What Charles does

Charles is a commercial web debugging proxy application developed and sold by XK72 Ltd, a privately held New Zealand software company founded in 2002 by Karl von Randow. The product is a Java-based HTTP proxy, HTTP monitor, and reverse proxy that operates as a man-in-the-middle between a user's machine and the Internet, capturing and displaying all HTTP, SSL/HTTPS, and HTTP/2 traffic including requests, responses, headers, and cookies. Charles offers a comprehensive feature set including SSL decryption via dynamically generated certificates, bandwidth throttling and latency simulation, breakpoints for request/response interception and editing, AMF and Protocol Buffers parsing, AJAX/JSON tree views, and load testing via request repetition. A companion iOS application extends network capture to mobile devices, and the desktop product is distributed across Windows, macOS, and Linux via direct download, APT, and YUM repositories.

The company operates a self-serve, product-led growth model: developers download a free trial directly from charlesproxy.com and purchase one-time licenses after evaluation, with paid upgrades between major versions (v3 to v4, v4 to v5). Marketing is minimal and content-driven, relying on the founder's blog, documentation, and Twitter presence rather than paid acquisition. The business is bootstrapped with no external venture capital, no institutional investors, and no disclosed headcount — the product appears to be maintained primarily by the founder, constituting a key-person dependency risk. The customer base is horizontal, targeting individual and small-team software and web developers globally, with no named enterprise customers, partnerships, or enterprise sales motion evident in the data.

Charles has shown continuous product development over two decades, with a notable acceleration in 2025–2026 including the major v5.0 release (modernised UI, dark mode, Apple Silicon and Windows ARM support), v5.1 (Java 25 virtual threads, zstd encoding), and v5.2 (HTTP/2 robustness, 103 Early Hints). The company has not pursued acquisitions, partnerships, or external funding, and its growth model is constrained by the one-time-license revenue structure and solo-operator scale.

Name

Charles

Legal name

XK72 Ltd

Website

https://charlesproxy.com

Company type

Private

Founded year

2002

Operating status

Operating

Short description

Charles (XK72 Ltd) is a bootstrapped New Zealand software company that develops and sells Charles Web Debugging Proxy, a Java-based HTTP/HTTPS debugging tool used globally by individual web and mobile developers for traffic inspection, SSL decryption, and bandwidth simulation via one-time self-serve licenses.

Ownership category

akta.pro rank

Headquarters

HQ city

Auckland

HQ country

New Zealand

HQ region

Oceania

Markets served

GTM type

B2C

Offering type

Software

Cost components

Personnel, Technology or R&D, Infrastructure, Marketing or Sales, Operations

Revenue model

1. Software License Sales: Charles generates revenue through direct software license sales. Users purchase a license to use the full version after their free trial expires. Major version upgrades (e.g., v3 to v4, v4 to v5) are paid upgrades.
2. Legacy Version Licensing: Charles 4 is offered as a paid upgrade from Charles 3, with previous versions (v3) still available for download to maintain backward compatibility.

Pricing tiers

Go-to-market motion1 record

Distribution channels5 records

Marketing channels4 records

Core offering

Charles is an HTTP proxy, HTTP monitor, and reverse proxy application built on Java that enables developers to view all HTTP, HTTPS, and SSL/TLS traffic between their machine and the Internet, including requests, responses, headers, and cookies. It is offered as a cross-platform desktop application for Windows, macOS, and Linux, plus a native iOS application, and includes features for SSL proxying, bandwidth throttling, breakpoints, repeat/load testing, and protocol-specific decoding for JSON, XML, AMF, and Protocol Buffers.

Product overview

Charles is a single, unified web debugging proxy application. The core product is Charles Web Debugging Proxy, available for Windows, macOS, and Linux as a desktop application. Charles for iOS extends the product to mobile devices, enabling network traffic capture directly on iOS. Legacy versions (Charles 4 and Charles 3) are still available for download as previous releases. The product provides HTTP monitoring, SSL proxying, bandwidth throttling, AJAX debugging, AMF/Flash remoting support, and various debugging tools including breakpoints, repeat, map remote/local, rewrite, and DNS spoofing.

Differentiator

Problem solved

Functional benefit

Products and services

• Charles Web Debugging Proxy (desktop) HTTP proxy, HTTP monitor, and reverse proxy desktop application for Windows, macOS, and Linux that lets developers view all HTTP, HTTPS, and SSL/TLS traffic between their machine and the Internet, including requests, responses, headers, and cookies. Sold to professional software and web developers as a one-time license after a free trial.
• Charles for iOS Native iOS application that captures and inspects HTTP and HTTPS network requests on iOS devices, allowing developers to view metadata, headers, and bodies directly on-device, including over cellular data. Distributed via the Apple App Store and through Apple's Volume Purchase Program for enterprise iOS teams.

Quantifiable outcome

• Makes debugging quick, reliable and advanced; saving time and frustration

Segments2 records

Ideal customer profiles2 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature9 records

Scale indicators1 record

Recent moves5 records

Expansion highlights3 records

Emerging players

• Insomnia (Kong): Cross-platform API client with HTTP request inspection and debugging features, now backed by Kong. Competes for developer mindshare on HTTP/API debugging workflows that overlap with Charles' core use case.
• Postman: API client and collaboration platform that has expanded into HTTP request inspection, mocking, and debugging. Adjacent rather than direct competition, but increasingly overlaps with Charles' workflows around HTTP/HTTPS request inspection and testing.
• HTTP Toolkit: Modern cross-platform HTTP debugging tool with one-click interception across desktop, mobile, and scripts; emerging direct competitor targeting developer workflows similar to Charles but with a contemporary UI and active release cadence.

Direct peers

• mitmproxy: Open-source, Python-based interactive HTTPS proxy widely used as a free alternative to Charles. Directly competes on the same HTTP interception and debugging functionality, with a command-line and web interface orientation.
• Fiddler (Telerik / Progress): Long-established HTTP debugging proxy for Windows (and Fiddler Everywhere cross-platform), directly competing with Charles for the same web and API debugging workflows. Same core proposition — capture, inspect, and modify HTTP/HTTPS traffic — with a subscription pricing model that contrasts with Charles' one-time license.
• Proxyman: Native macOS-first HTTP debugging proxy with a modern UI, scripting, and active feature development; targets the same individual developer use cases as Charles but with a Mac-native experience and subscription pricing.

Others

• Charles for iOS direct competitors (e.g., HTTP Catcher, Proxyman iOS): Category-level peer reference for iOS-native HTTPS debugging apps on the App Store (e.g., HTTP Catcher, Proxyman iOS) that compete with Charles for iOS in the mobile developer debugging niche.

Broad incumbents

• Chrome DevTools: Browser-native network inspection, throttling, and request editing built into Chrome. The most widely used free alternative to Charles for web developers, with progressively expanding capabilities that pressure Charles' paid value proposition.
• Wireshark: Industry-standard open-source network protocol analyzer operating at layers below HTTP. Overlaps with Charles on traffic capture and inspection but serves a broader, lower-level audience including network engineers and security analysts.
• Burp Suite (PortSwigger): Web security testing platform built around an intercepting proxy at its core. Overlaps with Charles' HTTPS interception and request editing capabilities, but is positioned for security professionals and penetration testers rather than general web/mobile developers.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks5 records

Key highlights6 records

Customer concentration

• Xx.com/charlesproxy

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Charles