Mockadabra - API Mocking & Request Interceptor

Turn API chaos into usable magic. Mock API responses, simulate errors and test frontend apps without backend changes.

MOCKADABRA Turn API chaos into usable magic. Stop waiting for the backend. Start testing what matters. Mockadabra is a browser-based API mocking extension built for frontend developers and QA engineers. Intercept, mock, and modify HTTP responses directly in Chrome, without changing your application code or backend. Whether you're developing a new feature, reproducing a bug, or testing an edge case, Mockadabra gives you control over the API responses your application receives. WHAT YOU CAN DO • Mock HTTP responses Replace Fetch and XMLHttpRequest (XHR) responses with custom JSON, text, status codes, and headers. • Test failure scenarios Simulate API errors, network failures, empty responses, and response delays to see how your application behaves when things go wrong. • Modify real API responses Keep working with your existing backend while changing selected response data for development and testing. • Control mocking directly from the popup Enable or disable mocking for the current tab, switch the tab's project and environment, toggle rules, and select response scenarios without opening the full Dashboard. • Quickly edit mock responses Edit the body of existing mock responses (JSON or plain text) directly from the popup. Save and continue testing: the next matching request uses the updated response without reloading the page. For larger responses or advanced settings such as status codes, headers and delays, use the full Dashboard editor. • Organize everything into projects Separate mocks by application, feature, or testing workflow. Organize rules and environments without fixed limits on their total number. • Switch between response scenarios Define multiple responses for a rule and switch between them without constantly editing your mock data. • Match requests precisely Target requests using URL patterns, HTTP methods, headers, query parameters, and request-body conditions. • Use variables and environments Reuse values across configurations and adapt your mocks to different development and testing environments. • Import existing mock configurations Bring in compatible HTTP mock rules from external JSON files. Mockadabra analyzes the file, suggests conversion settings, and lets you review the rules before creating a new project. Unsupported configurations are identified rather than silently converted. • Back up and restore your work Export native Mockadabra backups, restore your configurations, and share setups with teammates. BUILT FOR REAL DEVELOPMENT WORKFLOWS Backend endpoint unavailable? Mock it. Need to reproduce a specific bug? Create the exact response. Testing empty data, server failures, or slow responses? Configure a scenario. Need to adjust a mock response while testing? Open the popup, make your changes, and continue. Moving between applications or testing environments? Keep your configurations organized and switch when needed. Migrating existing mocks? Import compatible rules instead of recreating everything manually. LOCAL-FIRST. YOU STAY IN CONTROL. Your projects, rules, variables, and mock responses are stored locally in your browser. No account or cloud synchronization is required. Mockadabra operates on websites you explicitly authorize. Requests that aren't mocked may still reach their original servers. FREE WITHOUT ARTIFICIAL RULE LIMITS Create projects, environments, and rules without fixed numerical limits on their total count. Build the testing setup you need without worrying about arbitrary rule caps. Mockadabra. Turn API chaos into usable magic.