diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/env/LeaseAwareVaultPropertySource.java b/spring-vault-core/src/main/java/org/springframework/vault/core/env/LeaseAwareVaultPropertySource.java
index f3966293..d8bd1c18 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/env/LeaseAwareVaultPropertySource.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/env/LeaseAwareVaultPropertySource.java
@@ -60,7 +60,7 @@ public class LeaseAwareVaultPropertySource
 
 	private final RequestedSecret requestedSecret;
 
-	private final Map<String, String> properties = new ConcurrentHashMap<>();
+	private final Map<String, Object> properties = new ConcurrentHashMap<>();
 
 	private final PropertyTransformer propertyTransformer;
 
@@ -174,7 +174,7 @@ public class LeaseAwareVaultPropertySource
 	 * @param properties reference to property storage of this property source.
 	 */
 	protected void handleLeaseEvent(SecretLeaseEvent leaseEvent,
-			Map<String, String> properties) {
+			Map<String, Object> properties) {
 
 		if (leaseEvent.getSource() != getRequestedSecret()) {
 			return;
@@ -189,7 +189,7 @@ public class LeaseAwareVaultPropertySource
 		if (leaseEvent instanceof SecretLeaseCreatedEvent) {
 
 			SecretLeaseCreatedEvent created = (SecretLeaseCreatedEvent) leaseEvent;
-			properties.putAll(doTransformProperties(toStringMap(created.getSecrets())));
+			properties.putAll(doTransformProperties(flattenMap(created.getSecrets())));
 		}
 	}
 
@@ -199,18 +199,32 @@ public class LeaseAwareVaultPropertySource
 	 * @param properties must not be {@literal null}.
 	 * @return the transformed properties.
 	 */
-	protected Map<String, String> doTransformProperties(Map<String, String> properties) {
+	protected Map<String, Object> doTransformProperties(Map<String, Object> properties) {
 		return this.propertyTransformer.transformProperties(properties);
 	}
 
 	/**
-	 * Utility method converting a {@code String/Object} map to a {@code String/String}
-	 * map.
+	 * Utility method converting a {@code String/Object} map to a flat
+	 * {@code String/String} map. Nested objects are represented with property paths.
 	 *
 	 * @param data the map
 	 * @return the flattened map.
+	 * @deprecated since 2.0, use {@link #flattenMap(Map)} to retain JSON data types.
 	 */
+	@Deprecated
 	protected Map<String, String> toStringMap(Map<String, Object> data) {
+		return JsonMapFlattener.flattenToStringMap(data);
+	}
+
+	/**
+	 * Utility method converting a {@code String/Object} map to a flat
+	 * {@code String/Object} map. Nested objects are represented with property path keys.
+	 *
+	 * @param data the map
+	 * @return the flattened map.
+	 * @since 2.0
+	 */
+	protected Map<String, Object> flattenMap(Map<String, Object> data) {
 		return JsonMapFlattener.flatten(data);
 	}
 }
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/env/VaultPropertySource.java b/spring-vault-core/src/main/java/org/springframework/vault/core/env/VaultPropertySource.java
index 8788c835..2c46bc50 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/env/VaultPropertySource.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/env/VaultPropertySource.java
@@ -50,7 +50,7 @@ public class VaultPropertySource extends EnumerablePropertySource<VaultOperation
 
 	private final String path;
 
-	private final Map<String, String> properties = new LinkedHashMap<>();
+	private final Map<String, Object> properties = new LinkedHashMap<>();
 
 	private final PropertyTransformer propertyTransformer;
 
@@ -122,7 +122,7 @@ public class VaultPropertySource extends EnumerablePropertySource<VaultOperation
 				logger.debug(String.format("Fetching properties from Vault at %s", path));
 			}
 
