diff --git a/docs/how-to/just-run-blueapi-and-services-locally.md b/docs/how-to/just-run-blueapi-and-services-locally.md
index 5a8303b42..3e434d35d 100644
--- a/docs/how-to/just-run-blueapi-and-services-locally.md
+++ b/docs/how-to/just-run-blueapi-and-services-locally.md
@@ -25,6 +25,11 @@ Before starting, ensure you have followed the [Installation instructions](../tut
     - `just repl`: will give you a repl with pre-configured and logged in client
     - `just compose down`: tear down adjacent services
 
+6. On the Diamond network you can also run the NeXus file converter, which writes NeXus files from the documents blueapi publishes to RabbitMQ:
+    - `just compose-diamond`: launch the services above plus the converter
+    - Written files appear in `/tmp/blueapi-nexus` on the host (override with `NEXUS_OUTPUT_DIR`)
+    - `just compose --profile diamond down`: tear down everything, including the converter
+
 Channel Access
 
 To log in through the BlueAPI CLI:
diff --git a/justfile b/justfile
index 23c5aacd6..fdf5ebd83 100644
--- a/justfile
+++ b/justfile
@@ -24,6 +24,9 @@ init-example-services:
 compose +ARGS="up -d --no-recreate": init-example-services _check-runner
     {{ RUNNER }} compose -f tests/system_tests/compose.yaml {{ ARGS }}
 
+[doc('Bring up the example services plus the NeXus file converter (Diamond registry only)')]
+compose-diamond: (compose "--profile diamond up -d --no-recreate")
+
 [doc('Run the blueapi server with the system test config')]
 serve *OPTS:
     #!/usr/bin/env bash
diff --git a/tests/system_tests/compose.yaml b/tests/system_tests/compose.yaml
index 25570146b..573bbde0d 100644
--- a/tests/system_tests/compose.yaml
+++ b/tests/system_tests/compose.yaml
@@ -154,3 +154,24 @@ services:
         condition: service_healthy
     security_opt:
       - label=disable
+
+  # Internal Diamond registry so not pulled in CI, enable with `--profile diamond`
+  nexus:
+    profiles: [diamond]
+    image: gitlab.diamond.ac.uk:5050/daq/d2acq/services/nexus-file-converter:4.1.6
+    network_mode: host # Port 8084
+    environment:
+      - BEAMLINE=adsim
+      # Consume the start/descriptor/event/stop documents blueapi publishes
+      # on /topic/public.worker.event (amq.topic exchange)
+      - SPRING_PROFILES_ACTIVE=rabbitmq
+      - SPRING_RABBITMQ_HOST=localhost
+    volumes:
+      # numtracker's data_session_directory is /tmp/, expose written files on the host
+      - ${NEXUS_OUTPUT_DIR:-/tmp/blueapi-nexus}:/tmp
+    depends_on:
+      - rabbitmq
+    # rabbitmq has no healthcheck, retry until the broker accepts connections
+    restart: on-failure
+    security_opt:
+      - label=disable