diff --git a/README.md b/README.md
index 30698f6..e9188b1 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,7 @@ Each secret should expose a key with the same name so it becomes a file in
 - `pr-sandbox-pr-installation-id`
 - `pr-sandbox-cluster-installation-id`
 - `pr-sandbox-mysql-connection-string`
+- `pr-sandbox-redis-connection-string`
 - `pr-sandbox-argocd-webhook-auth`
 - `pr-sandbox-argocd-readonly-user-password`
 - `pr-sandbox-extra-configs`
diff --git a/app/handlers.py b/app/handlers.py
index 97e6160..66cfece 100644
--- a/app/handlers.py
+++ b/app/handlers.py
@@ -5,6 +5,7 @@
 import logging
 from fastapi import Depends, APIRouter, Header, BackgroundTasks
 from fastapi.responses import PlainTextResponse
+from redis import Redis
 from typing import Annotated
 import uuid
 
@@ -20,13 +21,20 @@
 from app.helpers.constants import GithubActionTypes, GithubEventTypes, CheckRunStatus
 from app.helpers.db_utils import SessionDep
 from app.helpers.exceptions import ActiveCheckrunNotFoundException, DBOperationException
-from app.helpers.validations import validate_signature, validate_request, validate_auth
+from app.helpers.utils import get_secret
+from app.helpers.validations import (
+    validate_signature,
+    validate_request,
+    validate_auth,
+    validate_request_not_duplicate,
+)
 from app.models.request_models import (
     GithubWebhookRequest,
     GithubWebhookHeader,
     ArgoWebhookRequest,
 )
 
+redis_client = Redis.from_url(get_secret("pr-sandbox-redis-connection-string"))
 logger = logging.getLogger(__name__)
 
 github_webhook_router = APIRouter(
@@ -181,6 +189,7 @@ def github_handler(
     """
     logger.info(headers)
     github_event = headers.x_github_event
+    validate_request_not_duplicate(headers.x_hub_signature_256, redis_client)
     validate_request(github_event, request)
     handle_github_webhook(github_event, request, db_session, background_tasks)
     return {
diff --git a/app/helpers/constants.py b/app/helpers/constants.py
index eecf461..624af43 100644
--- a/app/helpers/constants.py
+++ b/app/helpers/constants.py
@@ -318,4 +318,4 @@ class ArgoCDSyncStatus(StrEnum):
 
 PR_SANDBOX_NAME_PATTERN = r"pr-\d*-[0-9a-f]{6}"
 
-DEDUPLICATION_TTL = 300
+DEDUPLICATION_TTL = 30
diff --git a/app/helpers/validations.py b/app/helpers/validations.py
index 6a2087a..c58638a 100644
--- a/app/helpers/validations.py
+++ b/app/helpers/validations.py
@@ -6,6 +6,7 @@
 from fastapi import Request, HTTPException
 import hmac
 import hashlib
+from redis import Redis
 
 from app.helpers.conf import config
 from app.helpers.constants import (
@@ -17,6 +18,7 @@
     AUTHORIZATION_HEADER,
     AUTHORIZATION_PREFIX,
     WorkflowType,
+    DEDUPLICATION_TTL,
 )
 from app.helpers.exceptions import UnactionableRequestException
 from app.helpers.utils import get_secret
@@ -180,3 +182,11 @@ def validate_request(github_event: GithubEventTypes, request: GithubWebhookReque
         raise UnactionableRequestException("The provided installation id is invalid")
 
