Edge)
On fast connections, packs are staged in the Origin Private File System so fetching isn't limited by disk write speed, then extracted to your chosen folder.
Continuata Bridge
Free desktop app provides native file system access — required on Safari and Firefox. Download at continuata.io/bridge.
Progress Tracking
Real-time download progress with detailed metrics:
Overall Progress
Percentage complete, bytes downloaded, total size.
Current File
Active file name, file progress, circular indicator.
Performance
Download speed, ETA, active connections.
Browser Compatibility
Chrome
Full native support
Edge
Full native support
Firefox
Bridge required
Safari
Bridge required
Customer Portal
Every customer can find all their Continuata purchases — across every vendor they've bought from — at continuata.io/my. They enter the email they used at checkout and we send a secure, time-limited link to their library. Purchases display as a card grid, and each card shows its own update state:
Download
Never downloaded yet — first-time download button.
Update available
A completed download of an older version exists. Shows the version delta (e.g. v1.0.0 → v1.1.0) and an Update button — into the same folder, it fetches only what changed.
Up to date
Already on the live version, with a quiet "Download again" for reinstalls.
Unavailable
The product isn't currently published by the vendor.
- No password — verification is via emailed link
- A single inbox can list purchases from multiple vendors
- Customers can add and verify additional emails (handy when they purchased under different addresses)
- Link this from your post-purchase emails so customers always know where to recover their downloads — and where they'll spot updates without waiting for your announcement email
Resume Downloads
Download progress is automatically persisted in the browser's IndexedDB. If the page is closed, refreshed, or the connection drops mid-download, a Resume button appears on the next visit. The download picks up from the last completed pack — no data needs to be re-downloaded.
- Works across page refresh, tab close, and browser restart
- Progress tracked at the pack level — completed packs are never re-fetched
- The same download folder is re-used automatically (no folder picker prompt on resume)
- A resume within 24 hours continues the same download session, so your Downloads log shows one row per real download attempt — not one per retry
Rate Limits
Genuinely new download starts from the same link are throttled to protect against abuse: a 60-second cooldown per link (and per IP), and at most 20 fresh sessions per link per hour. A customer who trips this sees "Too many download requests. Please wait a few seconds and try again." or "Download limit reached for this link. Please try again later." Legitimate resumes never hit these limits.
Accessibility
The download page announces status changes to screen readers (fetching, downloading, paused, complete, errors), and the progress bar exposes standard progressbar semantics — e.g. "42% — 3 of 7 packs".
Security Features
Data Integrity
- SHA-256 verification per pack (after download)
- SHA-256 verification per file (after extraction)
- Automatic retry with backoff on pack failure
- SHA-256-verified manifests
Access Control
- Time-limited, unguessable download tokens
- Automatic link refresh via verified email
- Per-session audit logging (IP and client recorded)
- Per-token usage tracking
Next Steps: Learn how to create download tokens or explore download analytics to track usage.