Open-source DDS introspection
Ask the live DDS system what is happening.
Discover participants, endpoints and topics. Inspect QoS, types and instances. Read live application data from a focused command-line workflow without changing your application code.
Structured entity and data output
Explore manually or query from scripts
Open-source and developed by eProsima
>> participants- name: perception_node
guid: 01.0f...c1
- name: navigation_node
guid: 01.0f...d7
>> topics Robot* vvname: RobotPose
type: PoseType
writers: 1 · readers: 2
rate: 30.02 Hz
dynamic_type_discovered: true
>> echo RobotPoseposition:
x: 14.82
y: 03.16
orientation:
yaw: 1.5708
OPEN SOURCE Focused DDS investigation, built in the open.
DDS Spy is developed by eProsima and available under the Apache 2.0 license.
Core capabilities
Move from DDS structure to live data.
Start with the entities that form the system, then narrow the investigation until the behavior you need is visible in the terminal.
- Map the active DDS system
- Inspect communication context
- Echo topic data in real time
- Understand the data model
- Filter and automate the query
Map the active DDS system
Query the participants, DataWriters and DataReaders currently active in the domain, then inspect the relationships behind each endpoint.
- Participant names and GUIDs
- Reader and writer endpoints
- Compact or verbose output
- No application instrumentation
Inspect communication context
See which topics are active, the types they use, their endpoint counts and publication rates, then reveal endpoint QoS when more detail is required.
- Topic names and data types
- Writer and reader counts
- Subscription rate in samples per second
- Reliability and durability visibility
Echo topic data in real time
Subscribe to discovered topics and print incoming samples in a human-readable structure directly in the terminal.
- Single-topic or wildcard echo
- Verbose source information
- Human-readable nested data
- Continuous output until stopped
Understand the data model
Use discovered DynamicTypes to inspect a topic's IDL definition, identify key fields and understand the instances present in the system.
- IDL type definitions
- Key-field discovery
- Instance counts and key values
- Automatic DynamicType discovery
Filter and automate the query
Limit the observed data set with topic and partition filters, or run a command once and return structured output to scripts and automation.
- Topic and partition filters
- Wildcard topic matching
- Interactive and one-shot modes
- YAML and XML-based configuration
A focused investigation path
Discover. Query. Read the evidence.
Use the same compact sequence for an integration check, a field investigation or an automated deployment test.
Connect
Start DDS Spy in the target domain using the default setup or a YAML configuration.
Discover
List active participants, endpoints and topics to establish the live communication context.
Inspect
Query QoS, rates, type definitions, keys and instance details where the investigation needs depth.
Echo
Read selected topic samples in real time or use one-shot output in an automated check.
A command for each question
Stay close to the DDS system.
The interactive CLI keeps exploration immediate. The same commands can run in one-shot mode when scripts or test environments need structured output.
Establish the topology
participants · writers · readersInspect communication
topics · topics <name> idl · keysRead the data
echo <topic> · echo all$ fastddsspy --domain 0
>> topics
- topic: RobotPose (PoseType) (1|2) [30.02 Hz]
- topic: MissionState (StateType) (1|1) [5.00 Hz]
>> topics RobotPose idl
struct PoseType {
double x;
double y;
double yaw;
};
>> echo RobotPose
position: { x: 14.82, y: 3.16 }
yaw: 1.5708Operational confidence
A lightweight tool for focused engineering questions.
Use DDS Spy when the fastest route to an answer is a terminal connected to the live domain.
Verify integration
Confirm that expected participants, topics, types and endpoints appear when two systems are brought together.
Diagnose from a terminal
Investigate remote or headless environments where a lightweight CLI is faster than a graphical workspace.
Build repeatable checks
Use one-shot commands and structured output as focused evidence in test, deployment and support workflows.
Choose the investigation experience
DDS Spy or DDS Monitor Pro?
DDS Spy is the focused open-source CLI for direct inspection and automation. DDS Monitor Pro is the visual engineering workspace for topology, charts, recordings and multi-view diagnosis.
- Terminal access in remote or headless environments
- Fast, focused inspection
- Commands for scripts and automated checks
- Visual and multi-view diagnosis
- Charts, topology and video visualization
- Live and recorded-system analysis
Capability | Open source DDS Spy | Commercial DDS Monitor Pro |
|---|---|---|
Primary interface | Command-line interface | Graphical workspace |
Command-line investigation | Included | Complementary |
Interactive and one-shot queries | Included | - |
Live topic-data inspection | Included | Included |
Visual topology and multiple views | - | Included |
Charts, video and offline analysis | - | Included |
License | Apache 2.0 | Commercial |
Professional support
Turn terminal evidence into a faster resolution.
DDS Spy is open source. When the investigation reveals an architectural, QoS or integration problem, eProsima can help your team resolve it through a Fast DDS Pro or Safe DDS support path.
DDS entity and discovery analysis.
Topic, type and QoS troubleshooting.
Configuration and automation guidance.
Architecture and integration support.
