Bartosz Blimke's wroclove.rb 2024 talk — his second public presentation about WebMock (the first was in London 15 years earlier) and his first presentation in 14 years. Covers what WebMock is (stubbing HTTP requests and verifying HTTP calls), its origin story (inspired by FakeWeb's limitations, created during a one-day hackathon at New Bamboo), adoption numbers (250M+ downloads, ~4,000 GitHub stars, 260+ contributors, ~8,000 dependent gems), and features (HTTP-client-agnostic DSL, stub–execute–verify paradigm borrowed from Mockito, callbacks used by VCR, stubbing timeouts/basic auth/curl responses, helpful stubbing-instructions errors). Explains why mocking HTTP is useful: tests run offline, misconfigured production credentials can't fire destructive requests, tests are fast and stable, all status codes can be simulated, and development can proceed without third-party API access. Walks through how HTTP clients in Ruby generally work, then dissects WebMock internals: stub request creates a request-stub object (pattern + fake responses) in a global stub registry; callbacks go in a global callback registry; adapters subclass each HTTP client and monkey-patch the handle_request method to build a request signature, register it, match against the stub registry, return fake responses (or raise with stubbing instructions when real connections are blocked by default), run callbacks and middleware; constant replacement swaps the original client class for the instrumented copy so changes can be reverted. Ends with a personal tribute to the New Bamboo team ('Bambinos') and to the wroclove.rb organizers, emphasizing that the most important thing for a developer's growth is the people they work with. Q&A: contract testing isn't built into WebMock but scope-of-stub-validation is on Blimke's mind (global registries make scope hard today); there is no automated system for tracking HTTP-client changes — tests run against the latest gem versions, and incompatibilities are usually reported as issues.