diff --git a/.github/.yamllint.yml b/.github/.yamllint.yml
new file mode 100644
index 000000000..d2036e700
--- /dev/null
+++ b/.github/.yamllint.yml
@@ -0,0 +1,73 @@
+# See: https://yamllint.readthedocs.io/en/stable/configuration.html
+# The code style defined in this file is the official standardized style to be used in all Arduino projects and should
+# not be modified.
+# Note: Rules disabled solely because they are redundant to Prettier are marked with a "Prettier" comment.
+
+rules:
+  braces:
+    level: error
+    forbid: non-empty
+    min-spaces-inside: -1 # Prettier
+    max-spaces-inside: -1 # Prettier
+    min-spaces-inside-empty: -1 # Prettier
+    max-spaces-inside-empty: -1 # Prettier
+  brackets:
+    level: error
+    forbid: non-empty
+    min-spaces-inside: -1 # Prettier
+    max-spaces-inside: -1 # Prettier
+    min-spaces-inside-empty: -1 # Prettier
+    max-spaces-inside-empty: -1 # Prettier
+  colons: disable # Prettier
+  commas: disable # Prettier
+  comments: disable # Prettier
+  comments-indentation: disable # Prettier
+  document-end: disable # Prettier
+  document-start: disable
+  empty-lines: disable # Prettier
+  empty-values: disable
+  hyphens: disable # Prettier
+  indentation: disable # Prettier
+  key-duplicates: disable # Prettier
+  key-ordering: disable
+  line-length:
+    level: warning
+    max: 120
+    allow-non-breakable-words: true
+    allow-non-breakable-inline-mappings: true
+  new-line-at-end-of-file: disable # Prettier
+  new-lines: disable # Prettier
+  octal-values:
+    level: warning
+    forbid-implicit-octal: true
+    forbid-explicit-octal: false
+  quoted-strings: disable
+  trailing-spaces: disable # Prettier
+  truthy:
+    level: error
+    allowed-values:
+      - "true"
+      - "false"
+      - "on" # Used by GitHub Actions as a workflow key.
+    check-keys: true
+
+yaml-files:
+  # Source: https://github.com/ikatyang/linguist-languages/blob/master/data/YAML.json (used by Prettier)
+  - ".clang-format"
+  - ".clang-tidy"
+  - ".gemrc"
+  - ".yamllint"
+  - "glide.lock"
+  - "*.yml"
+  - "*.mir"
+  - "*.reek"
+  - "*.rviz"
+  - "*.sublime-syntax"
+  - "*.syntax"
+  - "*.yaml"
+  - "*.yaml-tmlanguage"
+  - "*.yaml.sed"
+  - "*.yml.mysql"
+
+ignore: |
+  /.git/
diff --git a/.github/workflows/check-workflows.yml b/.github/workflows/check-workflows.yml
new file mode 100644
index 000000000..d6646c9b8
--- /dev/null
+++ b/.github/workflows/check-workflows.yml
@@ -0,0 +1,58 @@
+name: Check Workflows
+
+# See: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows
+on:
+  push:
+    paths:
+      - ".github/workflows/*.yaml"
+      - ".github/workflows/*.yml"
+  pull_request:
+    paths:
+      - ".github/workflows/*.yaml"
+      - ".github/workflows/*.yml"
+  schedule:
+    # Run every Tuesday at 8 AM UTC to catch breakage resulting from changes to the JSON schema.
