Simon Willison’s Weblog

Subscribe

Friday, 9th January 2026

Fly’s new Sprites.dev addresses both developer sandboxes and API sandboxes at the same time

Visit Fly's new Sprites.dev addresses both developer sandboxes and API sandboxes at the same time

New from Fly.io today: Sprites.dev. Here’s their blog post and YouTube demo. It’s an interesting new product that’s quite difficult to explain—Fly call it “Stateful sandbox environments with checkpoint & restore” but I see it as hitting two of my current favorite problems: a safe development environment for running coding agents and an API for running untrusted code in a secure sandbox.

[... 1,560 words]

2026 » January

MTWTFSS
   1234
567891011
12131415161718
19202122232425
262728293031