     _validate_request_actionable(github_event, request)
+
+
+def validate_request_not_duplicate(unique_id: str, redis_client: Redis):
+    is_unique = redis_client.set(unique_id, "1", nx=True, ex=DEDUPLICATION_TTL)
+    if not bool(is_unique):
+        raise UnactionableRequestException(
+            f"The request with id {unique_id} is not unique"
+        )
diff --git a/charts/pr-sandbox-automation/Chart.yaml b/charts/pr-sandbox-automation/Chart.yaml
index 398db10..29d8ef0 100644
--- a/charts/pr-sandbox-automation/Chart.yaml
+++ b/charts/pr-sandbox-automation/Chart.yaml
@@ -2,10 +2,14 @@ apiVersion: v2
 name: pr-sandbox-automation
 description: Automatically manage Open edX sandbox instances for PRs
 type: application
-version: 0.1.0
-appVersion: "0.1.0"
+version: 0.1.1
+appVersion: "0.2.0"
 dependencies:
   - name: mysql
     version: 9.14.1
     repository: https://charts.bitnami.com/bitnami
     condition: mysql.enabled
+  - name: redis
+    version: 24.1.3
+    repository: https://charts.bitnami.com/bitnami
+    condition: redis.enabled
diff --git a/charts/pr-sandbox-automation/templates/_helpers.tpl b/charts/pr-sandbox-automation/templates/_helpers.tpl
index 5b171e8..93e7184 100644
--- a/charts/pr-sandbox-automation/templates/_helpers.tpl
+++ b/charts/pr-sandbox-automation/templates/_helpers.tpl
@@ -39,3 +39,11 @@ app.kubernetes.io/instance: {{ .Release.Name }}
 {{- printf "%s-mysql" .Release.Name -}}
 {{- end -}}
 {{- end -}}
+
+{{- define "pr-sandbox-automation.redisHost" -}}
+{{- if .Values.redis.connectionSecret.host -}}
+{{- .Values.redis.connectionSecret.host -}}
+{{- else -}}
+{{- printf "%s-redis-master" .Release.Name -}}
+{{- end -}}
+{{- end -}}
diff --git a/charts/pr-sandbox-automation/templates/redis-connection-secret.yaml b/charts/pr-sandbox-automation/templates/redis-connection-secret.yaml
new file mode 100644
index 0000000..98be73b
--- /dev/null
+++ b/charts/pr-sandbox-automation/templates/redis-connection-secret.yaml
@@ -0,0 +1,18 @@
+{{- if and .Values.redis.enabled .Values.redis.connectionSecret.create -}}
+apiVersion: v1
+kind: Secret
+metadata:
+  name: {{ .Values.redis.connectionSecret.name }}
+  labels:
+    {{- include "pr-sandbox-automation.labels" . | nindent 4 }}
+type: Opaque
+stringData:
+  {{ .Values.redis.connectionSecret.key }}: {{- /*
+      Construct Redis connection string for the app.
+      Example: redis://:password@host:6379/0
+  */}}
+    {{- $password := required "redis.auth.password is required when redis.connectionSecret.create is true" .Values.redis.auth.password -}}
+    {{- $host := include "pr-sandbox-automation.redisHost" . -}}
+    {{- $port := .Values.redis.connectionSecret.port | default 6379 -}}
+    {{ printf "redis://:%s@%s:%d/0" $password $host $port | quote }}
+{{- end }}
diff --git a/charts/pr-sandbox-automation/values.yaml b/charts/pr-sandbox-automation/values.yaml
index 1d37eec..1feddad 100644
--- a/charts/pr-sandbox-automation/values.yaml
+++ b/charts/pr-sandbox-automation/values.yaml
@@ -86,6 +86,10 @@ secretMounts:
     items:
       - key: pr-sandbox-mysql-connection-string
         path: pr-sandbox-mysql-connection-string
+  - secretName: pr-sandbox-redis-connection-string
+    items:
+      - key: pr-sandbox-redis-connection-string
+        path: pr-sandbox-redis-connection-string
   - secretName: pr-sandbox-argocd-webhook-auth
     items:
       - key: pr-sandbox-argocd-webhook-auth
@@ -127,3 +131,27 @@ mysql:
     key: pr-sandbox-mysql-connection-string
     host: ""
     port: 3306
+
+redis:
+  enabled: false
+  architecture: standalone
+  auth:
+    enabled: true
+    password: ""
+  master:
+    persistence:
+      enabled: false
+      size: 1Gi
+    resources:
+      requests:
+        memory: "128Mi"
+        cpu: "100m"
+      limits:
+        memory: "256Mi"
+        cpu: "200m"
+  connectionSecret:
+    create: true
+    name: pr-sandbox-redis-connection-string
+    key: pr-sandbox-redis-connection-string
+    host: ""
+    port: 6379
diff --git a/dev/secrets/pr-sandbox-redis-connection-string b/dev/secrets/pr-sandbox-redis-connection-string
new file mode 100644
index 0000000..c09fc4a
--- /dev/null
+++ b/dev/secrets/pr-sandbox-redis-connection-string
@@ -0,0 +1 @@
+redis://dev-redis:6379
diff --git a/docker-compose.yml b/docker-compose.yml
index a8dfb0b..6c61434 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -9,6 +9,8 @@ secrets:
     file: dev/secrets/pr-sandbox-cluster-installation-id
   pr-sandbox-mysql-connection-string:
     file: dev/secrets/pr-sandbox-mysql-connection-string
+  pr-sandbox-redis-connection-string:
+    file: dev/secrets/pr-sandbox-redis-connection-string
   pr-sandbox-argocd-webhook-auth:
     file: dev/secrets/pr-sandbox-argocd-webhook-auth
   pr-sandbox-argocd-readonly-user-password:
@@ -30,6 +32,12 @@ services:
     volumes:
       - db_data:/var/lib/mysql
 
