diff --git a/.gitignore b/.gitignore
index cade38a..ca9f805 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@ node_modules/
 dist/
 .env
 dev
+.history/
diff --git a/.prettierignore b/.prettierignore
index 83ffe87..fb94fc2 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,3 +1,4 @@
 dist/
 *.yml
 README.md
+.history/
diff --git a/README.md b/README.md
index ae2c692..91e1309 100644
--- a/README.md
+++ b/README.md
@@ -107,8 +107,8 @@ e.i. `https://<chaos-proxy>/api/v2/manifests/hls/proxy-master.m3u8?url=<some_url
 Across all corruptions, there are 3 ways to target a segment in a playlist for corruption.
 
 1. `i`: The segment's list index in any Media Playlist, with HLS segments starting at 0 and MPEG-DASH segments starting at 1. For a Media Playlist with 12 segments, `i`=11, would target the last segment for HLS and `i`=12, would target the last segment for MPEG-DASH.
-2. `sq`: The segment's Media Sequence Number for HLS, or the "$Number$" or "$Time$" part of a segment URL for DASH. For an HLS Media Playlist with 12 segments, and where `#EXT-X-MEDIA-SEQUENCE` is 100, `sq`=111 would target the last segment. When corrupting a live HLS stream it is recommended to target with `rsq`.
-3. `rsq`: A relative sequence number, counted from where the live stream is currently at when requesting manifest. Can also use a negative integer, which enables counting backwards from the end of the manifest instead. (**HLS SUPPORTED ONLY IN STATEFUL MODE**)
+2. `sq`: The segment's Media Sequence Number for HLS, or the "$Number$" or "$Time$" part of a segment URL for DASH. For an HLS Media Playlist with 12 segments, and where `#EXT-X-MEDIA-SEQUENCE` is 100, `sq`=111 would target the last segment. When corrupting a live HLS or DASH stream it is recommended to target with `rsq`.
+3. `rsq`: A relative sequence number, counted from where the live stream is currently at when requesting manifest. Can also use a negative integer, which enables counting backwards from the end of the manifest instead. (**SUPPORTED ONLY IN STATEFUL MODE FOR BOTH HLS AND DASH**)
 
 Below are configuration JSON object templates for the currently supported corruptions. A query should have its value be an array consisting of any one of these 3 types of items:
 
@@ -258,6 +258,11 @@ https://<chaos-proxy>/api/v2/manifests/dash/proxy-master.mpd?url=https://livesim
 https://<chaos-proxy>/api/v2/manifests/dash/proxy-master.mpd?url=https://f53accc45b7aded64ed8085068f31881.egress.mediapackage-vod.eu-north-1.amazonaws.com/out/v1/1c63bf88e2664639a6c293b4d055e6bb/64651f16da554640930b7ce2cd9f758b/66d211307b7d43d3bd515a3bfb654e1c/manifest.mpd&throttle=[{i:*,rate:10000}]
 ```
 
+7. LIVE: Example of MPEG-DASH with a segment delay of 5000ms on segment with relative sequence number equal to 2:
+
+```
+https://<chaos-proxy>/api/v2/manifests/dash/proxy-master.mpd?url=https://livesim.dashif.org/livesim/testpic_2s/Manifest.mpd&delay=[{rsq:2, ms:5000}]
+```
 ## Development Environment
 
 To deploy and update development environment create and push a tag with the suffix `-dev`, for example `my-feat-test-dev`. If you run `npm run deploy:dev` it will automatically create a tag based on git revision with the `-dev` suffix and push it.
