Hi,
I have worked on huge projects like yours.
I am full stack developer having 6 plus years experience in php/web development. In my career, I have worked on multiple frameworks and cms in php like Magento, Wordpres, Codeigniter, Yii, Laravel and Opencart etc.
Recently completed a project related IT services company for my client in Laravel, some of its features are given below.
1). HRM
a).Leaves management system(short/full leaves and sick/casual/annual leaves).
b).Managing employees HR related data, annual pay raises etc.
c).Implemented Google calander API.
2). CRM
a).Customers management
i).Multiple contacts for each customer.
ii).Multiple locations for each customer.
iii).Vendors attachment for each customer.
iv).Devices and their configuration settings management.
v).Contracts management.
vi).Invoices management, imported from zoho invoices through API.
b).Ticket management
i).Email based, with gmail API.
ii).New ticket notification over SLACK, through API.
c).File manager for each customer.
3). APIs and libraries used.
a). Gmail (Events and calander).
b). Zoho (invoices and customers).
c). Slack (ticket module activities notifications).
Demo linka and credentials will be provided on demand.
Please feel free to contact for further detail discussion.