Jepsen aims to improve the safety of distributed databases, queues, consensus systems, etc. We maintain an open source library for safety testing, and publish free, in-depth analyses of specific systems. In each analysis we explore whether the system lives up to its documentation’s claims, file new bugs, and suggest recommendations for operators. In addition to paid analysis, Jepsen offers technical talks, training classes, and consulting services.
Jepsen pushes vendors to make accurate claims and test their software rigorously, helps users choose databases and queues that fit their needs, and teaches engineers how to evaluate distributed systems correctness for themselves.
Recent research, analyses, and announcements.
The latest Jepsen talk, “Jepsen 18: Serializable Mom”, is now available on Youtube. This talk was presented on June 20, 2025, at Systems Distributed in Amsterdam. It covers Bufstream 0.1.0, Amazon RDS for PostgreSQL 17.4, and TigerBeetle 0.16.1.
Jepsen and Capela, Inc worked together to test early builds of Capela, an unreleased distributed programming environment. Our analysis found twenty-two issues, including four problems in Capela’s programming language semantics, fourteen crashes or non-fatal panics, severe performance degradation after roughly a minute of operation, and three safety issues: partitions ignoring their initial values, sporadically vanishing, and losing committed writes. Capela has fixed two of the language issues—the others remain under investigation.
Kaivalya Apte interviewed Kyle Kingsbury for The GeekNarrator Podcast. We talk about common bugs in distributed systems, type I vs type II errors, ensuring correctness in Jepsen itself, LLMs, experimental techniques, formal verification, and more.
Jepsen’s 17th conference talk, “ACID Jazz”, is now available on YouTube. This talk was presented at Antithesis’ BugBash conference, in Washington, DC, and covers research on MySQL 8.0.34, Datomic Pro 1.0.7075, and Bufstream 0.1.0.
Antithesis and Jepsen are proud to present a glossary for distributed systems reliability. We hope this will be helpful for engineers, testers, and students!