osTicket

What is osTicket

osTicket is a widely-used open source support ticket system. It seamlessly integrates inquiries created via email, phone, and web forms into a simple, easy-to-use, multi-user, web-based customer support platform. Built in PHP and released under the GPL-2.0 license, it has been in active development for over a decade and is one of the most popular self-hosted alternatives to commercial help desk suites like Zendesk and Freshdesk.

Key features

• Unified ticket queue: Every customer request — whether it arrives by email, web form, phone (via integration), or API — lands in a single thread per user, where agents can reply, add internal notes, and collaborate with the rest of the team.
• Ticket filters and auto-responses: A flexible rules engine lets you route tickets to specific departments, assign priorities, trigger auto-responses, and escalate issues without writing code.
• Help topics and custom forms: Build per-department intake forms that capture the exact fields you need (product, version, environment, attachments) before a ticket is even opened.
• SLA plans and reporting: Track response and resolution times against service-level agreements, and measure team performance with built-in reports on ticket volume, agent load, and customer satisfaction.
• Extensibility: A plugin and theme system, plus a REST API and email piping, makes it straightforward to integrate osTicket with existing CRM, billing, or monitoring tools.

Self-hosting and how it compares

osTicket runs on a standard LAMP stack (Linux, Apache, MySQL/MariaDB, PHP) and is straightforward to deploy on a small VPS, in Docker, or behind a reverse proxy. Compared to Zendesk or Freshdesk, you avoid per-agent monthly fees and keep full control of customer data, but you do take on the responsibility for updates, backups, and uptime. For teams that want a capable, battle-tested help desk without the SaaS price tag, osTicket is the default open source choice.