Manage Openapi Overlays

manage-openapi-overlays

Overlays let you customize an OpenAPI spec for SDK generation without modifying the source. This skill covers creating overlay files, applying them to specs, and using them to fix validation errors.

Authentication

Set SPEAKEASY_API_KEY env var or run speakeasy auth login.

When to Use

• You need to customize SDK output but cannot modify the source spec
• Adding x-speakeasy extensions for grouping, naming, or retries
• Fixing lint issues without editing the original file
• Applying an existing overlay file to a spec
• Testing overlay changes before adding to workflow
• Lint errors exist but the source spec cannot be edited
• Adding missing descriptions, tags, or operation names via overlay
• User says: "create overlay", "apply overlay", "customize SDK", "can't modify spec", "fix with overlay"

Inputs

Outputs

Commands

Generate an Overlay by Comparing Specs

speakeasy overlay compare -b <before-spec> -a <after-spec> -o <output-overlay>

Use this when you have a modified version of a spec and want to capture the differences as a reusable overlay.

Apply an Overlay to a Spec

speakeasy overlay apply -s <spec-path> -o <overlay-path> --out <output-path>

Validate an Overlay

speakeasy overlay validate -o <overlay-path>

Creating an Overlay Manually

Create an overlay file with this structure:

overlay: 1.0.0
info:
  title: My Overlay
  version: 1.0.0
actions:
  - target: "$.paths['/example'].get"
    update:
      x-speakeasy-group: example
      x-speakeasy-name-override: getExample

Each action has a target (JSONPath expression) and an update (object to merge) or remove (boolean to delete the target).

Example: SDK Method Naming and Grouping

overlay: 1.0.0
info:
  title: SDK Customizations
  version: 1.0.0
actions:
  - target: "$.paths['/users'].get"
    update:
      x-speakeasy-group: users
      x-speakeasy-name-override: list
  - target: "$.paths['/users'].post"
    update:
      x-speakeasy-group: users
      x-speakeasy-name-override: create
  - target: "$.paths['/users/{id}'].get"
    update:
      x-speakeasy-group: users
      x-speakeasy-name-override: get
  - target: "$.paths['/users/{id}'].delete"
    update:
      x-speakeasy-group: users
      x-speakeasy-name-override: delete
      deprecated: true

This produces SDK methods: sdk.users.list(), sdk.users.create(), sdk.users.get(), sdk.users.delete().

Example: Apply Overlay

# Apply overlay and write merged spec
speakeasy overlay apply -s openapi.yaml -o sdk-overlay.yaml --out openapi-modified.yaml

# Compare two specs to generate an overlay
speakeasy overlay compare -b original.yaml -a modified.yaml -o changes-overlay.yaml

Using in Workflow (Recommended)

Instead of applying overlays manually, add them to .speakeasy/workflow.yaml:

sources:
  my-api:
    inputs:
      - location: ./openapi.yaml
    overlays:
      - location: ./naming-overlay.yaml
      - location: ./grouping-overlay.yaml

Overlays are applied in order. Later overlays can override earlier ones. This approach ensures overlays are always applied during speakeasy run.

Common Fix Patterns

Use overlays to fix validation issues when you cannot edit the source spec.

Fix Workflow

# 1. Validate the spec to identify issues
speakeasy lint openapi --non-interactive -s openapi.yaml

# 2. Create an overlay file targeting each issue (see patterns above)

# 3. Add overlay to workflow.yaml under sources.overlays

# 4. Regenerate the SDK
speakeasy run --output console

JSONPath Targeting Reference

What NOT to Do

• Do NOT use overlays for invalid YAML/JSON syntax errors -- fix the source file
• Do NOT try to fix broken $ref paths with overlays -- fix the source spec
• Do NOT use overlays to fix wrong data types -- this is an API design issue
• Do NOT try to deduplicate schemas with overlays -- requires structural analysis
• Do NOT ignore errors that require source spec fixes -- overlays cannot solve everything
• Do NOT modify source OpenAPI specs directly if they are externally managed
• Do NOT use a speakeasy overlay create command -- it does not exist

Troubleshooting

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