Each month we get lots of tweets to our main @SendGrid account from users, potential users, and people on the hunt for free schwag. Many of these tweets are answered directly by our team of Developer Evangelists but we thought that some of the answers to those questions might be of interest to more of you, so we’re going to try and highlight a few interesting ones each month and give those answers a more permanent home. Here’s a selection from the past few weeks and their answers: Question 1: Subusers @SendGrid question: can subusers have their own unsubscription and spam report lists to the main account? — ⭐ Daniel Lucraft (@danlucraft) November 28, 2013 Answer: Yes, each subuser under any master account also gets it own unsubscribe and spam report lists. They have their own endpoints on our API so you can work with data for a subuser directly. For more information, take a look at the documentation for Subuser Spam Reports and Subuser Unsubscribes. Question 2: Playing with other APIs @bwest Question: how easy would it be to implement a bus-schedule-notification system for Boulder transit using @sendgrid, similar to ATX’s? — Paige Bailey (@DynamicWebPaige) November 19, 2013 SendGrid’s Brandon West replies to the positive: @DynamicWebPaige @SendGrid Should be pretty straightforward; RTD data http://t.co/HvGC2YZysn + parse webhook http://t.co/gHErI3Qb9c — Brandon West (@bwest) November 19, 2013 It would be pretty simple to throw together a quick hack for this. Denver’s RTD data is in the GTFS (General Transit Feed Specification), that is well documented by Google because they use it for their transit updates on Google Maps. In this instance, the data is offered as a downloadable ZIP file. The contents of which can be shoved into a light database and polled for specific updates which would then be sent out via email. Question 3: Newsletter limitations @SendGrid Are there any limits to the number of newsletters and lists you can keep in the system? — Jake Mauer (@jakemauer) November 19, 2013 Answer: Nope, go crazy. There are no limits on the amount of lists or the size of those lists, although it is worth noting that if you are trying to retrieve all the emails on a specific list via the API, and that list has thousands upon thousands of subscribers, it will take longer to retrieve and you should allow for this. If you’re uncertain about how that might affect performance in your application then you can run some queries via our excellent load testing service, loader.io, to see how best to deal with any bottlenecks this might cause. Question 4: Marketing or transactional? @SendGrid hey! 🙂 I’m sending marketing emails but don’t need an interface, (got my own infrastructure). Do I go for a “transactional” plan? — Adam Tal (@adamtal) November 25, 2013 Answer: Yes, you can go with a transactional plan. If you’ve got your own interface for list management, handling unsubscribes and creation of the emails themselves then you’ve got it in the bag, all you need is the ability to send those emails, and our SMTP API will be fine for this. More questions? As ever, if you’ve got a question about using SendGrid then our documentation should always be your first port of call. Our docs are also open source, so if you want to contribute to any aspect of it then feel free to submit a pull request. That said, if you’re ever stuck, we’re all here on @SendGrid, ready to help you out, so ask away.