> For the complete documentation index, see [llms.txt](https://docs.acymailing.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.acymailing.com/old/developers.md).

# Developers

- [AcyMailing 5 Developer Documentation](https://docs.acymailing.com/old/developers/acymailing-5-developer-documentation.md)
- [Customize the way the content inserted in emails by plugins](https://docs.acymailing.com/old/developers/customize-the-way-the-content-inserted-in-emails-by-plugins.md)
- [Conditional display](https://docs.acymailing.com/old/developers/conditional-display.md)
- [Multiple queue system](https://docs.acymailing.com/old/developers/multiple-queue-system.md)
- [External subscription form](https://docs.acymailing.com/old/developers/external-subscription-form.md)
- [Subscription via URL](https://docs.acymailing.com/old/developers/subscription-via-url.md)
- [Fabrik Form and AcyMailing](https://docs.acymailing.com/old/developers/subscription-via-url/fabrik-form-and-acymailing.md)
- [ChronoForm and AcyMailing](https://docs.acymailing.com/old/developers/subscription-via-url/chronoform-and-acymailing.md)
- [RSForm!Pro and AcyMailing](https://docs.acymailing.com/old/developers/subscription-via-url/rsform-pro-and-acymailing.md)
- [BreezingForms and AcyMailing](https://docs.acymailing.com/old/developers/subscription-via-url/breezingforms-and-acymailing.md)