Local processing
Traffic is handled on your machine. The inspection workflow does not depend on shipping traffic to a third party.
Built for macOS developers
Source availableFlowProxy
Modern HTTPS debugging proxy for macOS
Inspect, modify, and replay HTTP and HTTPS traffic with a clean native interface built for focused debugging. Built for AI agents from the start — connect Claude Code or Codex over MCP and let them read your traffic directly.
AIAI agent guide — connect Claude Code or Codex over MCPVersion 1.1·macOS 13 or later·Source available
No network traffic or debugging data is sent to external services
Powerful features
Everything you need to inspect network traffic with clarity and speed.
Inspect HTTP and HTTPS traffic in real time
View request and response headers, bodies, and timing
JSON, URL-encoded, and form-data body viewers
Filter sessions by host, method, or status code
Replay any request — override method, headers, or body
CLI for scripting, automation, and AI agent workflows
Native Swift — no Electron, no cloud dependency
Source available — readable on GitHub
FlowProxy
Port 8888
AllXHRHTMLJSCSSImage
GET
www.microsoft.com
386 B
GET
www.microsoft.com
0.3 kB
POST
browser.events.data.microsoft.com
3.8 kB
GET
www.microsoft.com
2 kB
GET
nimbus.bitdefender.net
69 kB
POST200browser.events.data...
RequestResponseHeadersTiming
RESPONSE BODY
<html lang="en">
<head>
<meta charset="utf-8"/>
</head>
<body>...
● Listening on port 8888111 of 111 sessions
Clean, native interface
Designed to feel at home on macOS while keeping dense debugging data readable at a glance.
FlowProxy
■ StopPort 8888
AllXHRHTMLJSCSSImageFontMediaOther
⌕Filter sessions...
GET200
detectportal.firefox.com
/canonical.html
90 B
17:28:13
GET200
www.microsoft.com
/AlexaTopSites/carousel
386 B
17:28:14
GET200
www.microsoft.com
/AlexaTopSites/officetools
388 B
17:28:14
POST200
www.microsoft.com
/account/signin-oidc
506 B
17:28:38
GET200
login.live.com
/oauth20_authorize.srf
215 B
17:28:39
GET200
malware-filter.pages.dev
/urlhaus-filter-ag-online
322 KB
17:28:40
POST200https://www.microsoft.com/account/signin-oidc
RequestResponseHeadersCookiesTiming
text/htmlRaw
RESPONSE BODY
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
</head>
<body>
<script nonce="eXB1Hj3...">
if (cascadeAuth.API && typeof cascadeAuth.API
.silentAuthCallback === "function") {
cascadeAuth.API.silentAuthCallback(userInfo);
}
</script>
● Listening on port 8888111 of 111 sessions · 5 errors
Why FlowProxy?
Built for macOS developers who need a fast, reliable, and visually calm debugging proxy without extra noise.
Native macOS — no Electron
Pure Swift. Launches fast, runs light, and integrates with macOS conventions instead of fighting them.
Capture and replay
Any session can be replayed instantly. Override the method, headers, or body to test a fix without switching tools.
CLI built in
Every feature is accessible from the terminal. Script workflows, pipe results to jq, or drive it from an AI agent.
Local only, always
Zero external calls. Your traffic, headers, and credentials never leave the machine.
<10ms
Request capture latency
100%
Native Swift code
9.8MB
Lightweight app size
0
Cloud dependencies
Command-line interface
Built for the terminal too
Every feature in the GUI is available via the flowproxy CLI. Script traffic capture, automate replays, and pipe sessions straight into jq — all with stable JSON output.
Not in the Mac App Store build. Sandboxing rules out a command-line tool, so the CLI ships only in the direct download. Agents are unaffected — they reach the same traffic over MCP, which every build has.
flowproxy — zsh
Start the proxy
$flowproxy proxy start --json
{ "port": 8888, "running": true }
Filter sessions by host and method
$flowproxy sessions list --host api.example.com --method POST --json
{ "count": 3, "sessions": [ { "id": "B5E9...", "status": 201, ... } ] }
Replay with a new auth token
$flowproxy replay B5E91BA5-... --header "Authorization: Bearer newtoken" --json
{ "status": 200, "duration_ms": 143, "responseBody": "..." }
AI agent access
Your agent drives the proxy. Over MCP, not screenshots.
Point Claude Code, Codex, Claude Desktop, Cursor, or VS Code at FlowProxy and your agent can start the proxy, list and read captured sessions, and replay a request with changed headers — reading structured JSON, not a screenshot of a window.
The tools your agent gets
list_sessionsEvery captured request, filterableget_sessionFull headers, body, and timing for oneproxy_statusIs it running, and on which portclear_sessionsEmpty the capture bufferstart_proxyBring the proxy upstop_proxyTake it downreplay_sessionRe-send with overridden method, headers, or body
One line to connect
The app has a picker for Claude Code, Codex, Claude Desktop, Cursor, and VS Code — choose your client and copy the snippet it generates.
No CLI, no daemon
Works inside the sandboxed App Store build. Nothing to install alongside it and no background process to keep running.
Off by default, revocable
Agent access starts switched off. Every call carries a bearer token, and one switch cuts access immediately.
Privacy first
Network traffic is sensitive. FlowProxy treats that as a default assumption, not a marketing line.
No external servers
The product is designed around direct local analysis instead of remote processing infrastructure.
Transparent debugging
Headers, payloads, cookies, and timing remain visible and under operator control throughout the workflow.
A calmer way to debug HTTP traffic
A native HTTPS debugging proxy for macOS, with MCP access so your AI agent can read captured traffic directly. Inspect, modify, and replay without anything leaving your machine.
Get on the Mac App Store·USD 1.99Version 1.1 · macOS 13.0 or later