Infinity is a Rust framework for building massively concurrent agentic systems, light enough to fit 75k agents in the memory of a Raspberry Pi. Infinity does for agents what async did for threads: instead of blocking on slow tools, Infinity agents run them concurrently, yield while they wait, and cost nothing until the next event arrives.
let system = AgentSystemBuilder::new_local(
InMemoryConversationStore::new(),
InMemoryStateStore::new(),
StaticModel::new(provider, "claude-sonnet-4-5").await?,
)
.start();
let mut thread = system.thread_builder().launch().await;
thread.send_user_text("Write a haiku about Rust").await?;
while let Some(event) = thread.recv().await {
println!("{event:?}");
}Between turns, an agent is pure data, just its conversation history with no task, no stack, and no open connection, so a waiting agent hibernates for free and wakes on the next message. The same agent code runs unchanged in a resident process on your laptop and on serverless platforms like AWS Lambda, where scale to zero is the default.
Get started today at infinity.hydro.run!
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Infinity Runtime: Build your first agent with the quickstart, see how yielding turns and hibernation work in the architecture guide, and deploy on AWS Lambda with the included CDK constructs.
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Reactive Agent Protocol (RAP): Serve tools over the network without holding a connection open: results and subscription events are delivered whenever they are ready, even to agents that currently have no process at all. Existing MCP servers run unchanged through a compatibility layer, and anyone can implement the open specification.
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Infinity Code: A coding agent built on the runtime for concurrent work: it runs builds and tests in the background while their output streams in, edits in parallel threads with stacked sandboxes, and hands you each result as a diff to review.