AddressSanitizer (ASan) is a tool that finds buffer overflows (in stack, heap and globals) and use-after-free bugs in C/C++ programs. ThreadSanitizer (TSan) finds data races in C/C++ and Go programs. MemorySanitizer (MSan) is a work-in-progress tool that finds uses of uninitialized memory (C++). These tools are based on compiler instrumentation (LLVM and GCC), which makes them very fast (e.g. ASan incurs just 2x slowdown). We will share our experience in huge scale testing using these tools.