+    - cron: "0 8 * * TUE"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Download JSON schema for GitHub Actions workflows
+        id: download-schema
+        uses: carlosperate/download-file-action@v1.0.3
+        with:
+          # See: https://github.com/SchemaStore/schemastore/blob/master/src/schemas/json/github-workflow.json
+          file-url: https://json.schemastore.org/github-workflow
+          location: ${{ runner.temp }}/github-workflow-schema
+          file-name: github-workflow.json
+
+      - name: Get week number for use in cache key
+        id: get-date
+        run: |
+          echo "::set-output name=week-number::$(date --utc '+%V')"
+
+      - name: Load dependencies cache
+        uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-ajv-cli-${{ steps.get-date.outputs.week-number }}
+          restore-keys: |
+            ${{ runner.os }}-node-ajv-cli-
+
+      - name: Install JSON schema validator
+        run: sudo npm install --global ajv-cli
+
+      - name: Validate GitHub Actions workflows
+        run: |
+          # See: https://github.com/ajv-validator/ajv-cli#readme
+          ajv validate \
+            --strict=false \
+            -s "${{ steps.download-schema.outputs.file-path }}" \
+            -d "./.github/workflows/*.{yml,yaml}"
diff --git a/.github/workflows/check-yaml.yml b/.github/workflows/check-yaml.yml
new file mode 100644
index 000000000..4756ae191
--- /dev/null
+++ b/.github/workflows/check-yaml.yml
@@ -0,0 +1,78 @@
+name: Check YAML
+
+# See: https://docs.github.com/en/free-pro-team@latest/actions/reference/events-that-trigger-workflows
+on:
+  push:
+    paths:
+      - ".github/workflows/check-yaml.yml"
+      - ".yamllint*"
+      # Source: https://github.com/ikatyang/linguist-languages/blob/master/data/YAML.json (used by Prettier)
+      - "**/.clang-format"
+      - "**/.clang-tidy"
+      - "**/.gemrc"
+      - "**/glide.lock"
+      - "**.yml"
+      - "**.mir"
+      - "**.reek"
+      - "**.rviz"
+      - "**.sublime-syntax"
+      - "**.syntax"
+      - "**.yaml"
+      - "**.yaml-tmlanguage"
+      - "**.yaml.sed"
+      - "**.yml.mysql"
+  pull_request:
+    paths:
+      - ".github/workflows/check-yaml.yml"
+      - ".yamllint*"
+      - "**/.clang-format"
+      - "**/.clang-tidy"
+      - "**/.gemrc"
+      - "**/glide.lock"
+      - "**.yml"
+      - "**.mir"
+      - "**.reek"
+      - "**.rviz"
+      - "**.sublime-syntax"
+      - "**.syntax"
+      - "**.yaml"
+      - "**.yaml-tmlanguage"
+      - "**.yaml.sed"
+      - "**.yml.mysql"
+  schedule:
+    # Run every Tuesday at 8 AM UTC to catch breakage caused by changes to yamllint.
+    - cron: "0 8 * * TUE"
+  workflow_dispatch:
+  repository_dispatch:
+
+jobs:
+  check:
+    name: ${{ matrix.configuration.name }}
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+
+      matrix:
+        configuration:
+          - name: Generate problem matcher output
+            # yamllint's "github" output type produces annotated diffs, but is not useful to humans reading the log.
+            format: github
+            # The other matrix job is used to set the result, so this job is configured to always pass.
+            continue-on-error: true
+          - name: Check formatting
+            # yamllint's "colored" output type is most suitable for humans reading the log.
+            format: colored
+            continue-on-error: false
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Check YAML
+        continue-on-error: ${{ matrix.configuration.continue-on-error }}
+        run: |
+          yamllint \
+            --config-file "${{ github.workspace }}/.github/.yamllint.yml" \
+            --format ${{ matrix.configuration.format }} \
+            .
diff --git a/.github/workflows/spell-check.yml b/.github/workflows/spell-check.yml
index 8f7b71ade..3cf53c77a 100644
--- a/.github/workflows/spell-check.yml
+++ b/.github/workflows/spell-check.yml
@@ -25,7 +25,7 @@ jobs:
         uses: codespell-project/actions-codespell@master
         with:
           # In the event of a false positive, add the problematic word, in all lowercase, to a comma-separated list here:
-          ignore_words_list:
+          ignore_words_list: ""
           builtin: clear,informal,en-GB_to_en-US
           check_filenames: true
           check_hidden: true