Inside Replit’s New Sandbox Engine, Part 1: The Path to MicroVMs
How Replit rebuilt its sandbox engine with microVMs for stronger isolation, bottomless storage, and fast startup across hundreds of millions of projects.
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Security advisory: Make managed cloud environments the default for AI agents
Why autonomous AI agents need dedicated, organization-controlled environments with independently enforced security boundaries.
Agent Habitat Architecture
A proposed security architecture and maturity scale for agent habitats, covering identity, execution, permissions, data flows, approvals, and recovery.
Inside Replit’s Snapshot Engine: The Tech Making AI Agents Safe
An agent needs room to experiment and a way back when it gets things wrong. Inside the filesystem snapshots and database forks that make that possible.
So you suspect you have a memory leak...
Garbage collection doesn’t prevent every memory leak. How to confirm a leak, inspect a running program’s heap, and track down what won’t let go.
Dec 12 Incident Update: Secrets and repl.co Static Hosting Unavailable
How a storage configuration change disrupted Secrets and legacy static hosting in December 2023, and what we changed after the recovery.
Sep 29 Incident Update: Read-Only Repls
An incomplete storage build left some projects read-only on September 29, 2023. Our account of the incident, recovery work, and safeguards that followed.
Replit Storage: The Next Generation
Getting past the 1 GiB storage limit meant rethinking the filesystem underneath it. Inside the snapshot and copy-on-write design that made larger projects possible.
April 2 Potential GitHub Credentials Exposure
Our account of the April 2023 GitHub token vulnerability: who may have been affected, how we fixed it, and what users should check.
Worldwide Repls, part 2: Load balancing for fun (although not quite profit)
An off-the-shelf load balancer couldn’t route containers the way we needed. How we built an alternative and brought it into production.
Worldwide Repls, part 1: The Control Plane
Moving compute closer to users started with separating the control and data planes. Inside the infrastructure refactor that made global routing possible.
Escaping Dirty Pipe (a.k.a. CVE-2022-0847), mostly unscathed
How the Dirty Pipe Linux vulnerability affected Replit, what we did to address it, and why we found no evidence of successful exploitation.
Announcing File Persistence in Hosted Apps… for Everyone!
What it took to bring persistent files in hosted apps to everyone: a gradual rollout, better monitoring, and a few infrastructure optimizations.
Making new Python repls 100x faster to start up
Reinstalling packages at every startup made Python projects painfully slow. How a new template cut that wait and made room for larger dependencies.
Announcing File Persistence in Hosted Apps for Hackers
Hosted apps need to save files even when the editor is closed. How file persistence opened up uploads, SQLite databases, and more.