diff --git a/internal/api/openapi/repo.go b/internal/api/openapi/repo.go
index fcdcd1ae5..6176df444 100644
--- a/internal/api/openapi/repo.go
+++ b/internal/api/openapi/repo.go
@@ -120,6 +120,11 @@ type listTagsRequest struct {
 	repoRequest
 }
 
+type getRawDiffRequest struct {
+	repoRequest
+	Range string `path:"range" example:"main..dev"`
+}
+
 var queryParameterGitRef = openapi3.ParameterOrRef{
 	Parameter: &openapi3.Parameter{
 		Name: request.QueryParamGitRef,
@@ -434,4 +439,14 @@ func repoOperations(reflector *openapi3.Reflector) {
 	_ = reflector.SetJSONResponse(&opCommitFiles, new(usererror.Error), http.StatusForbidden)
 	_ = reflector.SetJSONResponse(&opCommitFiles, new(usererror.Error), http.StatusNotFound)
 	_ = reflector.Spec.AddOperation(http.MethodPost, "/repos/{repo_ref}/commits", opCommitFiles)
+
+	opRawDiff := openapi3.Operation{}
+	opRawDiff.WithTags("repository")
+	opRawDiff.WithMapOfAnything(map[string]interface{}{"operationId": "rawDiff"})
+	_ = reflector.SetRequest(&opRawDiff, new(getRawDiffRequest), http.MethodGet)
+	_ = reflector.SetStringResponse(&opRawDiff, http.StatusOK, "text/plain")
+	_ = reflector.SetJSONResponse(&opRawDiff, new(usererror.Error), http.StatusInternalServerError)
+	_ = reflector.SetJSONResponse(&opRawDiff, new(usererror.Error), http.StatusUnauthorized)
+	_ = reflector.SetJSONResponse(&opRawDiff, new(usererror.Error), http.StatusForbidden)
+	_ = reflector.Spec.AddOperation(http.MethodGet, "/repos/{repo_ref}/compare/{range}", opRawDiff)
 }