Introducing IO Ninja

IO Ninja is a professional all-in-one terminal emulator, sniffer, and protocol analyzer. IO Ninja is highly modular and has plugins for most transports and protocols you might сome across — network (TCP, UDP, SSL, SSH, WebSockets, etc.), serial (RS-232, RS-485, I2C, SPI, Modbus RTU, etc.), and others (named & anonymous pipes, USB endpoints, J-Link RTT, etc.). IO Ninja is scriptable and allows you to generate packets programmatically, react to incoming packets and other IO events, and create non-standard protocol analyzers.

IO Ninja is your swiss-army knife for debugging communications and a must-have tool for network security experts, system administrators, and all developers who deal with network programming in their line of work.

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IO Ninja Is Used At

Hardware Sniffers

We are proud to introduce three hardware sniffers for IO Ninja. These devices are simple yet functional and convenient sniffers for asynchronous serial links (RS232, RS422, RS485, TTL-level UART), synchronous serial links (I2C, SPI) communications, and Ethernet.


IO Ninja 5.1.2 is out!

  • Dispatch Interface for session-specific actions and other In-App Scripting improvements
  • Copy timestamps & offsets from the log
  • Reset layout of the main window
  • X-Term compatibility improvements

In-App Scripting improvements

In-App Scripting is a great tool for automating your testing routine. It works in any session, and as such, it was originally designed to only expose the generic functionality: write to log, establish a connection, send a block of data, etc. However, often times it is necessary to perform session-specific actions, such as setting baud rate to 115220 bps on a serial port. Starting with this release, it becomes possible via a session dispatch object called g_session. For example, inside a Serial session, you can:

// configure the port..."COM1");
g_session.m_baudRate = 115200;
g_session.m_dataBits = 8;
g_session.m_stopBits = io.SerialStopBits._1;
g_session.m_parity = io.SerialParity.None;
g_session.m_dtr = true;

// work with the device...

We also introduced high-level functions transmitAll() and receiveAll(). These will block the in-app scripting thread until the buffer is transferred completely or an error occurs. The blocking receive() function now also accepts the third timeout parameter. This allows for a convenient handling of situations when a device doesn't respond:


char buffer[256];
size_t size = receive(buffer, sizeof(buffer), 1000); // give the device one second to respond
if (!size) {
    // no response from the device

Copy timestamps & offsets from the log

Over the years, we received numerous questions from our users about how to copy timestamps from the log. Alas, the only possible way was by saving the log as a text file first. Well, now you can do it directly! Ctrl + mouse click on a timestamp induces full-line selection, including timestamps. It's also possible to select and copy data with binary offsets but without timestamps. Yes, you guessed it right, it's done via a Ctrl + mouse click on the offset column . And yes, this works in the hex-editor, too!

For a complete list of changes, see changelog.txt (also included in all installation packages).

Previous release announcements

Why You Should Use IO Ninja

Text vs Binary

Some protocols are text-based, and some are binary. Choose the representation that works best in each particular case and switch between the two kinds of data views any time you want.

Clear Timeline

Communications do not only consist of incoming and outgoing data — there are all kinds of other events (connect, disconnect, error, etc.) IO Ninja records everything in a single continuous log sheet to give you a clear timeline of events.

Regex Colorizer

Having too much information before your eyes can be counterproductive. Focus on what's important by automatically highlighting data in the log based on regular expression patterns.

Checksum Calculator

Many protocols use checksums to verify the integrity of data. IO Ninja calculates all standard checksums on the fly as you select data in the log then conveniently displays the results in a table together with local throughputs, time differences, byte offsets, etc.

Multiple Copy Modes

Сopy data from the log any way you want — as text, hex, C-array, etc. IO Ninja is smart and can guess what you want from the selection pattern so that a simple Ctrl+C always yields intuitive results.

Terminal Emulator

Sometimes, all you want is the classic terminal rendition of the incoming data. IO Ninja features a fully compatible X-Term terminal view to let you work with remote Linux boxes normally.

Transmission Facilities

IO Ninja features convenient and powerful tools for preparing packets before transmission. There's a plain text editor, a modern hex editor, and a file transmit facility — choose what works best.

Packet Templates

Even when you have a good hex editor, encoding fields of a binary packet by hand is hard and error-prone. With the Packet Template engine, you describe the packet structure in a C-like language, then conveniently edit your packet in the property grid.

Packet Library

Every time you transmit a packet, it goes to the Packet History pane. Re-transmit any packet with a double click, assign mnemonic names to packets, and build libraries of packets used in your line of work.

Redirect Anything

The Session Linking engine lets you redirect anything to anythingSerialTCP, UDPSSL, SSHWebSocket, etc. Start and configure two sessions, then click Link Sessions and voila! All the data will be propagated from one session to the other.


Sometimes you need to automate your testing routine. With the Script Pane, you can generate packets programmatically, wait for and react to events, automatically respond to incoming packets, etc.

Extensible Arch

IO Ninja is highly modular and all the plugins are open-source. See how they are implemented, modify any to your liking, or build something completely new. To make things convenient, do it with the code-assisting IDE that we use ourselves!

Interfaces, Transports, Protocols


Serial remains one of the most widely interfaces in IoT and industrial automation. IO Ninja provides you with a rich toolset for debugging serial communications.

Serial Tap
Serial Terminal
Serial Monitor


Hardware and software Ethernet sniffers in IO Ninja shine at live reconstruction of TCP & UDP data streams. We also provide full interoperability with the industry leader in packet capturing that is Wireshark.

Ethernet Tap
Ethernet Tap over SSH
Pcap Sniffer


Our hardware sniffer for I2C/SPI will give you the most convenient and easy-to-follow data view of I2C and SPI data streams. Works better than logic analyzers when you are interested in high-level data rather than the low-level signal details.



TCP is rightfully called the language of the Internet. IO Ninja turns you into a professional linguist in this department.

TCP Terminal
TCP Server Terminal
TCP Flow Monitor


Not as widespread as TCP, the UDP protocol has its undisputed domain of application. With IO you have all the necessary tools to troubleshoot the connectionless UDP comms.

UDP Terminal
UDP Flow Monitor
UDP Flow Analyzer


SSL is the transport of the modern Web. IO Ninja gives you powerful terminals to work on both client and server sides of SSL connections.

SSL Terminal
SSL Server Terminal


Whenever you talk to a remote Linux box, you need SSH — so of course, there's a convenient SSH terminal in IO Ninja.

SSH Terminal


WebSockets are widely used in Web applications nowadays. IO Ninja features both client and server side terminals to help debugging your next WebSocket application.

WebSocket Terminal
WebSocket Server Terminal


Named and anonymous pipes are important methods of inter-process communications (IPC). IO Ninja provides unique tools for pipe traffic generation and analysis. A must have for CompuSec researches!

File Stream Terminal
Named Pipe Server Terminal
Pipe Monitor


We proudly present you the unique low-level USB endpoint terminals. These are indispensible tools if you develop a USB device that doesn't fall into a predefined standard device category.

USB Data Endpoint Terminal
USB Control Endpoint Terminal


IO Ninja is the best Modbus analyzer on the market, and we plan to gradually expand the list of supported automation protocols. Our protocol analyzers are implemented as layers so that they can be applied to raw data captured with any plugin.

Modbus Analyzer
DF1 Analyzer


IO Ninja is truly versatile, so there's much more than could be fit into the categories above.

J-Link RTT Terminal
Replay Log
TX Modifier