Co-founder and CTO of HelloSign here. Sorry to hear that OP's bug reports weren't taken seriously. Good tech support is a must for mission critical APIs. At HelloSign we take great pride in our API and our tech support. Rather than outsource support or rely on less technical people, we have our developers directly support the API they built. So when you give our API a try, I encourage you to check in with one of our…
One of the best parts of working with Hellosign is their amazing tech support team. They are incredibly responsive (and nice!), and have helped us troubleshoot issues on many occasions. We are on a first name basis with these guys, and would recommend working with them!