diff --git a/tsp-typescript-client/fixtures/tsp-client/fetch-generic-xy-0.json b/tsp-typescript-client/fixtures/tsp-client/fetch-generic-xy-0.json
index 1345492..e0fa467 100644
--- a/tsp-typescript-client/fixtures/tsp-client/fetch-generic-xy-0.json
+++ b/tsp-typescript-client/fixtures/tsp-client/fetch-generic-xy-0.json
@@ -6,26 +6,26 @@
         "seriesId": 3,
         "seriesName": "15652",
         "xValues": [
-          [
-            0,
-            604229397
-          ],
-          [
-            604229398,
-            1208458795
-          ],
-          [
-            1208458796,
-            1812688193
-          ],
-          [
-            1812688194,
-            2416917590
-          ],
-          [
-            2416917591,
-            3021146988
-          ]
+          {
+            "start": 0,
+            "end": 604229397
+          },
+          {
+            "start": 604229398,
+            "end": 1208458795
+          },
+          {
+            "start": 1208458796,
+            "end": 1812688193
+          },
+          {
+            "start": 1812688194,
+            "end": 2416917590
+          },
+          {
+            "start": 2416917591,
+            "end": 3021146988
+          }
         ],
         "yValues": [
           3.0,
@@ -61,26 +61,26 @@
         "seriesId": 4,
         "seriesName": "15653",
         "xValues": [
-          [
-            0,
-            604229397
-          ],
-          [
-            604229398,
-            1208458795
-          ],
-          [
-            1208458796,
-            1812688193
-          ],
-          [
-            1812688194,
-            2416917590
-          ],
-          [
-            2416917591,
-            3021146988
-          ]
+          {
+            "start": 0,
+            "end": 604229397
+          },
+          {
+            "start": 604229398,
+            "end": 1208458795
+          },
+          {
+            "start": 1208458796,
+            "end": 1812688193
+          },
+          {
+            "start": 1812688194,
+            "end": 2416917590
+          },
+          {
+            "start": 2416917591,
+            "end": 3021146988
+          }
         ],
         "yValues": [
           3.0,
@@ -116,26 +116,26 @@
         "seriesId": 2,
         "seriesName": "15646",
         "xValues": [
-          [
-            0,
-            604229397
-          ],
-          [
-            604229398,
-            1208458795
-          ],
-          [
-            1208458796,
-            1812688193
-          ],
-          [
-            1812688194,
-            2416917590
-          ],
-          [
-            2416917591,
-            3021146988
-          ]
+          {
+            "start": 0,
+            "end": 604229397
+          },
+          {
+            "start": 604229398,
+            "end": 1208458795
+          },
+          {
+            "start": 1208458796,
+            "end": 1812688193
+          },
+          {
+            "start": 1812688194,
+            "end": 2416917590
+          },
+          {
+            "start": 2416917591,
+            "end": 3021146988
+          }
         ],
         "yValues": [
           3.0,
@@ -171,26 +171,26 @@
         "seriesId": 1,
         "seriesName": "15647",
         "xValues": [
-          [
-            0,
-            604229397
-          ],
-          [
-            604229398,
-            1208458795
-          ],
-          [
-            1208458796,
-            1812688193
-          ],
-          [
-            1812688194,
-            2416917590
-          ],
-          [
-            2416917591,
-            3021146988
-          ]
+          {
+            "start": 0,
+            "end": 604229397
+          },
+          {
+            "start": 604229398,
+            "end": 1208458795
+          },
+          {
+            "start": 1208458796,
+            "end": 1812688193
+          },
+          {
+            "start": 1812688194,
+            "end": 2416917590
+          },
+          {
+            "start": 2416917591,
+            "end": 3021146988
+          }
         ],
         "yValues": [
           3.0,
diff --git a/tsp-typescript-client/src/models/sampling.ts b/tsp-typescript-client/src/models/sampling.ts
index 8946ca2..a2b5634 100644
--- a/tsp-typescript-client/src/models/sampling.ts
+++ b/tsp-typescript-client/src/models/sampling.ts
@@ -1,14 +1,25 @@
-import { toBigInt } from '../protocol/serialization';
+import { createNormalizer, toBigInt } from '../protocol/serialization';
 
