The all-pervading digitalization of business processes has brought API (Application Programming Interface) integration companies to the forefront. These are the entities that facilitate the seamless communication between disparate software systems. Harnessing the power of APIs allows businesses to enhance their operational capabilities, improve customer experiences, and drive innovation. However, with a plethora of API integration companies proliferating the market, choosing the right partner can seem like a daunting task. Prior to making a decision, it is incumbent upon businesses to ask a few critical questions to the prospective integration company.

First off, it is imperative to delve into the level of expertise the company possesses in API integration. Have they accumulated years of experience or are they recent entrants? A seasoned company is likely to be well-versed with the intricacies of API integration, and can, therefore, provide comprehensive solutions that are tailored to a business's specific requirements.

Further, in an era where the API economy is burgeoning, businesses must inquire about the range of APIs the integration company can handle. Do they have experience with RESTful, SOAP, XML-RPC, or JSON-RPC APIs? Depending upon the business's existing systems and future needs, it might be more beneficial to opt for a company that can work across a wide array of API protocols.

The performance and reliability of APIs are paramount for businesses seeking to avoid disruptions in their operations. Therefore, a key question to ask would be: How does the API integration company ensure optimal performance and reliability? This could be through various means including load testing, stringent quality control checks, or implementing robust error reporting and monitoring systems.

In the current business landscape where data is the new oil, it is crucial to assess the security measures employed by the API integration company. How do they ensure the secure transmission of data? Do they comply with relevant industry standards and regulations? A company that prioritizes security is of immense value in today's digital world prone to data breaches and cyberattacks.

Another important consideration is the scalability factor. As businesses grow and evolve, their API integration needs may also change. Hence, it is prudent to ask: How scalable are the integration company's solutions? Can they cater to a business's growing needs seamlessly without necessitating major overhauls?

The support provision is another aspect businesses should not overlook. Post-integration support services can significantly help in troubleshooting and maintaining the integrated systems. Thus, inquire about the nature and extent of the support services offered by the company.

Investigating the company's pricing model should also be factored in to ensure that it aligns with the business's financial plans. Is it a one-time cost or a recurring subscription fee? Are there any hidden costs that may arise later on?

Lastly, it would be prudent to ask for references or case studies that demonstrate the company's work. This can provide insights into the complexity of projects the company has handled successfully, and their ability to deliver results.

In essence, the choice of an API integration company significantly impacts a business's digital transformation journey. Therefore, it becomes essential for businesses to conduct thorough due diligence by asking these fundamental questions. By doing so, they can align their choice with their strategic objectives, thereby maximizing the value derived from API integration.