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infisical/docs/self-hosting/guides/cdn-caching.mdx

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---
title: "CDN Caching for Static Assets"
description: "How to set up CDN caching to prevent version skew issues during deployments"
---
This guide explains a common issue with frontend asset caching during deployments and how to solve it using a CDN.
## The Problem: Version Skew
Modern frontend build tools like Vite generate content-hashed filenames for static assets (e.g., `main-abc123.js`). Each build produces unique filenames based on file contents. During deployments, this can cause a race condition:
1. User loads `index.html` which references `main-abc123.js`
2. New deployment replaces containers with a new build
3. New containers only serve `main-xyz789.js` (new build)
4. User's browser requests `main-abc123.js` from cached HTML
5. Request returns **404** — the old asset no longer exists
This results in broken pages, failed SPA navigation, and requires users to manually refresh.
<Note>
This is a documented limitation in Vite's official guidance: [Load Error Handling](https://vite.dev/guide/build#load-error-handling)
</Note>
### Current Behavior
Infisical includes a built-in workaround that detects version mismatches and triggers a page reload. While functional, this introduces a noticeable delay for users during deployments.
## The Solution: External Asset Storage
The solution is to store static assets externally (e.g., S3, GCS, Azure Blob) and serve them through a CDN (e.g., CloudFront, Cloud CDN, Cloudflare). Assets are uploaded **before** container deployment, ensuring old versions remain available.
### How It Works
```mermaid
flowchart LR
User[User Browser]
CDN[CDN]
S3[(Object Storage)]
App[Your Infrastructure]
User --> CDN
CDN -->|"/assets/*"| S3
CDN -->|"/* (default)"| App
```
The key points:
- **Asset persistence**: Old assets remain available even after new deployments
- **Deployment order**: Upload new assets before deploying new containers
- **Long cache TTL**: Content-hashed files can be cached indefinitely (we recommend 30 days)
- **Automatic cleanup**: Configure lifecycle rules to expire old assets after 30 days
At Infisical, we use **CloudFront + S3** for this purpose, but you can use any CDN and object storage combination that fits your infrastructure.
## Exporting Assets
Infisical provides a built-in command to export frontend assets from the Docker image:
```bash
# Export as tar archive to stdout
docker run --rm infisical/infisical npm run --silent assets:export > assets.tar
# Extract the archive
tar -xf assets.tar
ls assets/ # Content-hashed JS/CSS files
```
Or export directly to a mounted directory:
```bash
docker run --rm -v $(pwd)/cdn-assets:/output \
infisical/infisical npm run --silent assets:export /output
```
### What Gets Exported
The command exports the `/assets` directory containing:
- JavaScript bundles (e.g., `main-abc123.js`, `chunk-def456.js`)
- CSS files (e.g., `styles-789xyz.css`)
- Other static assets with content hashes
These files are safe to cache with long TTLs because their filenames change whenever the content changes.
## Integration with Your Pipeline
The general deployment flow should be:
1. **Build** your new Docker image (or pull the official Infisical image)
2. **Export** assets using `npm run assets:export`
3. **Upload** assets to your object storage
4. **Deploy** the new container version
```bash
# Example: Export and upload to S3
docker run --rm infisical/infisical:$VERSION npm run --silent assets:export > assets.tar
tar -xf assets.tar
aws s3 sync assets s3://your-bucket/assets --cache-control "public, max-age=2592000"
# Then deploy your container
```
<Warning>
Always upload assets **before** deploying the new container. This ensures the assets referenced by the new `index.html` exist before users can access them.
</Warning>