Esper vs Lenses

Esper is a language, compiler, and runtime for complex event processing and streaming analytics in Java and .NET. Its Event Processing Language extends SQL with expressions over events and time. The compiler turns EPL into bytecode that can be packaged in JAR files. Esper and NEsper embed inside Java or .NET processes rather than running as standalone servers. The in-memory runtime is described as memory-efficient and low-latency and does not require external storage or services. Adapters handle CSV, JMS, HTTP, Kafka, database, and socket input and output, with JMX metrics exposure. Queries can join event streams with web services and relational databases through SQL-query or method-invocation joins. Esper Enterprise Edition adds scale-out architecture with elastic scaling, load balancing, fault tolerance, and multi-datacenter support using Apache Kafka and Apache Zookeeper. Listed uses include business-process monitoring, financial applications such as fraud detection, network and application monitoring, and sensor networks. Esper 9.0.0 is listed under GNU GPL (GPL v2); commercial redistribution licenses are available. Production support has Bronze, Silver, and Gold levels, plus a Developer Seat for how-to questions.

Lenses describes its Operating Fabric as a platform for building, governing, and operating Kafka applications with engineers and AI agents. Users can discover streaming data across domains with SQL, prepare it for consumption, and deploy data streams independently. It connects to Confluent Platform, Confluent Cloud, Amazon MSK, Redpanda, and self-managed Apache Kafka, and can run in cloud, on-premises, or hybrid environments. Work interfaces include a Web App, VS Code Extension, Lenses MCP, and Lenses CLI. Lenses says OAuth 2.1 gives agents scoped, short-lived, revocable, and audited access. It also lists open-source Kafka connectors for systems including Amazon S3, Azure Event Hubs, GCP Storage, Cassandra, MongoDB, Redis, and Elasticsearch; the connectors are Apache 2.0 licensed and have enterprise support. The DevX Community Edition supports up to five free users, while SQL Studio supports up to two Kafka clusters. A trial key is available through the guided demo. Team Edition is listed from $4,000 per year and supports up to 15 users with SSO/SAML, RBAC, and Team Support.