Docker & Heroku: Fixing the “error from registry: unsupported” Error

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Docker & Heroku: Fixing the “error from registry: unsupported” Error
Docker & Heroku: Fixing the “error from registry: unsupported” Error896×1344 67.9 KB

When working with Docker and deploying your applications to Heroku, you might run into this cryptic message:

error from registry: unsupported
unsupported
Error: docker push exited with Error: 1

This error can be confusing and frustrating — especially since it gives very little detail. In this blog post, we’ll break down what this error means, why it happens, and how to fix it step by step.

The Error

If you’re trying to push your Docker image to Heroku’s container registry using a command like:

docker push registry.heroku.com/your-app-name/web

And you see:

error from registry: unsupported
unsupported
Error: docker push exited with Error: 1

It means that Heroku does not support the format or architecture of your Docker image.

Why This Happens

There are two common reasons this error occurs:

1. Wrong Platform Architecture

If you’re using a Mac with an Apple Silicon (M1/M2) chip or building images using Docker Buildx, you might be generating an image for the linux/arm64 platform — but Heroku only supports linux/amd64.

2. Image Format Not Supported

Heroku expects Docker images in a traditional Docker V2 format. Sometimes, using tools like Docker Buildx can create images in an OCI (Open Container Initiative) format, which Heroku’s registry doesn’t recognize.

How to Fix It

Step 1: Set the Platform to linux/amd64

Before building the image, force Docker to use the architecture Heroku supports:

On Mac/Linux (bash):

export DOCKER_DEFAULT_PLATFORM=linux/amd64

On Windows PowerShell:

$env:DOCKER_DEFAULT_PLATFORM = "linux/amd64"

This tells Docker to use the amd64 architecture even if your machine uses ARM.

Step 2: Build the Docker Image

Use the standard Docker build command without buildx:

docker build --platform linux/amd64 -t registry.heroku.com/your-app-name/web .

This ensures your image uses the correct platform and format.

Step 3: Log in to Heroku Container Registry

If you haven’t already, log in:

heroku container:login

Step 4: Push the Image

Now push the image to Heroku:

docker push registry.heroku.com/your-app-name/web

You should no longer see the “unsupported” error.

Step 5: Release the Image

After pushing successfully, release it on Heroku:

heroku container:release web --app your-app-name

Optional: Test Locally Before Pushing

You can also test your Docker image locally to ensure it runs as expected:

docker run -p 5000:5000 registry.heroku.com/your-app-name/web

Still Seeing Issues?

Double-check:

  • Your Docker version is up to date.
  • You’re not using buildx or experimental Docker features.
  • Your image is tagged properly (registry.heroku.com/your-app-name/web).

Summary

Problem Solution
error from registry: unsupported Use --platform linux/amd64 during build
Heroku rejects image Avoid buildx or OCI image formats
You’re using an M1/M2 Mac Set DOCKER_DEFAULT_PLATFORM=linux/amd64

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