diff --git a/.changesets/1793024465-e6de07b9.yaml b/.changesets/1793024465-e6de07b9.yaml
new file mode 100644
index 000000000..8e2334e48
--- /dev/null
+++ b/.changesets/1793024465-e6de07b9.yaml
@@ -0,0 +1,10 @@
+id: 1793024465-e6de07b9
+features:
+    - core
+targets:
+    - ruby
+type: fix
+bump: patch
+description: accept acronyms such as SDK or API in the module name
+author: 2ynn
+date: "2026-10-26"
diff --git a/pkg/templates/validation_regex_test.go b/pkg/templates/validation_regex_test.go
new file mode 100644
index 000000000..72d665f30
--- /dev/null
+++ b/pkg/templates/validation_regex_test.go
@@ -0,0 +1,124 @@
+package templates
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/mitchellh/mapstructure"
+	"github.com/speakeasy-api/openapi-generation/v2/internal/executor"
+	"github.com/speakeasy-api/openapi-generation/v2/internal/types"
+	config "github.com/speakeasy-api/sdk-gen-config"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// goja's RegExp.source emits an unescaped "/" as the Unicode escape below, which the CLI rewrites before compiling the pattern with Go's regexp.
+const escapedSlash = `\u002f`
+
+type validationField struct {
+	config.SDKGenConfigField `mapstructure:",squash"`
+	ValidationExamples       struct {
+		Valid   []string
+		Invalid []string
+	}
+	// Declared on some fields in config.ts but read by neither the generator nor the CLI.
+	ValidationFunc any
+}
+
+func TestValidationRegexes(t *testing.T) {
+	t.Parallel()
+
+	t.Run("common", func(t *testing.T) {
+		t.Parallel()
+
+		e, err := executor.New(types.NewTargetFromTemplate("common"), "common/config.ts")
+		require.NoError(t, err)
+
+		for _, newSDK := range []bool{false, true} {
+			rawFields, err := e.Run("getCommonConfigFields", newSDK)
+			require.NoError(t, err)
+
+			checkValidationFields(t, decodeValidationFields(t, rawFields), newSDK)
+		}
+	})
+
+	for _, name := range GetAvailableTemplates() {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			target := types.NewTargetFromTemplate(name)
+			e, err := executor.New(target, "config.ts")
+			require.NoError(t, err)
+
+			for _, newSDK := range []bool{false, true} {
+				_, err := GetLanguageConfigFields(target, newSDK)
+				require.NoError(t, err)
+
+				commonFields, err := getCommonConfigFields(newSDK)
+				require.NoError(t, err)
+
+				rawFields, err := e.Run("getConfigFields", commonFields, newSDK)
+				require.NoError(t, err)
+
+				checkValidationFields(t, decodeValidationFields(t, rawFields), newSDK)
+			}
+		})
+	}
+}
+
+func decodeValidationFields(t *testing.T, rawFields any) map[string]validationField {
+	t.Helper()
+
+	rawFieldMap, ok := rawFields.(map[string]any)
+	require.True(t, ok, "config fields are %T", rawFields)
+
+	fields := map[string]validationField{}
+	for key, rawField := range rawFieldMap {
+		// Common fields passed through unchanged arrive as Go structs and are checked by the "common" subtest.
+		if _, ok := rawField.(map[string]any); !ok {
+			continue
+		}
+
+		var field validationField
+		decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{ErrorUnused: true, Result: &field})
+		require.NoError(t, err)
+		require.NoError(t, decoder.Decode(rawField), "field %q", key)
+		fields[key] = field
+	}
+
+	return fields
+}
+
+func checkValidationFields(t *testing.T, fields map[string]validationField, newSDK bool) {
+	t.Helper()
+
+	for key, field := range fields {
+		if field.ValidationRegex == nil {
+			assert.Empty(t, field.ValidationExamples.Valid, "field %q (newSDK=%v): valid examples without a ValidationRegex", key, newSDK)
+			assert.Empty(t, field.ValidationExamples.Invalid, "field %q (newSDK=%v): invalid examples without a ValidationRegex", key, newSDK)
+			continue
+		}
+
+		pattern := strings.ReplaceAll(*field.ValidationRegex, escapedSlash, "/")
+		regex, err := regexp.Compile(pattern)
+		require.NoError(t, err, "field %q (newSDK=%v)", key, newSDK)
+
+		if field.DefaultValue != nil {
+			defaultValue := fmt.Sprintf("%v", *field.DefaultValue)
+			assert.True(t, regex.MatchString(defaultValue),
+				"field %q (newSDK=%v): default %q does not match %s", key, newSDK, defaultValue, pattern)
+		}
+
+		for _, value := range field.ValidationExamples.Valid {
+			assert.True(t, regex.MatchString(value),
+				"field %q (newSDK=%v): valid example %q does not match %s", key, newSDK, value, pattern)
+		}
+
+		for _, value := range field.ValidationExamples.Invalid {
+			assert.False(t, regex.MatchString(value),
+				"field %q (newSDK=%v): invalid example %q matches %s", key, newSDK, value, pattern)
+		}
+	}
+}
diff --git a/templates/templates/common/common/typeDefs.d.ts b/templates/templates/common/common/typeDefs.d.ts
index f54e0e682..03d8b95a4 100644
--- a/templates/templates/common/common/typeDefs.d.ts
+++ b/templates/templates/common/common/typeDefs.d.ts
@@ -2694,6 +2694,10 @@ declare global {
     SecretName?: string;
     ValidationRegex?: string;
     ValidationMessage?: string;
+    ValidationExamples?: {
+      valid?: string[];
+      invalid?: string[];
+    };
   };
 
   type SDKGenConfigFields = Record<string, SDKGenConfigField>;
diff --git a/templates/templates/ruby/config.ts b/templates/templates/ruby/config.ts
index 0d2eb7c59..39311d66b 100644
--- a/templates/templates/ruby/config.ts
+++ b/templates/templates/ruby/config.ts
@@ -238,9 +238,20 @@ function getConfigFields(
       DefaultValue: "OpenApiSdk",
       Description:
         "The top level module names for your sdk https://ruby-doc.org/3.2.6/syntax/modules_and_classes_rdoc.html",
-      ValidationRegex: /^([A-Z][a-z0-9]+)+$/.source,
+      ValidationRegex: /^[A-Z][A-Za-z0-9]*$/.source,
       ValidationMessage:
         "Module names should be PascalCase and have no special chars",
+      ValidationExamples: {
+        valid: ["AcmeRubySDK", "OpenAPI", "SDK", "Acme2", "A"],
+        invalid: [
+          "openApiSdk",
+          "Open_Api",
+          "Open::Api",
+          "Open-Api",
+          "2Acme",
+          "",
+        ],
+      },
     },
     additionalDependencies: {
       Name: "additionalDependencies",