S2

S2 provides a serverless API designed for managing unlimited, durable, real-time data streams, positioning streams as a fundamental cloud storage primitive. The platform addresses the needs of applications that require reliable, scalable event streaming and real-time data handling, offering append and read operations with strong consistency guarantees. S2 is described as bridging the gap between moving data and static object storage, enabling developers to treat streams as first-class web resources.

Key features include atomic appends to the tail of a stream, durable ordering of records on object storage before acknowledgment, and efficient reads from any point in a stream—by sequence number, timestamp, or offset. S2 supports reactive, resumable, and live update reads, with real-time tailing available via Server-Sent Events (SSE) or HTTP/2 sessions. The platform offers granular access controls, allowing the issuance of access tokens scoped by resource and permitted operations, with no limit on the number of tokens and support for automatic expiration and revocation. S2 provides a command-line interface (CLI) for managing basins (similar to buckets), streams, and access tokens, as well as for streaming append and read sessions.

SDKs are available for TypeScript, Go, Rust, and Python, and developers can interact with S2 streams using REST APIs from both backend and client-side code. The system is built for elasticity and scale, supporting unlimited streams that can grow indefinitely, with data stored in object storage to optimize costs. S2 is engineered for high throughput, supporting up to 100 MiBps writes per stream and large-scale read fanout. Performance metrics include append latencies under 40ms and producer-to-consumer times under 50ms in the same region (p99). The infrastructure is implemented in Rust and is tested with deterministic simulation for reliability and memory safety.

Security and compliance are emphasized, with SOC 2, HIPAA, and GDPR compliance, as well as organizational controls for data protection. S2 is suitable for developers building event-driven systems, real-time applications, collaborative and multiplayer experiences, agent event sourcing, and large-scale broadcasting. An open-source, self-hosted version called s2-lite is also available. No credit card is required to start using the service, and users can create their first stream in seconds.