TPeek

Debug what your app actually receives over TCP. A lightweight Go binary. No dependencies.

TPeek is a transparent TCP proxy that shows you, in real time, the exact bytes flowing between two applications. It sits silently between a client and a server, forwarding traffic untouched while printing every read to your terminal — block by block, with timestamps and direction.

[14:32:01.482] 🔵 Client → 47 bytes
  GET /api/users HTTP/1.1
  Host: localhost
  Accept: application/json

[14:32:01.489] 🟢 Server → 128 bytes
  HTTP/1.1 200 OK
  Content-Type: application/json
  Content-Length: 42

  {"users":[{"id":1,"name":"michel"}]}

---

Why TPeek

1. You see what your app receives, not what the network carries

Sniffers like Wireshark or tcpdump show packets — fragmented, reassembled by the OS later. TPeek shows you exactly what arrives in your application's buffer, one Read() call at a time. This is what your code actually sees.

2. Built for binary protocols, not just HTTP

Toggle between plain text and full hexadecimal dump. Inspect MySQL handshakes, Redis commands, custom binary protocols, or proprietary wire formats without writing a custom parser.

tpeek -l 0.0.0.0:8000 -t 127.0.0.1:3306 -hex

3. Fragmentation-aware

Each block of data is printed exactly as received from the syscall — never merged, never reformatted. You see how the protocol fragments its messages, which is critical when debugging streaming protocols, slow clients, or chunked responses.

4. Millisecond timestamps

Every read is timestamped. You can immediately measure round-trip latency, identify slow responses, or detect timing bugs between client and server.

5. Safe for production debugging

Binary data is forwarded untouched. Only the terminal output is sanitized so unprintable bytes don't crash your shell. You can use TPeek in front of a real service without risk of corrupting the wire format.

6. Single binary. Zero runtime. Zero dependencies.

No Python, no Node, no Docker image, no library to install. One Go binary you drop on a server, a laptop, or inside a container.

---

When to use TPeek

• You're integrating a third-party API and the docs don't match what's actually sent
• You need to reverse-engineer or debug a proprietary binary protocol
• You're comparing the wire behavior of two different database clients
• You want to see if a slow request is the client, the network, or the server
• You're debugging a microservice mesh and need a quick view of what one service sends to another

---

Installation

Linux (precompiled)

sudo wget https://github.com/michelphp/tpeek/releases/download/1.0.0/tpeek-linux -O /usr/local/bin/tpeek
sudo chmod +x /usr/local/bin/tpeek

From source

git clone https://github.com/michelphp/tpeek
cd tpeek
go build -o tpeek

---

Usage

Inspect TCP traffic between an app and MySQL

tpeek -l 0.0.0.0:8000 -t 127.0.0.1:3306

Then point your application at localhost:8000 instead of localhost:3306. Every query, every response, every byte — visible.

Inspect a binary protocol (Redis, custom RPC, proprietary protocols)

tpeek -l 0.0.0.0:8000 -t 127.0.0.1:6379 -hex

Inspect an HTTP API

tpeek -l 0.0.0.0:8080 -t api.example.com:80

---

Command line flags

Flag	Description	Default
-l	Local address and port to listen on
-t	Target service address and port
-hex	Enable full hexadecimal dump mode	false

---

Comparison

	Wireshark / tcpdump	TPeek
View	Network packets	App-level reads
Binary protocol friendly	Requires dissectors	Hex mode native
Proxy mode (man-in-the-middle)	Manual setup	One command
Runtime dependencies	libpcap + tools	None
Installation	Package + privileges	Drop one binary
Terminal-safe output	N/A	Sanitized

TPeek is not a replacement for Wireshark. It's a different lens — closer to what your application sees, simpler to deploy.

---

License

GNU Affero General Public License v3.0 (AGPL-3.0)