With the ConstantContact SDK, developers can integrate Email marketing data services into software and applications. Authored by Elijah Gaiter, this resource uses GuzzlePHP, an HTTP client that intends to simplify HTTP requests. Installation can be manual or via composer. See the source documentation available at http://constantcontact.github.io/php-sdk/
Mailgun added a slew of new features to its email validation API including target mailbox validation, role-based address check, disposable mailbox, reporting, and rate limits. Additionally, Mailgun added the API under its existing SLA and has transitioned to a tiered, usage-based pricing model.
It's no secret that Facebook's Graph API and widgets have contributed a great to Facebook's success and never-ending permeation of the web as we know it. Looking to make a similar move, LinkedIn has recently expanded its own developer platform and LinkedIn API. The new LinkedIn tools aren't just aimed at developers. With just a couple lines of code, you can begin integrating LinkedIn in to your web page with a variety of plugins and widgets.