Full Stack Developer required to take lead on ongoing project

I need an experienced full stack developer to help me develop the functional parts of a new website along with a body of php code including an API for a new national courier.

The resulting system will allow recipients of parcel deliveries to use the website to

- place orders for delivery services
- sign up for accounts
- manage their orders via their accounts
- pay using stripe/paypal interchangeably
- track their deliveries

The resulting system will allow senders of parcel deliveries to

- place orders for delivery services
- manage their shipments via their accounts
- upload csv files of shipments to their accounts
- download pdf shipping labels
- create shipments via an API
- track shipments via an API
- create collection requests via an API
- download shipping labels via an API

A great deal of the background code already exists, from other websites and systems I have developed, and a start has been made on the functional parts of the website. However, this project really needs a professional developer who is fully up to date with modern web technologies to ensure the resulting systems are robust, well documented, and work on all operating systems, devices, and browsers.

For an experienced developer, not having to learn on the job as I often do, I expect there to be work to fill around 50-100 hours. I would want to work quite closely with the developer over the course of the project, talking via skype and telephone every 1-3 days, setting small milestones as we go.

Please get in touch if you have experience of HTML, Bootstrap, CSS, Javascript, PHP, AJAX calls, curl, soap, and APIs.

Once the main body of work is done, there will be ongoing improvements and maintenance required.