If you are an aspiring Atlassian Marketplace vendor at the start of your journey, then you may be faced with the question of where to start. You may already have coding experience, which will go a long way. And you may have a brilliant idea for your first Marketplace App.
However, whilst you will have heard of of Atlassian Forge and Atlassian Connect, you may be unsure which is right for you.
Before I start and dive into the differences and where one may be a better choice than the other, it is important to note that, as an aspiring Marketplace vendor, you will need to have a good understanding of both Connect and Forge in order to make the right choice at the right time. At the very least you will need to know the "Art of the Possible", by which I mean having a fundamental understanding of what the two technologies can do for you and what their limitations are.
So, let's start with the bigger picture. The fundamental difference between Connect and Forge is whose responsibility it is to run the add-on in a production environment. A lot of the differences between the two platforms emerge as a result of that underlying premise.
With Atlassian Connect, it is the vendor's responsibility to operate a service that implements the features of the add-on. This means that you as the add-on developer not only have to write the code, you also need to ensure that once your add-on is published there is a service running at all times or your add-on will stop working for all of your customers.
Atlassian Forge, on the other hand, is fundamentally different. Atlassian look after your development, staging and production environments for your add-on. Your job as a vendor is to write the code, and Atlassian will look after the day-to-day operations. If the add-on service stops, Atlassian will restart it.
The fundamental idea of Connect is to completely detach the add-on from your Jira or Confluence instance. A connect add-on and the Atlassian instance it is installed in are very loosely coupled. As a result, Atlassian do not mind where in the world your add-on is running, what programming language(s) you have written it in, or how you deliver your services. All Jira needs is information on what your add-on can do and to respond to requests from Jira on the extension points that your add-on provides. If you really wanted to, you could even have an add-on powered by people rather than code. As long as the people respond back in the correct format, Jira and Confluence would not mind.
Connect add-ons give a vendor a lot of flexibility. If you already run a service and you would like to put extensions into Jira or Confluence to interact with your service, then Connect is probably the right choice for you at this point. You have more flexibility and it keeps your service and Jira very loosely coupled. For example, if you work for Dropbox and you want to integrate Dropbox with Jira, then a Connect add-on might be the right choice as Dropbox already exists as a service and has many and fairly large elements that do not depend on Jira.
If you do not currently have a service or if your app is an integral part of Jira/Confluence or if the service that you would like to integrate with is someone else's (i.e. not your own), then it would make more sense to look at Forge as your platform. Forge is growing every day and over the last year I cannot recall a month where there wasn't a significant feature release.
For example, one of the most recent features makes it easier for Forge apps to integrate with external services like Google etc by adding external authentication.
And this brings me to my final point. When it comes to whether to use Forge or Connect, if you still cannot make up your mind which is right for you, then just apply the following rule: if you can build your app with Forge, then you probably should.
Start learning about Forge: Jira Cloud App Development with Forge
Start learning about Connect: Jira Cloud App Development with Connect