---
title: "Readiness Probes"
description: "1 posts about Readiness Probes, summarised, each linking to the original."
---

# Readiness Probes
> 1 posts about Readiness Probes, summarised, each linking to the original.

## Articles

### [Unpacking sandbox startup latency: why started ≠ ready](https://yomu.fyi/post/unpacking-sandbox-startup-latency-why-started-ready.md)
- Company: [Modal](https://yomu.fyi/company/modal.md)
- Published: Jun 22, 2026
- Type: Problem & solution

Sandbox startup benchmarks measure container boot time, but in production application-level initialization after boot dominates, making container boot the smallest variable. Modal defines a lifecycle with events Created, Scheduled, Started, and Ready, where Ready indicates completion of tasks like git pulls or dependency installs. The gap between Started and Ready can be multiple seconds, directly affecting user-perceived latency for coding agents needing cloned repos and running services. To reduce perceived latency, Modal recommends warm pools that pre-initialize sandboxes using a Queue, combined with Directory Snapshots for per-project customization without rebuilding the environment. Readiness Probes, now generally available, allow defining a shell command that exits 0 or a TCP port that accepts connections, with wait\_until\_ready() blocking until the sandbox is truly ready, simplifying warm pool producer code and providing dashboard events for observability.