Automate building and signing your WebExtension with Mozilla's web-ext tool using Github Actions.

Add a new workflow by creating a .yml file under .github/workflows.

name: Builds, signs and publishes the WebExtension
on:
  push:
    branches:
      - master

jobs:
  publish-to-amo:
    name: Build and publish the extension
    runs-on: ubuntu-latest
    steps:
      - name: Pull and checkout source
        uses: actions/checkout@master

      - name: Sign the web-ext
        uses: saphareas/sign-web-extension-action@master
        with:
          web-ext-id: "{your extension uuid}"
          sign-listed: true
          amo-api-key: ${{ secrets.AMO_API_KEY }}
          amo-api-secret: ${{ secrets.AMO_API_SECRET }}

amo-api-key: Your key for Mozilla's API

amo-api-secret: Your secret for Mozilla's API

web-ext-id: UUID of your existing extension. Signing new extensions is not supported.

sign-listed: Set to true to list the extension on AMO. Defaults to false for unlisted signing.

Note that the action will always return a failed state for listed signing, because Mozilla doesn't support automated listed signing. Your extension will be submitted for review instead.

TL;DR Listed signing will fail but your extension will be updated anyways.