---
title: "Fly Answers Questions"
description: "Fly Answers Questions compiles responses about custom domains, configuration recovery, Turboku deployment, database latency, TLS termination, global databases, continuous deployment, and idle-app scaling. Fly allows multiple custom hostnames per application and automatically provisions Let’s Encrypt certificates after validation; a deleted fly.toml can be restored with flyctl config save -a , with -c supporting another filename. For Turboku, Heroku slugs run as containers in a nearby datacenter rather than at the edge, while region selection can reduce database latency and retain edge SSL termination. The service supports TLS-only termination up to HTTP/1.1, GitHub Actions deployment, Redis for local caching, and a replication system for distributing changes, while keeping one running instance for idle apps instead of scaling them to zero."
---

# Fly Answers Questions

[Fly.io](https://yomu.fyi/company/fly-io) · Mar 18, 2020

**Type:** Explainer

## Summary

Fly Answers Questions compiles responses about custom domains, configuration recovery, Turboku deployment, database latency, TLS termination, global databases, continuous deployment, and idle-app scaling. Fly allows multiple custom hostnames per application and automatically provisions Let’s Encrypt certificates after validation; a deleted fly.toml can be restored with flyctl config save -a , with -c supporting another filename. For Turboku, Heroku slugs run as containers in a nearby datacenter rather than at the edge, while region selection can reduce database latency and retain edge SSL termination. The service supports TLS-only termination up to HTTP/1.1, GitHub Actions deployment, Redis for local caching, and a replication system for distributing changes, while keeping one running instance for idle apps instead of scaling them to zero.

## Context

Questions about Fly are asked in many places on the web, but not everyone is present everywhere. The post gathers answers in one place and points to Fly’s Twitter account and Spectrum.chat forum for further questions.

## Approach / What changed

Uses a question-and-answer format to document Fly capabilities, configuration commands, deployment behavior, regional placement, TLS termination, database options, continuous deployment, and scaling decisions.

## Takeaways

- Validated custom hostnames can be added in any number to an application, with Let’s Encrypt certificates obtained automatically.
- flyctl config save -a retrieves the last-used application configuration and saves it as fly.toml; -c specifies a different filename.
- Fly keeps one instance running for completely idle apps rather than scaling to zero, avoiding regular cold starts while retaining Anycast IP and edge TLS benefits.

**Tags:** [Deployment](https://yomu.fyi/topic/deployment), [Fly](https://yomu.fyi/topic/fly), [TLS](https://yomu.fyi/topic/tls)

- Source: [Fly.io](https://fly.io/blog/fly-answers-questions)
- Source URL: https://fly.io/blog/fly-answers-questions
- Ingested by Yomu: 2026-09-02T11:58:14.680Z

[Read original post](https://fly.io/blog/fly-answers-questions)