-			Map<String, String> properties = doGetProperties(path);
+			Map<String, Object> properties = doGetProperties(path);
 
 			if (properties != null) {
 				this.properties.putAll(doTransformProperties(properties));
@@ -154,7 +154,7 @@ public class VaultPropertySource extends EnumerablePropertySource<VaultOperation
 	 * @throws VaultException on problems retrieving properties
 	 */
 	@Nullable
-	protected Map<String, String> doGetProperties(String path) throws VaultException {
+	protected Map<String, Object> doGetProperties(String path) throws VaultException {
 
 		VaultResponse vaultResponse = this.source.read(path);
 
@@ -166,7 +166,7 @@ public class VaultPropertySource extends EnumerablePropertySource<VaultOperation
 			return null;
 		}
 
-		return toStringMap(vaultResponse.getData());
+		return flattenMap(vaultResponse.getData());
 	}
 
 	/**
@@ -175,18 +175,32 @@ public class VaultPropertySource extends EnumerablePropertySource<VaultOperation
 	 * @param properties must not be {@literal null}.
 	 * @return the transformed properties.
 	 */
-	protected Map<String, String> doTransformProperties(Map<String, String> properties) {
+	protected Map<String, Object> doTransformProperties(Map<String, Object> properties) {
 		return this.propertyTransformer.transformProperties(properties);
 	}
 
 	/**
-	 * Utility method converting a {@code String/Object} map to a {@code String/String}
-	 * map.
+	 * Utility method converting a {@code String/Object} map to a flat
+	 * {@code String/String} map.
 	 *
 	 * @param data the map
 	 * @return the flattened map.
+	 * @deprecated since 2.0, use {@link #flattenMap(Map)} to retain JSON data types.
 	 */
+	@Deprecated
 	protected Map<String, String> toStringMap(Map<String, Object> data) {
+		return JsonMapFlattener.flattenToStringMap(data);
+	}
+
+	/**
+	 * Utility method converting a {@code String/Object} map to a flat
+	 * {@code String/Object} map. Nested objects are represented with property path keys.
+	 *
+	 * @param data the map
+	 * @return the flattened map.
+	 * @since 2.0
+	 */
+	protected Map<String, Object> flattenMap(Map<String, Object> data) {
 		return JsonMapFlattener.flatten(data);
 	}
 }
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformer.java b/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformer.java
index e561441d..f101d9df 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformer.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformer.java
@@ -38,7 +38,7 @@ public interface PropertyTransformer {
 	 * @param input must not be {@literal null}.
 	 * @return transformed properties.
 	 */
-	Map<String, String> transformProperties(Map<String, String> input);
+	Map<String, Object> transformProperties(Map<String, Object> input);
 
 	/**
 	 * Return a composed transformer function that first applies this filter, and then
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformers.java b/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformers.java
index 2f7ea1ff..d0f814ba 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformers.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/util/PropertyTransformers.java
@@ -66,10 +66,9 @@ public abstract class PropertyTransformers {
 			return new PropertyTransformerSupport() {
 
 				@Override
-				public Map<String, String> transformProperties(
-						Map<String, String> input) {
+				public Map<String, Object> transformProperties(Map<String, Object> input) {
 
-					Map<String, String> processed = that.transformProperties(input);
+					Map<String, Object> processed = that.transformProperties(input);
 					return after.transformProperties(processed);
 				}
 			};
@@ -95,7 +94,7 @@ public abstract class PropertyTransformers {
 		}
 
 		@Override
-		public Map<String, String> transformProperties(Map<String, String> input) {
+		public Map<String, Object> transformProperties(Map<String, Object> input) {
 			return input;
 		}
 	}
@@ -118,12 +117,12 @@ public abstract class PropertyTransformers {
 		}
 
 		@Override
-		public Map<String, String> transformProperties(Map<String, String> input) {
+		public Map<String, Object> transformProperties(Map<String, Object> input) {
 
-			Map<String, String> target = new LinkedHashMap<>(input.size(),
+			Map<String, Object> target = new LinkedHashMap<>(input.size(),
 					1);
 
-			for (Entry<String, String> entry : input.entrySet()) {
+			for (Entry<String, Object> entry : input.entrySet()) {
 
 				if (entry.getValue() == null) {
 					continue;
@@ -163,12 +162,12 @@ public abstract class PropertyTransformers {
 		}
 
