We present Linera, a blockchain infrastructure that aims to support the most demanding Web3 applications by providing them with predictable performance, security, and responsiveness at the Internet scale. To do so, Linera solves the blockspace scarcity problem by introducing a new, integrated, multi-chain paradigm built upon elastic validators. Linera puts users at the center of the protocol by allowing them to manage the production of blocks in their own chains—called microchains—for optimal performance. To help Web3 developers make the most of the Linera infrastructure, we have developed a rich, language-agnostic, multi-chain programming model. Linera applications communicate across chains using asynchronous messages. Within the same microchain, applications are composed using synchronous calls and ephemeral sessions (aka. resources). The initial SDK of Linera will target Rust programmers, thanks to the Wasm virtual machine. The Linera infrastructure is based on delegated proof of stake. It will ensure robust decentralization using state-of-the-art economic incentives and auditing at scale by the community.