diff --git a/include/libcamera/camera.h b/include/libcamera/camera.h
index 6d693d9a6c7a..21fac550f412 100644
--- a/include/libcamera/camera.h
+++ b/include/libcamera/camera.h
@@ -10,6 +10,7 @@
 #include <map>
 #include <memory>
 #include <set>
+#include <stdint.h>
 #include <string>
 
 #include <libcamera/controls.h>
@@ -93,7 +94,7 @@ public:
 	int allocateBuffers();
 	int freeBuffers();
 
-	Request *createRequest();
+	Request *createRequest(uint64_t cookie = 0);
 	int queueRequest(Request *request);
 
 	int start();
diff --git a/include/libcamera/request.h b/include/libcamera/request.h
index a93468d7c8b7..dd165bc21c03 100644
--- a/include/libcamera/request.h
+++ b/include/libcamera/request.h
@@ -8,6 +8,7 @@
 #define __LIBCAMERA_REQUEST_H__
 
 #include <map>
+#include <stdint.h>
 #include <unordered_set>
 
 #include <libcamera/controls.h>
@@ -29,7 +30,7 @@ public:
 		RequestCancelled,
 	};
 
-	explicit Request(Camera *camera);
+	Request(Camera *camera, uint64_t cookie = 0);
 	Request(const Request &) = delete;
 	Request &operator=(const Request &) = delete;
 
@@ -38,6 +39,7 @@ public:
 	int setBuffers(const std::map<Stream *, Buffer *> &streamMap);
 	Buffer *findBuffer(Stream *stream) const;
 
+	uint64_t cookie() const { return cookie_; }
 	Status status() const { return status_; }
 
 	bool hasPendingBuffers() const { return !pending_.empty(); }
@@ -56,6 +58,7 @@ private:
 	std::map<Stream *, Buffer *> bufferMap_;
 	std::unordered_set<Buffer *> pending_;
 
+	uint64_t cookie_;
 	Status status_;
 };
 
diff --git a/src/libcamera/camera.cpp b/src/libcamera/camera.cpp
index 810cb1295f34..1f307654ab01 100644
--- a/src/libcamera/camera.cpp
+++ b/src/libcamera/camera.cpp
@@ -754,10 +754,16 @@ int Camera::freeBuffers()
 
 /**
  * \brief Create a request object for the camera
+ * \param[in] cookie Opaque cookie for application use
  *
  * This method creates an empty request for the application to fill with
  * buffers and paramaters, and queue for capture.
  *
+ * The \a cookie is stored in the request and is accessible through the
+ * Request::cookie() method at any time. It is typically used by applications
+ * to map the request to an external resource in the request completion
+ * handler, and is completely opaque to libcamera.
+ *
  * The ownership of the returned request is passed to the caller, which is
  * responsible for either queueing the request or deleting it.
  *
@@ -766,12 +772,12 @@ int Camera::freeBuffers()
  *
  * \return A pointer to the newly created request, or nullptr on error
  */
-Request *Camera::createRequest()
+Request *Camera::createRequest(uint64_t cookie)
 {
 	if (disconnected_ || !stateBetween(CameraPrepared, CameraRunning))
 		return nullptr;
 
-	return new Request(this);
+	return new Request(this, cookie);
 }
 
 /**
diff --git a/src/libcamera/request.cpp b/src/libcamera/request.cpp
index f0b5985814bd..8cf41a43a80e 100644
--- a/src/libcamera/request.cpp
+++ b/src/libcamera/request.cpp
@@ -46,9 +46,17 @@ LOG_DEFINE_CATEGORY(Request)
 /**
  * \brief Create a capture request for a camera
  * \param[in] camera The camera that creates the request
+ * \param[in] cookie Opaque cookie for application use
+ *
+ * The \a cookie is stored in the request and is accessible through the
+ * cookie() method at any time. It is typically used by applications to map the
+ * request to an external resource in the request completion handler, and is
+ * completely opaque to libcamera.
+ *
  */
-Request::Request(Camera *camera)
-	: camera_(camera), controls_(camera), status_(RequestPending)
+Request::Request(Camera *camera, uint64_t cookie)
+	: camera_(camera), controls_(camera), cookie_(cookie),
+	  status_(RequestPending)
 {
 }
 
@@ -119,6 +127,12 @@ Buffer *Request::findBuffer(Stream *stream) const
 	return it->second;
 }
 
+/**
+ * \fn Request::cookie()
+ * \brief Retrieve the cookie set when the request was created
+ * \return The request cookie
+ */
+
 /**
  * \fn Request::status()
  * \brief Retrieve the request completion status