tcplocal

Tcplocal is a software abstraction and library for managing local TCP connections on a single host, designed to enable low-latency inter-process communication between services running on the same machine. It provides a local transport that mirrors standard TCP semantics while routing traffic through optimized locally scoped channels, typically via the loopback interface or a local IPC mechanism beneath a TCP-like API.

Core concepts include connection management, framing, and retry semantics. Implementations vary by platform but commonly offer non-blocking I/O, connection pooling, and support for simple message framing or request/response patterns. The API usually presents a client side for connecting to a local endpoint and a server side for accepting local connections, with an emphasis on reducing overhead associated with cross-host TCP traffic while preserving familiar programming models.

Usage scenarios center on microservices, components, or test environments that need realistic TCP-style communication without the cost of network travel. Tcplocal is particularly advantageous when services are co-located on the same host and require predictable latency, deterministic throughput, or easier deployment than configuring real network paths. It is not intended for inter-machine communication; for multi-host communication, conventional TCP sockets over a network are typically used.

Design considerations include security, as local IPC channels must enforce access controls to prevent unauthorized local access. Portability and compatibility across operating systems can influence API design, especially in environments with different I/O models. Some implementations may offer optional encryption or integrity features for end-to-end security, even within a single host.

Related concepts include TCP, loopback networking, Unix domain sockets, and inter-process communication.