+  dev-redis:
+    container_name: redis-dev
+    image: redis:8.4
+    ports:
+      - "6379:6379"
+
   dev-app:
     container_name: pr-sandbox-automation-dev-app
     build:
@@ -45,6 +53,7 @@ services:
       - pr-sandbox-pr-installation-id
       - pr-sandbox-cluster-installation-id
       - pr-sandbox-mysql-connection-string
+      - pr-sandbox-redis-connection-string
       - pr-sandbox-argocd-webhook-auth
       - pr-sandbox-argocd-readonly-user-password
       - pr-sandbox-extra-configs
diff --git a/pyproject.toml b/pyproject.toml
index fc8bbc2..961e65f 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,6 +11,7 @@ dependencies = [
     "pydantic-settings>=2.11.0",
     "pyjwt>=2.10.1",
     "pymysql>=1.1.2",
+    "redis>=7.1.0",
     "requests>=2.32.5",
     "sqlmodel>=0.0.27",
 ]
diff --git a/uv.lock b/uv.lock
index e62bbf5..afd0201 100644
--- a/uv.lock
+++ b/uv.lock
@@ -508,6 +508,7 @@ dependencies = [
     { name = "pydantic-settings" },
     { name = "pyjwt" },
     { name = "pymysql" },
+    { name = "redis" },
     { name = "requests" },
     { name = "sqlmodel" },
 ]
@@ -525,6 +526,7 @@ requires-dist = [
     { name = "pydantic-settings", specifier = ">=2.11.0" },
     { name = "pyjwt", specifier = ">=2.10.1" },
     { name = "pymysql", specifier = ">=1.1.2" },
+    { name = "redis", specifier = ">=7.1.0" },
     { name = "requests", specifier = ">=2.32.5" },
     { name = "sqlmodel", specifier = ">=0.0.27" },
 ]
@@ -705,6 +707,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/f1/12/de94a39c2ef588c7e6455cfbe7343d3b2dc9d6b6b2f40c4c6565744c873d/pyyaml-6.0.3-cp314-cp314t-win_arm64.whl", hash = "sha256:ebc55a14a21cb14062aa4162f906cd962b28e2e9ea38f9b4391244cd8de4ae0b", size = 149341, upload-time = "2025-09-25T21:32:56.828Z" },
 ]
 
+[[package]]
+name = "redis"
+version = "7.1.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/43/c8/983d5c6579a411d8a99bc5823cc5712768859b5ce2c8afe1a65b37832c81/redis-7.1.0.tar.gz", hash = "sha256:b1cc3cfa5a2cb9c2ab3ba700864fb0ad75617b41f01352ce5779dabf6d5f9c3c", size = 4796669, upload-time = "2025-11-19T15:54:39.961Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/89/f0/8956f8a86b20d7bb9d6ac0187cf4cd54d8065bc9a1a09eb8011d4d326596/redis-7.1.0-py3-none-any.whl", hash = "sha256:23c52b208f92b56103e17c5d06bdc1a6c2c0b3106583985a76a18f83b265de2b", size = 354159, upload-time = "2025-11-19T15:54:38.064Z" },
+]
+
 [[package]]
 name = "requests"
 version = "2.32.5"