Invoice Ninja is a free, open-source solution for invoicing & billing customers. With Invoice Ninja, users can easily create and send professional invoices from any internet-enabled device. Clients can print invoices or download them as pdf files as well as pay online from within the system.
Mailchimp is an extensive email marketing tool, and probably the most versatile out there! Targeted campaigns, newsletters, and automated messages together with a broad range of excellent and customizable templates and pre-made campaigns will make this a breeze!
PieSync integrates Mailchimp with other apps for an automatic 2-way subscribers sync. Every time a subscriber is added in Mailchimp, or it gets updated, it is automatically synced with the other app, and vice versa - eliminating import/export!
Typically, CRM's only support one-way, manual pushes of contacts into Mailchimp lists. In contrast, PieSync syncs in real time, all the time, and it goes 2-way, supporting tags & groups!