Probe

Probe is a local HTTP/HTTPS debugging proxy and API client for inspecting app traffic, changing requests and responses, creating mocks, and automating requests. It can capture and decrypt traffic from phones, simulators, desktop apps, and terminal clients, displaying headers, bodies, and timing. Breakpoints let users pause requests or responses, edit their contents, then continue or abort them. Map Local can return a file or inline body for matching URLs; Map Remote can forward matching requests to another host. Visual flows can chain requests, extract values, check results, branch, and loop, and can run through the app, REST API, MCP, or headless CLI. The API client supports HTTP and GraphQL, collections, environments, authentication, and history, with cURL and Postman import and Postman v2.1 export. Probe also provides an MCP server for compatible clients and file browsing and transfers over several listed protocols. Its free plan costs nothing. HTTPS inspection requires installing and trusting Probe’s locally generated CA certificate on each device.

Probe combines traffic inspection, API client tools, mocking, and automation in one local tool. Its CA setup and Android app trust requirements are relevant when planning HTTPS inspection.

Probe suits developers who need to inspect mobile, desktop, or terminal traffic, work with APIs, or automate requests. It is available on Android, iOS, macOS, Windows, and through an API.

Probe is a local proxy and API workbench aimed at developers diagnosing network behavior across mobile, desktop, and terminal software. It is strongest for people who want capture, manipulation, mocking, and repeatable API workflows in one application rather than several narrowly focused utilities.

The free tier is unusually broad for core debugging, but HTTPS certificate deployment—especially on modern Android—can determine whether it fits your team’s workflow.

Overview

Probe intercepts HTTP and HTTPS traffic from iPhone and Android devices, simulators, desktop applications, and command-line clients. The interface exposes headers, bodies, and timing, giving developers the context needed to trace a failed call or compare client behavior. Because sessions can be saved, loaded, and exported, an investigation can be revisited instead of reconstructed from scratch.

Privacy-sensitive development benefits from Probe’s local design. Captured traffic and session data remain on the device, private CA keys stay there, and the product says it collects no analytics and requires no account. HTTPS decryption uses a locally generated certificate authority, so every device must install and trust that CA. Android 7 and newer accept user-installed CAs only for apps that explicitly opt in; teams debugging an Android app may therefore need a network-security configuration change before inspection works.

Key features

Breakpoints stop a request or response mid-flight. You can alter headers or bodies, then continue or abort the exchange, while breakpoint rules make recurring interventions practical. Replay is useful for reproducing a call without repeating the original app action, and WebSocket inspection extends coverage beyond ordinary request-response traffic.

Probe’s mapping tools address two different substitution jobs. Map Local answers matching URLs with a local file or inline body, which is suited to deterministic fixtures and offline UI states. Map Remote forwards matching traffic to another host, useful when a staging or compatibility endpoint must stand in for the original service. Both are listed for the Pro plan, so Free users should not choose Probe expecting the full mocking and routing set.

The API client handles HTTP and GraphQL, with collections, environments, authentication, and history. Import from cURL or Postman and export in Postman v2.1 format, making it easier to bring existing request libraries into the same workspace. Visual flows can chain calls, extract values, assert results, branch, loop, and run from the application, REST API, MCP, or a headless CLI. A built-in MCP server connects Claude Code, Cursor, Codex, and other compatible clients to traffic inspection, replay, mock management, and flow execution.

Probe also lists file browsing and transfers over SFTP, FTP/FTPS, S3, and WebDAV. Those integrations broaden its scope, but the core advantage remains the unified debugging and API workflow rather than file administration alone.

Pricing

Free — free. This plan includes HTTPS interception, iOS and Android debugging, request and response inspection, breakpoints with JavaScript scripting, collections, session save/load and export, and network throttling. It is a credible starting point for individual developers and small teams that need to inspect and modify traffic without a subscription.

Pro — custom pricing (coming soon). Pro includes everything in Free plus advanced scripting and automation, Map Remote and Map Local, team collection sharing, and priority support. It is the logical choice for groups that need shared request assets or sophisticated mocks, but the unpublished price makes budgeting impossible today. The Free tier gives up those collaboration and advanced mapping capabilities.

Platforms

Probe is offered on Android, iOS, macOS, Windows, and through its API. The desktop application supports macOS 12 or newer on Apple Silicon or Intel, and Windows 10 or newer. Device-by-device CA installation is an operational requirement for HTTPS inspection, not an optional convenience.

Who it's for

Choose Probe if you debug mobile or desktop applications, need to alter live exchanges to reproduce edge cases, or want API collections and automated flows beside captured traffic. Its local-only data handling is particularly appropriate for sensitive development environments. It is less suitable when Android apps cannot be changed to trust a user CA, when a team needs established shared workflows immediately, or when a published Pro price is required for procurement.

Pros and cons

• Pros: Broad Free coverage for interception, editing, scripting, throttling, and session portability.
• Pros: Local capture and CA-key storage reduce exposure of sensitive traffic and require no account.
• Pros: HTTP and GraphQL tooling, visual automation, MCP access, replay, and WebSocket inspection share one workflow.
• Cons: HTTPS setup must be repeated on each device, and Android 7+ apps may need explicit user-CA support.
• Cons: Map Local, Map Remote, advanced automation, team sharing, and priority support are reserved for Pro, whose price is not yet published.

Alternatives

Fluxzy is a better fit for Linux users or anyone wanting a free Community Edition with all features for personal use. HTTP Toolkit suits readers who prefer a web-enabled option and a Hobbyist tier with basic interception, breakpoints, and HTTP client tools.

Moni Proxy is worth considering when explicit free-plan quotas for mocks, rewrites, DNS overrides, and daily Compose requests match your needs. ProxyHawk offers a monthly plan with three devices and unlimited traffic for users who need that stated allowance on macOS, iOS, or Android.

Reqable is an alternative for Linux support and a Community plan with one device, 100MB storage, and capped rule counts. Rockxy is a Mac-focused open-source option under AGPL-3.0. Whistle is a free cross-platform proxy. Charles is the paid choice for readers who want a traditional licensed product with a free trial.

For a wider comparison, see Web Debugging Proxies.

Verdict

Probe is a strong recommendation for developers who want local traffic inspection, controlled request changes, API client features, and automation in one free starting point. Its decisive drawback is deployment friction: certificate trust must be configured per device, Android apps may reject user CAs, and the Pro price is still custom. Pick Probe for a privacy-conscious, integrated workflow; look elsewhere when effortless Android interception, Linux desktop support, or fully transparent team pricing matters more.