 		@Override
-		public Map<String, String> transformProperties(Map<String, String> input) {
+		public Map<String, Object> transformProperties(Map<String, Object> input) {
 
-			Map<String, String> target = new LinkedHashMap<>(input.size(),
+			Map<String, Object> target = new LinkedHashMap<>(input.size(),
 					1);
 
-			for (Entry<String, String> entry : input.entrySet()) {
+			for (Entry<String, Object> entry : input.entrySet()) {
 				target.put(propertyNamePrefix + entry.getKey(), entry.getValue());
 			}
 
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/support/JsonMapFlattener.java b/spring-vault-core/src/main/java/org/springframework/vault/support/JsonMapFlattener.java
index fe88b6df..990a4b2a 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/support/JsonMapFlattener.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/support/JsonMapFlattener.java
@@ -19,6 +19,8 @@ import java.util.Iterator;
 import java.util.LinkedHashMap;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.function.Function;
+import java.util.function.UnaryOperator;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
@@ -37,20 +39,17 @@ import org.springframework.util.StringUtils;
  * <p>
  * Input:
  *
- * <pre>
- * <code>
- *     {"key": {"nested: "value"}, "another.key": ["one", "two"] }
- * </code>
+ * <pre class="code">
+ *     {"key": {"nested: 1}, "another.key": ["one", "two"] }
  * </pre>
  *
  * <br>
  * Result
  *
- * <pre>
- * <code> key.nested=value
+ * <pre class="code">
+ *  key.nested=1
  *  another.key[0]=one
  *  another.key[1]=two
- * </code>
  * </pre>
  *
  * @author Mark Paluch
@@ -67,19 +66,42 @@ public abstract class JsonMapFlattener {
 	 * @param inputMap must not be {@literal null}.
 	 * @return the resulting {@link Map}.
 	 */
-	public static Map<String, String> flatten(Map<String, ? extends Object> inputMap) {
+	public static Map<String, Object> flatten(Map<String, ? extends Object> inputMap) {
+
+		Assert.notNull(inputMap, "Input Map must not be null");
+
+		Map<String, Object> resultMap = new LinkedHashMap<>();
+
+		doFlatten("", inputMap.entrySet().iterator(), resultMap, UnaryOperator.identity());
+
+		return resultMap;
+	}
+
+	/**
+	 * Flatten a hierarchical {@link Map} into a flat {@link Map} with key names using
+	 * property dot notation.
+	 *
+	 * @param inputMap must not be {@literal null}.
+	 * @return the resulting {@link Map}.
+	 * @since 2.0
+	 */
+	public static Map<String, String> flattenToStringMap(
+			Map<String, ? extends Object> inputMap) {
 
 		Assert.notNull(inputMap, "Input Map must not be null");
 
 		Map<String, String> resultMap = new LinkedHashMap<>();
 
-		doFlatten("", inputMap.entrySet().iterator(), resultMap);
+		doFlatten("", inputMap.entrySet().iterator(), resultMap, it -> it == null ? null
+				: it.toString());
 
 		return resultMap;
 	}
 
 	private static void doFlatten(String propertyPrefix,
-			Iterator<? extends Entry<String, ?>> inputMap, Map<String, String> resultMap) {
+			Iterator<? extends Entry<String, ?>> inputMap,
+			Map<String, ? extends Object> resultMap,
+			Function<Object, Object> valueTransformer) {
 
 		if (StringUtils.hasText(propertyPrefix)) {
 			propertyPrefix = propertyPrefix + ".";
@@ -89,35 +111,38 @@ public abstract class JsonMapFlattener {
 
 			Entry<String, ? extends Object> entry = inputMap.next();
 			flattenElement(propertyPrefix.concat(entry.getKey()), entry.getValue(),
-					resultMap);
+					resultMap, valueTransformer);
 		}
 	}
 
