December 2025 Summaries

Trigger.dev has secured a $16 million Series A funding round led by Standard Capital, with participation from notable investors like Y Combinator and Rebel Fund, to enhance its platform that supports over 30,000 developers in creating production-grade AI agents and workflows. The company focuses on simplifying the construction of reliable AI systems by handling essential functions such as reliability, scaling, and observability, allowing developers to innovate efficiently. With the new funding, Trigger.dev plans to introduce advanced observability features, faster run starts using MicroVMs, and increased third-party integrations, while expanding its product offerings to address common challenges in AI agent development. The company is actively recruiting engineers who are passionate about open-source technology and interested in joining a US-style startup based in Europe.

Between November 28 and December 1, 2025, intermittent failures occurred during the ingestion of OpenTelemetry trace data into a ClickHouse server due to a partition key design flaw that created numerous tiny data parts, overwhelming the server’s merge capacity. The problem was traced back to the use of a partition key based on the start time of tasks rather than the time data was received, which led to difficulties merging old and new data parts efficiently. Despite the incident affecting the observability data, task execution remained unaffected. The resolution involved creating a new table with a corrected partition key, scaling the infrastructure, and implementing fixes to prevent late-arriving events from creating parts in old partitions. Lessons learned emphasized the importance of partitioning by insertion time to avoid late-arriving data issues and highlighted the need for comprehensive testing that includes long-running tasks and edge cases.