osTicket is a widely-used PHP ticket system which is also believed to be the best open source supoort ticket solution. It seamlessly integrates inquiries created via email, phone and web-based forms into a simple easy-to-use multi-user web interface. Manage, organize and archive all your support requests and responses in one place while providing your customers with accountability and responsiveness they deserve.

How osTicket helps you:
- Users create tickets via your website, email or phone
- Incoming tickets are saved and assigned to agents
- Agents help your users resolve their issues

Features of osTicket:
- Web and Email Support: Tickets can be created via email, online forms or phone (created by staff). Flexible configuration and mapping.
- Auto Response: Automatic reply that is sent out when a new ticket is opened or a message is received. Customizable mail templates.
- Canned Replies: Predefined responses for frequently asked questions.
- Internal Notes: Add internal notes to tickets for staff.
- Help Topics: Configurable help topics for web tickets. Route inquiries without exposing internal departments or priorities.
- Alerts and Notices: Staff and clients are kept up to date with email alerts. Configurable and flexible settings.
- Role-based Access: Control staff's access level based on groups and departments.
- Assign & Transfer Tickets: Assign tickets to a staff and/or department.
- No signup Required: No user account or registration required for users (ticket ID/email used for login).
- Support History: All support requests and responses are archived.

System Requirements:
- PHP 4.3 or Higher
- MySQL 4.4 or Higher