 	@SuppressWarnings("unchecked")
 	private static void flattenElement(String propertyPrefix, @Nullable Object source,
-			Map<String, String> resultMap) {
+			Map<String, ?> resultMap, Function<Object, Object> valueTransformer) {
 
 		if (source instanceof Iterable) {
-			flattenCollection(propertyPrefix, (Iterable<Object>) source, resultMap);
+			flattenCollection(propertyPrefix, (Iterable<Object>) source, resultMap,
+					valueTransformer);
 			return;
 		}
 
 		if (source instanceof Map) {
 			doFlatten(propertyPrefix, ((Map<String, ?>) source).entrySet().iterator(),
-					resultMap);
+					resultMap, valueTransformer);
 			return;
 		}
 
-		resultMap.put(propertyPrefix, source == null ? null : source.toString());
+		((Map) resultMap).put(propertyPrefix, valueTransformer.apply(source));
 	}
 
 	private static void flattenCollection(String propertyPrefix,
-			Iterable<Object> iterable, Map<String, String> resultMap) {
+			Iterable<Object> iterable, Map<String, ?> resultMap,
+			Function<Object, Object> valueTransformer) {
 
 		int counter = 0;
 
 		for (Object element : iterable) {
-			flattenElement(propertyPrefix + "[" + counter + "]", element, resultMap);
+			flattenElement(propertyPrefix + "[" + counter + "]", element, resultMap,
+					valueTransformer);
 			counter++;
 		}
 	}
diff --git a/spring-vault-core/src/test/java/org/springframework/vault/core/env/VaultPropertySourceUnitTests.java b/spring-vault-core/src/test/java/org/springframework/vault/core/env/VaultPropertySourceUnitTests.java
index e3d4fa4a..7c11901f 100644
--- a/spring-vault-core/src/test/java/org/springframework/vault/core/env/VaultPropertySourceUnitTests.java
+++ b/spring-vault-core/src/test/java/org/springframework/vault/core/env/VaultPropertySourceUnitTests.java
@@ -63,7 +63,7 @@ public class VaultPropertySourceUnitTests {
 				vaultTemplate, "secret/myapp", PropertyTransformers.noop());
 
 		assertThat(vaultPropertySource.getProperty("key")).isEqualTo("value");
-		assertThat(vaultPropertySource.getProperty("integer")).isEqualTo("1");
+		assertThat(vaultPropertySource.getProperty("integer")).isEqualTo(1);
 		assertThat(vaultPropertySource.getProperty("complex.key")).isEqualTo("value");
 		assertThat(vaultPropertySource.getProperty("empty")).isNull();
 		assertThat(vaultPropertySource.containsProperty("empty")).isFalse();
@@ -82,7 +82,7 @@ public class VaultPropertySourceUnitTests {
 		assertThat(vaultPropertySource.containsProperty("key")).isFalse();
 		assertThat(vaultPropertySource.getProperty("database.key")).isEqualTo("value");
 		assertThat(vaultPropertySource.getProperty("key")).isNull();
-		assertThat(vaultPropertySource.getProperty("database.integer")).isEqualTo("1");
+		assertThat(vaultPropertySource.getProperty("database.integer")).isEqualTo(1);
 		assertThat(vaultPropertySource.getProperty("database.complex.key")).isEqualTo(
 				"value");
 	}
diff --git a/spring-vault-core/src/test/java/org/springframework/vault/core/util/PropertyTransformersUnitTests.java b/spring-vault-core/src/test/java/org/springframework/vault/core/util/PropertyTransformersUnitTests.java
index bcf72ff9..202b1a47 100644
--- a/spring-vault-core/src/test/java/org/springframework/vault/core/util/PropertyTransformersUnitTests.java
+++ b/spring-vault-core/src/test/java/org/springframework/vault/core/util/PropertyTransformersUnitTests.java
@@ -27,7 +27,7 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 public class PropertyTransformersUnitTests {
 
-	Map<String, String> properties = Collections.singletonMap("key", "value");
+	Map<String, Object> properties = Collections.singletonMap("key", "value");
 
