Slack Engineering

Slack EngineeringJun 11, 202614 readmid

Agentic Testing: Where Agents Fit in the E2E Testing Stack

This article analyzes the efficacy of agent-driven end-to-end (E2E) testing compared to traditional deterministic tests. Through over 200 experiments using the Playwright MCP, CLI, and LLM-generated scripts, the authors evaluate the reliability, cost, and execution time of goal-oriented agent testing. They conclude that while traditional tests remain essential for CI, agentic testing provides a valuable layer for exploratory and complex behavior validation.

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Slack EngineeringMay 5, 202616 readmid

From SSH to REST: A Security-Driven Modernization of Slack’s EMR Data Pipelines

Slack migrated over 700 production data pipeline jobs from an SSH-based execution model to a REST-based architecture to improve security and infrastructure modularity. By replacing direct SSH access to EMR master nodes with a standardized API-driven approach, the team eliminated technical debt, resolved resource contention, and unblocked their transition to Kubernetes-based orchestration.

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Slack EngineeringMar 31, 20265 readmid

From Custom to Open: Scalable Network Probing and HTTP/3 Readiness with Prometheus

Slack addressed an observability gap during their HTTP/3 migration by extending the Prometheus Blackbox Exporter to support QUIC. By integrating the quic-go library into the exporter's existing architecture, the team enabled client-side probing of HTTP/3 endpoints to monitor performance and regressions.

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