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STREAM / BINARY FRAMES

TCP device debugging starts with the right frame boundaries.

Inspect stream data, validate your framing configuration and compare acknowledgements with the protocol your device actually sends.

Start TCP testing →Read the setup guide

SingleIoT product guide · Updated October 14, 2026

UNDERSTAND THE EXCHANGE

What can you test with TCP?

TCP delivers a stream of bytes. A device application still needs a framing rule to decide where a message starts and ends. When that rule does not match the firmware, a valid payload can appear incomplete or several messages can arrive as one frame. SingleIoT exposes configurable framing alongside captured bytes to help you investigate these problems.

01

Device identity

Check token-based authentication or the supported identifier mode assigned to your device.

02

Frame boundaries

Compare delimiter, length-prefix, fixed-size or idle-gap configuration with the actual byte stream.

03

Acknowledgements

Verify both the outgoing reply bytes and the device’s interpretation of the response.

SET UP YOUR FIRST TEST

How to test a TCP device in SingleIoT

  1. 1

    Choose TCP and the connection mode

    Create a TCP device and review its endpoint and authentication settings. Fixed-protocol hardware may require an enabled protocol definition and identifier configuration.

  2. 2

    Match the framing rule

    Set delimiter, length-prefix, fixed-size or idle-gap framing to match your firmware. Begin with one complete message before testing bursts.

  3. 3

    Connect and send a known frame

    In the default token-based mode, send the device token as the first line. Then send the payload using the device’s configured frame boundaries.

  4. 4

    Inspect bytes and reply behavior

    Use hexadecimal or text views to compare the frame with the source. Configure a reply rule and check the outgoing acknowledgement before repeating the test.

TCP connection example

Start with a known message, then compare it with the captured frame.

TCP · illustrative setup
Example: token authentication with newline framing

<device token>\n
{ "temperature": 26.5 }\n
{ "temperature": 27.0 }\n

The displayed \n means a newline byte, not two literal characters. This example applies to token-based devices configured with a newline delimiter. Identifier-mode devices use the selected protocol definition instead.

Common TCP testing problems

Change one setting at a time and use captured traffic to verify the result.

Connection opens, but no frame is captured

Verify the initial token line in token mode. Then check whether the configured framing rule is waiting for a delimiter, more bytes or an idle interval.

Two payloads appear as one frame

Check delimiters or configured length fields. With idle-gap framing, a continuous burst can be grouped until the configured idle interval is reached.

Binary data looks unreadable

Switch to the hexadecimal view. Compare byte positions and field lengths rather than treating a binary frame as UTF-8 text.

Device rejects the server reply

Check the reply format, payload match and protocol definition. Compare the acknowledgement bytes with the format expected by the device.

TCP testing questions

Which TCP framing modes are supported?

SingleIoT supports delimiter, length-prefix, fixed-size and idle-gap framing for configurable TCP devices. Select the mode that matches your device’s messages.

Can I test a TCP device over TLS?

Supported TCP endpoints can use TLS. Confirm your assigned endpoint, plan availability, certificate trust and any client certificate requirements in the device workspace.

See what your TCP device actually sends.

Create a device workspace and inspect your first frame.

Create your workspace →