What questions should I ask before buying an ESB?

There are two kinds of integration piece ESB & EAI. If your requirement is for basic integration(Web services) then ESB would be helpful. If you have traditional or legacy systems that communicate with legacy protocols and message formats then ESB would be a bit harder to use as you need to develop adapters for those legacy systems by your own. On the other hand EAI is an extension to ESB by vendors and it offers ready made tools and adapters which can ease your integration. But cost is involved there.

ESBs are now about 10+ years old. Evaluation practices are now well established as follows (key ones):

1. For low cost and pay per use look for iPaaS options rather than on-promise installs. You have the option to move over to something better later.

2. Look for skilled resources at your end. Fancy high end ESB could cost you for usage and also resources in demand.

3. What are the integration needs of your org? Are your apps legacy, what are their integration capabilities? This will highlight the need for adapters (tight-coupling), or loose coupled integrations like HTTPS or JMS/MQ, etc.

5. Look for ease of use for developers and monitoring capabilities of ESB.

6. Always carryout end to end POC before making any commitment to any vendor. Have this done with specific use cases or your org.

For purchasing the ESB, you should ask the few questions below:
1. It should be highly scalable, re-usability and low cost.
2. The related company should provide good support in case of environmental issues.
3. Security should be good in case of inbound and outbound messages.
4. Should be supported by a wide range of protocols and adapters.
5. With the wide adoption of cloud and SaaS applications, integration needs to support on-premise, hybrid, and cloud/SaaS applications.

1. What kind of integration do you need? Does the supplier understand your problem domain? Do you focus on flexibility, on speed of integrating, etc?
2. Are the so called adaptors there which you need? Also the protocols supported you need?
3. How is security enabled?
4. Does it run on own servers, or in cloud?
5. How complex is the development cycle, and the management of versions of processes and interfaces? Error management?
6. Pricing including stages you may need, amount of licences you need for larger Environments,... till long term costs
7. What kind of infrastructure is needed?
8. Is federation of ESBs important for you, if so, how is it supported?
9. Who will do the implementation and the operative management of the ESB?
10. Performance?
11. Config Management?
12. Vendor support - how fast, how expensive?

Check out www.Chakray.com/

The main question about an ESB is to understand if you need an ESB to implement links between partners together in a kind of workflow or if you want to link the partner in the same business process.

You have to understand that the ESB market can be shared in two parts:

1- The workflow managers (MULE, WSO2, Dell Boomi...) link efficiently one partner (ex: applications, data containers, resources, external services) but offer a few possibilities to involve theses partner in complex and Sophisticated business processes. 

2- On the other side, the Orchestrators (Oracle, Tibco, OpenESB) implement complex processes that required overworks when you just need to connect a Database with a microservices.

The main difficulty in that choice is that after the first project implementations it often come more complex projects that require complex process implementations and changing for another product is often impossible only after a few months.

We have to evaluate what is your real integration needs and the Complexity of your future projects.

The other criteria are less relevant since each large editor provides a large scope of adapters, good scalability and certainly good support. 

Check out:

www.tibco.com/
community.tibco.com/