 	@Test
 	public void propertyNamePrefix() {
diff --git a/spring-vault-core/src/test/java/org/springframework/vault/support/JsonMapFlattenerUnitTests.java b/spring-vault-core/src/test/java/org/springframework/vault/support/JsonMapFlattenerUnitTests.java
index bd43a645..4a79c06f 100644
--- a/spring-vault-core/src/test/java/org/springframework/vault/support/JsonMapFlattenerUnitTests.java
+++ b/spring-vault-core/src/test/java/org/springframework/vault/support/JsonMapFlattenerUnitTests.java
@@ -34,9 +34,9 @@ public class JsonMapFlattenerUnitTests {
 	private static final ObjectMapper objectMapper = new ObjectMapper();
 
 	@Test
-	public void shouldPreserveFlatMap() throws Exception {
+	public void shouldPreserveFlatMap() {
 
-		Map<String, String> result = JsonMapFlattener.flatten(Collections.singletonMap(
+		Map<String, Object> result = JsonMapFlattener.flatten(Collections.singletonMap(
 				"key", "value"));
 		assertThat(result).containsEntry("key", "value");
 	}
@@ -45,10 +45,10 @@ public class JsonMapFlattenerUnitTests {
 	public void shouldFlattenNestedObject() throws Exception {
 
 		Map<String, Object> map = objectMapper.readValue(
-				"{\"key\": { \"nested\":\"value\"} }", Map.class);
-		Map<String, String> result = JsonMapFlattener.flatten(map);
+				"{\"key\": { \"nested\":true} }", Map.class);
+		Map<String, Object> result = JsonMapFlattener.flatten(map);
 
-		assertThat(result).containsEntry("key.nested", "value");
+		assertThat(result).containsEntry("key.nested", true);
 	}
 
 	@Test
@@ -56,7 +56,7 @@ public class JsonMapFlattenerUnitTests {
 
 		Map<String, Object> map = objectMapper.readValue(
 				"{\"key\": { \"nested\": {\"anotherLevel\": \"value\"} } }", Map.class);
-		Map<String, String> result = JsonMapFlattener.flatten(map);
+		Map<String, Object> result = JsonMapFlattener.flatten(map);
 
 		assertThat(result).containsEntry("key.nested.anotherLevel", "value");
 	}
@@ -67,7 +67,7 @@ public class JsonMapFlattenerUnitTests {
 		Map<String, Object> map = objectMapper.readValue(
 				"{\"key\": [\"one\", \"two\"], \"dotted.key\": [\"one\", \"two\"] }",
 				Map.class);
-		Map<String, String> result = JsonMapFlattener.flatten(map);
+		Map<String, Object> result = JsonMapFlattener.flatten(map);
 
 		assertThat(result).containsEntry("key[0]", "one").containsEntry("key[1]", "two");
 		assertThat(result).containsEntry("dotted.key[0]", "one").containsEntry(
@@ -80,7 +80,7 @@ public class JsonMapFlattenerUnitTests {
 		Map<String, Object> map = objectMapper.readValue(
 				"{\"key\": [{ \"nested\":\"value\"}, { \"nested\":\"other-value\"}] }",
 				Map.class);
-		Map<String, String> result = JsonMapFlattener.flatten(map);
+		Map<String, Object> result = JsonMapFlattener.flatten(map);
 
 		assertThat(result).containsEntry("key[0].nested", "value").containsEntry(
 				"key[1].nested", "other-value");
@@ -93,7 +93,7 @@ public class JsonMapFlattenerUnitTests {
 				.readValue(
 						"{\"key\": { \"level1\": [{ \"nested\":\"value\"}, { \"nested\":\"other-value\"}]} }",
 						Map.class);
-		Map<String, String> result = JsonMapFlattener.flatten(map);
+		Map<String, Object> result = JsonMapFlattener.flatten(map);
 
 		assertThat(result).containsEntry("key.level1[0].nested", "value").containsEntry(
 				"key.level1[1].nested", "other-value");