DR-SIM

Test resilience by simulating backend failures in web applications.

DR-SIM answers a question that is expensive to answer any other way: when one of the services behind your web application stops responding, does the rest of the app stay usable? It interrupts the backend calls you choose — only in your own browser, only while you have it switched on. The server is never touched, no data is changed, and no other user is affected. HOW IT WORKS Add the domain your application pulls data from. Open the page and the panel fills with a live inventory of every endpoint the page calls. Switch the simulation on and requests start failing according to your rules. The typical loop: set the default behaviour to "Block" so everything you have not allowed returns a fault, reload, see what breaks, then allow the endpoints the page genuinely needs — one click from the failure list. When the loop settles you know exactly what that page depends on. WHAT YOU GET • A live inventory of every endpoint each page calls, with call counts, status codes and timings • Realistic failures: a 503 response with a body you control, a network error, or a request that never answers until it times out • Per-endpoint rules with a single Allowed/Blocked switch • Path normalization, so /orders/8842/detail and /orders/9110/detail count as one endpoint • Shareable profiles: export your setup as a file, a teammate imports it and runs the same test • Reports in Markdown (for a ticket) or JSON (for tooling) • English and Turkish interface PRIVACY DR-SIM sends nothing anywhere. Everything stays in your browser's local storage. Request headers and bodies are not recorded at all by default; if you turn recording on, sensitive fields such as authorization headers, cookies and tokens are masked before they are written. PERMISSIONS The extension ships with no host permissions. Access to a site is requested at the moment you add its domain, in your own click context, and only for that domain. Built as a developer and QA tool for disaster recovery drills and resilience testing.