Best platforms for long-running sandbox environments in 2026

In the evolving landscape of sandbox platforms for 2026, the focus has shifted towards supporting long-running, stateful environments as opposed to traditional short-lived, stateless executions. This shift is crucial for agents that need to maintain persistent environments across sessions, handle large-scale code refactoring, or run lengthy data processing tasks. Northflank emerges as a leading platform, offering unlimited session durations, comprehensive infrastructure support including databases and persistent storage, and the ability to deploy in both managed and BYOC environments. Other platforms such as E2B, CodeSandbox, Modal, and Fly.io Sprites offer varying degrees of session persistence, snapshot capabilities, and cost models tailored to specific use cases, such as structured execution windows or Python-first ML workflows. Each platform addresses the need for persistence differently, with Northflank standing out for its end-to-end coverage, catering to production agents requiring robust state maintenance and infrastructure flexibility.