Requestly started in 2014 as a small Chrome extension for rewriting HTTP headers and has grown into a full debugging suite used by 200,000+ developers worldwide. After being acquired by BrowserStack in 2023, the project doubled down on open-source foundations — the core remains MIT-licensed and the GitHub repo crossed 6,600 stars in 2026 — while the commercial tier now covers team collaboration, SSO, and larger session-replay quotas. The pitch is simple: a single browser extension and desktop app that replaces half a dozen scattered network tools with something that teams can actually share across.
Under the hood, Requestly bundles four tightly integrated surfaces. The HTTP interceptor rewrites headers, redirects URLs, injects scripts, modifies response bodies, and delays requests — all configurable through a clean rule builder and all without shipping code. The API client competes head-to-head with Postman and Insomnia, offering collections, environments, and scriptable tests with a much lighter footprint. A mock server lets developers stand up fake endpoints with templated responses in seconds, and the session replay feature captures full network + console + DOM state for bug reports that engineers can actually reproduce. The whole thing runs as a Chrome, Firefox, and Edge extension plus optional desktop app.
The sweet spot for Requestly is the frontend or QA team that spends real time wrestling with flaky third-party APIs, staged rollouts, and hard-to-reproduce production bugs. Instead of juggling Charles Proxy, Postman, a homegrown mock server, and a Loom video of what went wrong, a Requestly user ships one shareable rule or session that teammates can replay exactly. It does not try to be a full API observability platform — there is no long-term trace retention, no service-level SLO tooling, no distributed tracing — but for the client-side debugging loop, the breadth of features and the BrowserStack pedigree make it one of the most practical choices in 2026.