-export type StartEndRange = [bigint, bigint];
+export const StartEndRange = createNormalizer<StartEndRange>({
+    start: BigInt,
+    end: BigInt,
+});
+
+/**
+ * Represents a closed interval {start, end} as an object.
+ */
+export interface StartEndRange {
+  /**
+   * Start time of the range
+   */
+  start: bigint;
+
+  /**
+   * End time of the range
+   */
+  end: bigint;
+}
 
-export const StartEndRange = (v: unknown): StartEndRange => {
-  if (!Array.isArray(v) || v.length !== 2) {
-    throw new Error('StartEndRange: expected [start,end]');
-  }
-  const [s, e] = v;
-  return [toBigInt(s as any), toBigInt(e as any)];
-};
 
 /**
  * Represent sampling on a list of timestamps.
@@ -30,8 +41,21 @@ export type RangeSampling     = StartEndRange[];
  */
 export type Sampling          = TimestampSampling | CategorySampling | RangeSampling;
 
-export const isRangeSampling = (s: Sampling): s is [bigint, bigint][] =>
-  Array.isArray(s) && Array.isArray(s[0]);
+export const isRangeSampling = (s: Sampling): s is StartEndRange[] => {
+  if (!Array.isArray(s)) {
+    return false;
+  }
+  if (s.length === 0) {
+    return true;
+  }
+  const firstElement = s[0];
+  return (
+    typeof firstElement === 'object' &&
+    firstElement !== null &&
+    'start' in firstElement &&
+    'end' in firstElement
+  );
+};
 
 export const isTimestampSampling = (s: Sampling): s is bigint[] =>
   Array.isArray(s) && typeof s[0] === 'bigint';
@@ -57,9 +81,9 @@ export const Sampling = (v: unknown): Sampling => {
     return arr.map(toBigInt) as bigint[];
   }
 
-  // ranges → array of [bigint, bigint]
-  if (Array.isArray(first) && first.length === 2) {
-    return (v as unknown[]).map(StartEndRange);
+  // Range sampling (array of {start, end} objects)
+  if (typeof first === 'object' && first !== null && 'start' in first && 'end' in first) {
+    return v.map(StartEndRange);
   }
 
   // Category sampling → strings; leave as-is
diff --git a/tsp-typescript-client/src/protocol/tsp-client.test.ts b/tsp-typescript-client/src/protocol/tsp-client.test.ts
index 098cc67..daa9430 100644
--- a/tsp-typescript-client/src/protocol/tsp-client.test.ts
+++ b/tsp-typescript-client/src/protocol/tsp-client.test.ts
@@ -7,6 +7,7 @@ import { DataType } from '../models/data-type';
 import { ConfigurationParameterDescriptor } from '../models/configuration-source';
 import { QueryHelper } from '../models/query/query-helper';
 import { isAxisDomainCategorical, isAxisDomainRange } from '../models/axis-domain';
+import { StartEndRange } from '../models/sampling';
 
 describe('HttpTspClient Deserialization', () => {
 
@@ -372,12 +373,16 @@ describe('HttpTspClient Deserialization', () => {
       expect(serie.xValues).toHaveLength(5);
       expect(serie.yValues).toHaveLength(5);
       for (const xValue of serie.xValues) {
-        if (Array.isArray(xValue) && xValue.length === 2) {
-          const [start, end] = xValue;
-          expect(typeof start).toBe('bigint');
-          expect(typeof end).toBe('bigint');
+        if (
+          typeof xValue === 'object' &&
+          xValue !== null &&
+          !Array.isArray(xValue)
+        ) {
+          const rangeObject = xValue as StartEndRange;
+          expect(typeof rangeObject.start).toBe('bigint');
+          expect(typeof rangeObject.end).toBe('bigint');
         } else {
-          fail('xValues is not RangeSampling ([start,end] tuple)');
+          throw new Error('xValue is not a valid StartEndRange object ({start, end})');
         }
       }