HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
MockServer - Easy mocking of any system you integrate with via HTTP or HTTPS.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
HttpMaster - HttpMaster is a professional software tool for testing and debugging HTTP applications, primarily aimed at REST API applications and web services.
Marketo - Marketo's powerful marketing automation software helps marketers master the art & science of digital marketing to engage customers and prospects.
Hoppscotch - Open source API development ecosystem