Eiffel was designed by Bertrand Meyer and first released in 1986 with built-in design by contract.
Meyer developed Eiffel at Interactive Software Engineering, later known as Eiffel Software. The language was created to support reliable, maintainable object-oriented software, especially systems where correctness and long-term maintenance mattered.
Its signature idea is design by contract. Classes can specify preconditions for routines, postconditions describing results, and class invariants that should remain true. These assertions make software requirements explicit and can be checked during development or execution.
Eiffel influenced later approaches to software verification and contract-based programming. It is sometimes mistaken for Ada because both are associated with disciplined engineering, but Eiffel has a distinct object-oriented design and a different contract model. The language also introduced widely discussed ideas such as covariance in inheritance.