Detect 27 types of API changes — 17 breaking, 10 non-breaking — before they reach production. Runs in CI, in your terminal, or in the browser.
A breaking change is any modification to an API that causes existing clients to fail. Removing an endpoint, changing a field type from string to integer, or adding a new required parameter — these all break clients that rely on the previous contract.
Breaking changes in production cause outages, support tickets, and lost trust. Delimit catches them at the pull request stage — before merge, before deploy, before anyone notices.
| Type | Description | Severity |
|---|---|---|
| endpoint_removed | An API endpoint was removed entirely | high |
| method_removed | An HTTP method (GET, POST, etc.) was removed from an endpoint | high |
| required_param_added | A new required parameter was added to an operation | high |
| param_removed | A parameter was removed from an operation | high |
| response_removed | A response status code was removed | high |
| required_field_added | A new required field was added to a request body | high |
| field_removed | A field was removed from a response schema | high |
| type_changed | A schema property type was changed (e.g., string to integer) | high |
| format_changed | A schema property format was changed (e.g., int32 to int64) | medium |
| enum_value_removed | An allowed enum value was removed | high |
| param_type_changed | A parameter type was changed | high |
| param_required_changed | A parameter changed from optional to required | high |
| response_type_changed | A response schema type was changed | high |
| security_removed | A security requirement was removed | medium |
| security_scope_removed | An OAuth scope was removed from a security requirement | medium |
| max_length_decreased | A maxLength constraint was made more restrictive | medium |
| min_length_increased | A minLength constraint was made more restrictive | medium |
| Type | Description |
|---|---|
| endpoint_added | A new API endpoint was added |
| method_added | A new HTTP method was added to an endpoint |
| optional_param_added | A new optional parameter was added |
| response_added | A new response status code was added |
| optional_field_added | A new optional field was added to a schema |
| enum_value_added | A new enum value was added |
| description_changed | A description or summary was updated |
| security_added | A new security requirement was added |
| deprecated_added | A deprecation marker was added |
| default_changed | A default value was changed |
Runs on every PR. Posts a comment with all detected changes, severity grades, and migration steps. Blocks merge on breaking changes.
Run locally or in any CI pipeline. Returns exit code 1 on policy violation so you can gate deployments.
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