This paper introduces ARCtimer, a framework for modeling, generating, verifying, and enforcing timing con-straints for individual self-timed handshake components. The constraints guarantee that the component’s gate-level cir-cuit implementation obeys the component’s handshake protocol specification. Because the handshake protocols are delay-insensitive, self-timed systems built using ARCtimer-verified components are also delay-insensitive. By carefully considering time locally, we can ignore time globally. ARCtimer comes early in the design process as part of building a library of verified components for later system use. The library also stores static timing analysis (STA) code to validate and enforce the com-ponent’s constraints in any self-timed system built using the library. The library descriptions of a handshake component’s circuit, protocol, timing constraints, and STA code are robust to circuit modifications applied later in the design process by technology mapping or layout tools. In addition to presenting new work and discussing related work, this paper identifies critical choices and explains what modular timing verification entails and how it works.