Definition
Plain language
Throwing huge amounts of random or malformed input at a program to see what makes it crash.
As stated in the literature
An automated testing technique that feeds randomized or mutated inputs to a target to surface crashes and vulnerabilities; weak at finding bugs requiring precise structured inputs or specific thread interleavings.
Also called: fuzzer, fuzzers, fuzz
Why it matters: It uncovers crashes and security holes automatically, though it struggles with bugs that need very specific, well-structured inputs to trigger.
For example, a tool feeds a photo app thousands of garbled image files in a row to see which one makes it crash.
Heard on the show
“The question of how to make rich, mutating state cheaply branchable shows up in serverless cold-starts, in fuzz testing, in time-travel debugging, and now in agent search.”Episode 068 — The OS Trick That Makes Tree Search Practical for Coding Agents