diff --git a/package-lock.json b/package-lock.json
index 011f5b0..a233a32 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -48,7 +48,7 @@
         "eslint-plugin-prettier": "^4.2.1",
         "husky": "^2.7.0",
         "lint-staged": "^12.3.4",
-        "prettier": "^2.8.7",
+        "prettier": "2.8.8",
         "ts-jest": "^27.1.3",
         "tsc-watch": "^5.0.3",
         "typescript": "^3.7.3"
@@ -10988,9 +10988,9 @@
       }
     },
     "node_modules/prettier": {
-      "version": "2.8.7",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.7.tgz",
-      "integrity": "sha512-yPngTo3aXUUmyuTjeTUT75txrf+aMh9FiD7q9ZE/i6r0bPb22g4FsE6Y338PQX1bmfy08i9QQCB7/rcUAVntfw==",
+      "version": "2.8.8",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.8.tgz",
+      "integrity": "sha512-tdN8qQGvNjw4CHbY+XXk0JgCXn9QiF21a55rBe5LJAU+kDyC4WQn4+awm2Xfk2lQMk5fKup9XgzTZtGkjBdP9Q==",
       "dev": true,
       "bin": {
         "prettier": "bin-prettier.js"
@@ -21315,9 +21315,9 @@
       "integrity": "sha1-IZMqVJ9eUv/ZqCf1cOBL5iqX2lQ="
     },
     "prettier": {
-      "version": "2.8.7",
-      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.7.tgz",
-      "integrity": "sha512-yPngTo3aXUUmyuTjeTUT75txrf+aMh9FiD7q9ZE/i6r0bPb22g4FsE6Y338PQX1bmfy08i9QQCB7/rcUAVntfw==",
+      "version": "2.8.8",
+      "resolved": "https://registry.npmjs.org/prettier/-/prettier-2.8.8.tgz",
+      "integrity": "sha512-tdN8qQGvNjw4CHbY+XXk0JgCXn9QiF21a55rBe5LJAU+kDyC4WQn4+awm2Xfk2lQMk5fKup9XgzTZtGkjBdP9Q==",
       "dev": true
     },
     "prettier-linter-helpers": {
diff --git a/package.json b/package.json
index 0fc1b80..c559082 100644
--- a/package.json
+++ b/package.json
@@ -55,7 +55,7 @@
     "eslint-plugin-prettier": "^4.2.1",
     "husky": "^2.7.0",
     "lint-staged": "^12.3.4",
-    "prettier": "^2.8.7",
+    "prettier": "2.8.8",
     "ts-jest": "^27.1.3",
     "tsc-watch": "^5.0.3",
     "typescript": "^3.7.3"
diff --git a/src/manifests/handlers/dash/segment.ts b/src/manifests/handlers/dash/segment.ts
index 59b60d1..7d4b279 100644
--- a/src/manifests/handlers/dash/segment.ts
+++ b/src/manifests/handlers/dash/segment.ts
@@ -4,7 +4,9 @@ import {
   composeALBEvent,
   generateErrorResponse,
   isValidUrl,
-  segmentUrlParamString
+  segmentUrlParamString,
+  STATEFUL,
+  newState
 } from '../../../shared/utils';
 import delaySCC from '../../utils/corruptions/delay';
 import statusCodeSCC from '../../utils/corruptions/statusCode';
@@ -56,6 +58,10 @@ export default async function dashSegmentHandler(
     }
     const reqSegmentIndexInt = parseInt(reqSegmentIndexOrTimeStr);
 
+    const stateKey = STATEFUL
+      ? newState({ initialSequenceNumber: undefined })
+      : undefined;
+
     // Replace RepresentationID in url if present
     if (representationIdStr) {
       segmentUrl = segmentUrl.replace(
@@ -85,7 +91,8 @@ export default async function dashSegmentHandler(
     const dashUtils = dashManifestUtils();
     const mergedMaps = dashUtils.utils.mergeMap(
       reqSegmentIndexInt,
-      allMutations
+      allMutations,
+      stateKey
     );
     const segUrl = new URL(segmentUrl);
     const cleanSegUrl = segUrl.origin + segUrl.pathname;
diff --git a/src/manifests/utils/configs.test.ts b/src/manifests/utils/configs.test.ts
index d145658..9e8b558 100644
--- a/src/manifests/utils/configs.test.ts
+++ b/src/manifests/utils/configs.test.ts
@@ -257,6 +257,60 @@ describe('configs', () => {
         );
       });
     });
+
+    describe('not in stateful mode', () => {
+      let nonStatefulConfig;
+      beforeAll(() => {
+        delete process.env.STATEFUL; // Ensure STATEFUL is not set
+        nonStatefulConfig = require('./configs');
+      });
+
+      it('should handle DASH mode without stateful', () => {
+        // Arrange
+        const configs = nonStatefulConfig.corruptorConfigUtils(
+          new URLSearchParams(
+            'statusCode=[{rsq:15,code:400}]&throttle=[{sq:15,rate:1000}]'
+          )
+        );
+
+        configs.register(statusCodeConfig).register(throttleConfig);
+
+        // Act
+
+        const [err, actual] = configs.getAllManifestConfigs(0, true);
+
+        // Assert
+        expect(err).toEqual({
+          status: 400,
+          message:
