diff --git a/pkg/config/engine/api.go b/pkg/config/engine/api.go
index bc6c4a68..8c7d1b50 100644
--- a/pkg/config/engine/api.go
+++ b/pkg/config/engine/api.go
@@ -18,12 +18,13 @@ package engine
 
 // Interface defines the API for a runtime config updater.
 type Interface interface {
-	DefaultRuntime() string
 	AddRuntime(string, string, bool) error
-	Set(string, interface{})
+	DefaultRuntime() string
+	GetRuntimeConfig(string) (RuntimeConfig, error)
 	RemoveRuntime(string) error
 	Save(string) (int64, error)
-	GetRuntimeConfig(string) (RuntimeConfig, error)
+	Set(string, interface{})
+	String() string
 }
 
 // RuntimeConfig defines the interface to query container runtime handler configuration
diff --git a/pkg/config/engine/containerd/config_v1_test.go b/pkg/config/engine/containerd/config_v1_test.go
index 787ab30b..ca82032a 100644
--- a/pkg/config/engine/containerd/config_v1_test.go
+++ b/pkg/config/engine/containerd/config_v1_test.go
@@ -200,20 +200,21 @@ func TestAddRuntimeV1(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.description, func(t *testing.T) {
-			cfg, err := toml.Load(tc.config)
-			require.NoError(t, err)
 			expectedConfig, err := toml.Load(tc.expectedConfig)
 			require.NoError(t, err)
 
-			c := &ConfigV1{
-				Logger: logger,
-				Tree:   cfg,
-			}
+			c, err := New(
+				WithLogger(logger),
+				WithConfigSource(toml.FromString(tc.config)),
+				WithUseLegacyConfig(true),
+				WithRuntimeType(""),
+			)
+			require.NoError(t, err)
 
 			err = c.AddRuntime("test", "/usr/bin/test", tc.setAsDefault)
 			require.NoError(t, err)
 
-			require.EqualValues(t, expectedConfig.String(), cfg.String())
+			require.EqualValues(t, expectedConfig.String(), c.String())
 		})
 	}
 }
diff --git a/pkg/config/engine/containerd/config_v2_test.go b/pkg/config/engine/containerd/config_v2_test.go
index a9e0c3be..6304e210 100644
--- a/pkg/config/engine/containerd/config_v2_test.go
+++ b/pkg/config/engine/containerd/config_v2_test.go
@@ -46,7 +46,7 @@ func TestAddRuntime(t *testing.T) {
 					privileged_without_host_devices = false
 					runtime_engine = ""
 					runtime_root = ""
-					runtime_type = ""
+					runtime_type = "io.containerd.runc.v2"
 					[plugins."io.containerd.grpc.v1.cri".containerd.runtimes.test.options]
 						BinaryName = "/usr/bin/test"
 			`,
@@ -199,20 +199,19 @@ func TestAddRuntime(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.description, func(t *testing.T) {
-			cfg, err := toml.Load(tc.config)
-			require.NoError(t, err)
 			expectedConfig, err := toml.Load(tc.expectedConfig)
 			require.NoError(t, err)
 
-			c := &Config{
-				Logger: logger,
-				Tree:   cfg,
-			}
+			c, err := New(
+				WithLogger(logger),
+				WithConfigSource(toml.FromString(tc.config)),
+			)
+			require.NoError(t, err)
 
 			err = c.AddRuntime("test", "/usr/bin/test", tc.setAsDefault)
 			require.NoError(t, err)
 
-			require.EqualValues(t, expectedConfig.String(), cfg.String())
+			require.EqualValues(t, expectedConfig.String(), c.String())
 		})
 	}
 }
@@ -299,13 +298,13 @@ func TestGetRuntimeConfig(t *testing.T) {
 
 	for _, tc := range testCases {
 		t.Run(tc.description, func(t *testing.T) {
-			cfg, err := toml.Load(config)
+
+			c, err := New(
+				WithLogger(logger),
+				WithConfigSource(toml.FromString(config)),
+			)
 			require.NoError(t, err)
 
-			c := &Config{
-				Logger: logger,
-				Tree:   cfg,
-			}
 			rc, err := c.GetRuntimeConfig(tc.runtime)
 			require.Equal(t, tc.expectedError, err)
 			require.Equal(t, tc.expected, rc.GetBinaryPath())
diff --git a/pkg/config/engine/docker/docker.go b/pkg/config/engine/docker/docker.go
index 6ea64f06..eda700d0 100644
--- a/pkg/config/engine/docker/docker.go
+++ b/pkg/config/engine/docker/docker.go
@@ -166,3 +166,13 @@ func (c *Config) GetRuntimeConfig(name string) (engine.RuntimeConfig, error) {
 	}
 	return &dockerRuntime{}, nil
 }
+
+// String returns the string representation of the JSON config.
+func (c Config) String() string {
+	output, err := json.MarshalIndent(c, "", "    ")
+	if err != nil {
+		return fmt.Sprintf("invalid JSON: %v", err)
+	}
+
+	return string(output)
+}
diff --git a/pkg/config/toml/source-string.go b/pkg/config/toml/source-string.go
new file mode 100644
index 00000000..72d4cc6d
--- /dev/null
+++ b/pkg/config/toml/source-string.go
@@ -0,0 +1,26 @@
+/**
+# Copyright 2024 NVIDIA CORPORATION
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+**/
+
+package toml
+
+type tomlString string
+
+var _ Loader = (*tomlFile)(nil)
+
+// Load loads the contents of the specified TOML file as a map.
+func (l tomlString) Load() (*Tree, error) {
+	return Load(string(l))
+}
diff --git a/pkg/config/toml/source.go b/pkg/config/toml/source.go
index 08907764..90cae913 100644
--- a/pkg/config/toml/source.go
+++ b/pkg/config/toml/source.go
@@ -45,3 +45,12 @@ func FromCommandLine(cmds ...string) Loader {
 		args:    cmds[1:],
 	}
 }
+
+// FromString creates a TOML source for the specified contents.
+// If an empty string is passed an empty toml config is used.
+func FromString(contents string) Loader {
+	if contents == "" {
+		return Empty
+	}
+	return tomlString(contents)
+}