Upstash is a serverless data platform made by Upstash, Inc. Serverless means the customer runs and sizes no servers: the service grows with traffic and is billed per request. Its main product is Upstash Redis, a hosted Redis database. Redis is an in-memory key-value store: it keeps data in RAM, so reads and writes finish in well under a millisecond, and it is often used for caching, rate limiting, queues and session storage.
A program connects over the standard Redis protocol (TCP) or over a REST API on HTTP; the HTTP option suits serverless and edge functions, because it needs no connection pool. Data is persisted, and a database can be replicated across regions for fast reads near users. Existing Redis commands and client libraries work. The platform also offers Vector (a vector database for similarity search), QStash (messages and scheduled jobs over HTTP), Workflow (long-running serverless functions), Box (cloud containers for AI agents) and Blob (file storage).
Upstash is a hosted service. Redis has a free tier, pay-per-request pricing, and fixed monthly plans for steady loads.