Balancers and Ports · 3 November 2026

Target weights and failover

Each entry in spec.targets accepts weight (1 to 1,000, default 1) and backup (default false). When targets have different weights, each request (or, for a port, each connection) goes to a target with a probability of its weight over the sum of the weights; when weights are equal, it goes to the target with fewer requests in flight of two chosen at random. On a balancer, a backup target receives requests only while no other target is healthy and has capacity; on a port, it receives connections only while every other target's sandbox is stopped or deleted. Available in every SDK.