See every HTTP request. Rewrite responses. Simulate slow networks. Automate your entire proxy config with 40+ REST endpoints — the workflow Charles Proxy and Fiddler should have shipped years ago. Single binary. Runs everywhere. Starts free.
Keep upstream validation on by default, install the local CA only where you intend to inspect, and follow platform-specific mobile guidance.
The tour points at the live controls so new users can capture traffic, trust certificates, and open settings without hunting.
One binary. Double-click to launch. No installer, no Java runtime, no Docker required. The proxy starts automatically on port 8888.
Set localhost:8888 as your HTTP proxy. Works with browsers, mobile apps, React, Node, Python — anything that speaks HTTP.
Every request appears instantly in the desktop app. Then automate — create rewrite rules, throttle profiles, and filters via the REST API. No clicking required.
Full MITM proxy with auto-generated certificates. Inspect encrypted traffic between any client and any server, including mobile apps.
Map Remote, Map Local, header inject/modify/remove, body find & replace, URL rewriting, status code overrides. All via API or GUI.
16 built-in presets from 56K modem to 5G fiber. Custom latency, bandwidth caps, and packet loss simulation. Test edge cases instantly.
Search across URLs, headers, request/response bodies. Filter by method, status code range, or hostname. Find the needle in your haystack.
Re-send any captured request with one click, or compose custom requests from scratch. Like Postman built into your proxy.
Save, load, import, and export capture sessions. Share compressed .pcsession files with teammates or attach them to bug reports.
Export to standard HTTP Archive format. Import into Chrome DevTools, Lighthouse, or any HAR-compatible tool for further analysis.
Get notified via Slack in real-time when specific patterns appear. Monitor for 5xx errors, slow responses, or custom conditions. Email notifications coming soon.
Core proxy workflows exposed via a clean REST API with OpenAPI docs. Script your proxy config in CI/CD, tests, or any language you use.
| Feature | ProxyCat | Charles Proxy | Fiddler | mitmproxy | Proxyman |
|---|---|---|---|---|---|
| SSL/HTTPS Interception | ✓ | ✓ | ✓ | ✓ | ✓ |
| REST API for All Features | ✓ | ✗ | ✗ | Scripting | ✗ |
| Map Remote / Map Local | ✓ | ✓ | ✓ | Manual | ✓ |
| Header & Body Rewriting | ✓ | ✓ | ✓ | ✓ | ✓ |
| Network Throttling (16 presets) | ✓ | 3 presets | Basic | ✗ | Basic |
| Packet Loss Simulation | ✓ | ✗ | ✗ | ✗ | ✗ |
| Full-Text Search | ✓ | Basic | ✓ | CLI filter | ✓ |
| Request Replay & Compose | ✓ | Repeat only | ✓ | CLI replay | ✓ |
| Session Save / Export / Import | ✓ | ✓ | ✓ | HAR only | ✓ |
| HAR Export | ✓ | ✓ | ✓ | ✓ | ✓ |
| Interactive API Docs (Scalar) | ✓ | ✗ | ✗ | ✗ | ✗ |
| Slack Notifications | ✓ | ✗ | ✗ | ✗ | ✗ |
| Docker / Headless Mode | ✓ | ✗ | ✗ | ✓ | ✗ |
| Cross-Platform Desktop App | ✓ | ✓ | Win only | CLI only | Mac only |
| CI/CD Integration | ✓ | ✗ | ✗ | Scripting | ✗ |
| 1,000 req/day free | ✓ | ✗ | Limited | ✓ | Limited |
| Embedded Server (single binary) | ✓ | ✗ | ✗ | ✗ | ✗ |
| Web-Based UI | ✓ | ✗ | Limited | ✓ | ✗ |
| Automate via REST API (CI/CD) | ✓ | ✗ | ✗ | Python only | ✗ |
| ARM64 / Apple Silicon native | ✓ | ✓ | ✗ | ✓ | ✓ |
| Persists rules across restarts | ✓ | ✓ | ✓ | ✗ | ✓ |
| Pricing | Free / $9/mo | $50/yr | Free / $12/mo | Free | $69/yr |
localhost:8888, install the root cert once, and your team is capturing HTTPS traffic. Import your Charles .p12 cert if you want to keep the same certificate chain.curl awayAll downloads also include a standalone headless server binary in the server/ subfolder.
Actually free. No time limit, no credit card, no account required. Download the binary and use it forever. The free tier includes all core features — SSL interception, all rewrite types, all 16 throttle presets, full-text search, replay, compose, and full REST API access. The only limits are 1,000 requests/day and 10 filter rules.
Charles is a great GUI tool, but it has no API, no automation support, no CI/CD integration, and costs $50/year. ProxyCat gives you the same interception and rewrite capabilities plus 40+ REST API endpoints, so you can script your entire proxy setup. It ships as a single self-contained binary — no Java runtime, no installer wizard, no license dialogs on every launch.
Under 10 minutes. Download the binary, run it, set your browser or device proxy to localhost:8888, and install the root certificate once. If you're using Charles certificates in your app, you can import your existing .p12 file via the Cert Viewer. Your filters and rewrite rules are JSON — version-control them from day one.
mitmproxy's Python addon system is powerful but forces you to write and maintain proxy code in a specific runtime. ProxyCat exposes everything via a clean REST API — use any language, any tool, any CI platform. Run rewrite rules in your test suite with two curl commands. No Python environment to manage, no addon reload cycle. You get full headless server support via Docker too.
Absolutely. Every download includes a headless server binary you can run without a GUI. There's also a Docker image. Set up rewrite rules, filters, and throttle profiles with curl commands in your pipeline scripts. Teams use it to mock external APIs in integration tests and simulate network failures.
Yes. ProxyCat generates its own root CA certificate on first launch. Install it on your device or browser to intercept TLS/SSL traffic. Works with iOS, Android, desktop browsers, and any HTTP client. Certificate setup takes about 30 seconds.
At 1,000 requests/day, new requests stop being captured but the proxy keeps forwarding traffic normally — nothing breaks. Your existing captures, search, and REST API all keep working. No forced upgrades, no nag screens. Upgrade to Pro when (and if) you need unlimited.
Yes. Rewrite rules, filter sets, and session captures can all be exported via the API and shared as JSON or .pcsession files. Pro users can save and load sessions directly. Teams typically version-control their proxy configs alongside their test suites.
Download ProxyCat, start it, and see your first captured request in under 60 seconds. Free forever. No account. No credit card. No catch.