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go-dims

go-dims is a fast, lightweight HTTP microservice for real-time image processing, written in Go and powered by libvips. It’s a modern, drop-in replacement for mod_dims, fully compatible with the DIMS API.

Designed for use in websites, publishing platforms, and CDN-backed applications, go-dims helps you generate image variants on-the-fly — without the need for precomputing or storing multiple renditions.

✨ Features​

  • ✅ Resize, crop, rotate, flip, grayscale, and more
  • ✅ Add watermarks
  • ✅ Strip metadata, control quality, convert formats
  • ✅ Export in JPEG, PNG, and WebP
  • ✅ Sign and validate requests for secure public access
  • ✅ Load images from file, a URL, or S3
  • ✅ Deploy as a Docker image, or AWS Lambda function
  • ✅ Drop-in replacement for mod_dims

Why use go-dims?​

💡 On-demand image transformation

  • Resize, crop, convert formats, and more — all defined via URL.
  • Built-in support for signatures to prevent misuse and ensure cacheability.
  • Avoid bloated image storage by rendering variants only when requested.

⚡ Fast, minimal, portable

  • Built on libvips, the fastest image processing library.
  • Single static binary with zero runtime dependencies.
  • Docker image is just ~11MB compressed.
  • Built for linux/amd64 and linux/arm64.

🔒 Secure

  • Clean, HMAC-SHA256 signed URLs to ensure safe, tamperproof transformations.
  • The go-dims Docker image is built from scratch with a statically compiled binary, no shell, no package manager, and no extraneous libraries — minimizing the attack surface.

🛠 Developer-friendly

  • Easily define image variants directly in frontend code or templates.
  • Uses minimal memory — perfect for local development.
  • Runs equally well locally, in containers, or as an AWS Lambda function.

📦 Deployment Options​

  • Static binary: Just download and run.
  • Standalone Docker: Launch anywhere in seconds.
  • AWS Lambda: Compile and deploy as a fast, small Lambda function.

License​

go-dims is licensed under the MIT license. See the LICENSE file for details.

For software used by this project, and their licenses, see the NOTICE file.