+            'Relative sequence numbers on DASH are only supported when proxy is running in stateful mode'
+        });
+        expect(actual).toBeNull();
+      });
+
+      it('should handle HLS mode without stateful', () => {
+        // Arrange
+        const configs = nonStatefulConfig.corruptorConfigUtils(
+          new URLSearchParams(
+            'statusCode=[{rsq:15,code:400}]&throttle=[{sq:15,rate:1000}]'
+          )
+        );
+
+        configs.register(statusCodeConfig).register(throttleConfig);
+
+        // Act
+
+        const [err, actual] = configs.getAllManifestConfigs(0, false);
+
+        // Assert
+        expect(err).toEqual({
+          status: 400,
+          message:
+            'Relative sequence numbers on HLS are only supported when proxy is running in stateful mode'
+        });
+        expect(actual).toBeNull();
+      });
+    });
   });
 
   describe('getAllSegmentConfigs', () => {
diff --git a/src/manifests/utils/configs.ts b/src/manifests/utils/configs.ts
index bf678bb..8c0aa60 100644
--- a/src/manifests/utils/configs.ts
+++ b/src/manifests/utils/configs.ts
@@ -167,6 +167,16 @@ export const corruptorConfigUtils = function (
               null
             ];
           }
+          if (hasRelativeSequences && !STATEFUL && isDash) {
+            return [
+              {
+                status: 400,
+                message:
+                  'Relative sequence numbers on DASH are only supported when proxy is running in stateful mode'
+              },
+              null
+            ];
+          }
 
           // If bitrate is set, filter out segments that doesn't match
           params = params.filter(
diff --git a/src/manifests/utils/dashManifestUtils.test.ts b/src/manifests/utils/dashManifestUtils.test.ts
index f136674..59c1496 100644
--- a/src/manifests/utils/dashManifestUtils.test.ts
+++ b/src/manifests/utils/dashManifestUtils.test.ts
@@ -157,7 +157,8 @@ describe('utils.mergeMap', () => {
     // Act
     const actual = dashManifestUtils().utils.mergeMap(
       mockReqSegIndex,
-      mockAllCorruptions
+      mockAllCorruptions,
+      undefined
     );
     const expected = new Map<string, CorruptorConfig>()
       .set('a', { fields: { ms: 100 } })
@@ -191,7 +192,11 @@ describe('utils.mergeMap', () => {
     const actual: CorruptorConfigMap[] = [];
     for (let segIdx = 0; segIdx < 3; segIdx++) {
       actual.push(
-        dashManifestUtils().utils.mergeMap(segIdx, mockAllCorruptions)
+        dashManifestUtils().utils.mergeMap(
+          segIdx,
+          mockAllCorruptions,
+          undefined
+        )
       );
     }
 
@@ -226,7 +231,11 @@ describe('utils.mergeMap', () => {
     const actual: CorruptorConfigMap[] = [];
     for (let segIdx = 0; segIdx < 3; segIdx++) {
       actual.push(
-        dashManifestUtils().utils.mergeMap(segIdx, mockAllCorruptions)
+        dashManifestUtils().utils.mergeMap(
+          segIdx,
+          mockAllCorruptions,
+          undefined
+        )
       );
     }
     const expected = [
@@ -252,7 +261,8 @@ describe('utils.mergeMap', () => {
     // Act
     const actual = dashManifestUtils().utils.mergeMap(
       mockReqSegIndex,
-      mockAllCorruptions
+      mockAllCorruptions,
+      undefined
     );
     const expected = new Map<string, CorruptorConfig>().set('a', {
       fields: {}
diff --git a/src/manifests/utils/dashManifestUtils.ts b/src/manifests/utils/dashManifestUtils.ts
index 8dee572..99b67b4 100644
--- a/src/manifests/utils/dashManifestUtils.ts
+++ b/src/manifests/utils/dashManifestUtils.ts
@@ -7,7 +7,8 @@ import { URLSearchParams } from 'url';
 interface DASHManifestUtils {
   mergeMap: (
     segmentListSize: number,
-    configsMap: IndexedCorruptorConfigMap
+    configsMap: IndexedCorruptorConfigMap,
+    stateKey: string | undefined
   ) => CorruptorConfigMap;
 }
 
diff --git a/src/shared/utils.ts b/src/shared/utils.ts
index 923d8ef..6fe93fe 100644
--- a/src/shared/utils.ts
+++ b/src/shared/utils.ts
@@ -14,7 +14,7 @@ import {
   FastifyInstance
 } from 'fastify';
 import { addSSMUrlParametersToUrl } from './aws.utils';
-
+import { URLSearchParams } from 'url';
 import dotenv from 'dotenv';
 import { Readable } from 'stream';
 import NodeCache from 'node-cache';