2021 was undoubtedly a big year for APIs. Amid rapid digitalization, APIs propelled many areas of the digital economy, powering many of the apps we use all the time. They can enable agile eCommerce, mainframe modernization, make DevOps tools more programmable, and bring flexibility to many other environments. APIs are becoming ubiquitous, and 68% of developers expect their usage to rise in 2021.

With all this excitement in the market, it’s good to keep a solid footing of the attitudes and experiences of actual developers implementing the technology. That’s where RapidAPI’s State of APIs Developer Survey 2021 Report comes in. The survey questioned over 2,200 professionals on their use of APIs, including responses from full-stack, backend, frontend, and mobile developers.

The findings show an increase in API reliance across the board, with a particular uptick in partner-facing API development. As the API-as-as-Product pundits will tell you, no longer are APIs internal-only tools — they are transforming into valuable commodities.

Below, I’ll cover the key takeaways from the report. I also synced with Iddo Gino, Founder and CEO, RapidAPI, for an inside scoop.

Rising API Reliance

More developers are beginning to rely on APIs in their daily work. This year, an extra 26% of developers expect to rely on APIs in the coming year. In total, 90.5% of developers expect their API usage to remain about the same or increase.

Across the board, APIs are becoming more of a foundational toolset for many sectors, including financial services, telecommunications, healthcare, and technology companies. Out of these categories, healthcare anticipates the biggest increase in API usage — 71% of respondents working in healthcare expect to rely more on APIs in 2022.

75% of developers prioritize or plan to prioritize participating in the API economy. Financial services are significantly more likely to rely on APIs, underlying the importance of APIs in issuing online payments and enabling open banking.

An Increase in Partner and Public APIs

Developers are not only consuming APIs, but many are building their own. Though 74.4% of APIs are built for internal use, the study found an uptick in partner and third-party API development. Compared to 2020, 27.7% more developers are creating partner-facing APIs. The amount of third-party-facing APIs also rose by 4.3%.

According to Gino, there are three main drivers behind this momentum: shifting consumer expectations, the realization of assets, and better technology to enable APIs. “Increasingly, consumers expect different applications and software to just work together,” he explains. “This necessitates more API integrations — and more companies to expose public APIs powering them.”

The increase in external API models occurs amid a rise in VC funding for API-centric companies and the commercial viability of public API-as-a-Product initiatives.

These trends indicate the latent business potential in exposing internal tools. “Executives are becoming better informed and realize how much they can gain by exposing certain data and functionality they already have to the world as public APIs,” says Gino.

As a result, data shows an increase in API monetization. In 2021, 40.5% of developers say their organization has monetized an API, an increase of 35.4% from 2020.

Shifts in Developer Tooling

When it comes to API style, no two APIs are identical. Though most web APIs are RESTful and serve up JSON, many different API styles and tools are used in development, including webhooks, web sockets, SOAP, and GraphQL.

59.7% of developers use REST for their APIs in production. On the other hand, 20.5% of APIs adopt SOAP, a slightly older, more structured design pattern that uses XML. GraphQL adoption has seen much excitement in recent years, but it still experiences relatively small adoption — 14.7% utilize it in production.

Different use cases beget different API styles. “In the past companies looked to have a single API format,” explains Gino. “The future of API formats is very heterogeneous — companies realize the value of having multiple API types best suited for specific use cases.”

Another relatively new tool for documenting APIs is AsyncAPI, an open specification format similar to OpenAPI Specification but intended to describe asynchronous services. In 2021, 21.8% of developers use AsyncAPI in production.

Developer language preferences are slowly evolving as well. The report found that JavaScript remains a top language of choice — 72% of developers use JavaScript. The study also found a rise in Python and TypeScript interest, while Java, PHP, C#, and .NET declined.

Impending Problems for APIs

Over 50% of large companies have 100 internal APIs or more. And maintaining this expanding library of APIs can get cumbersome — especially as data privacy and security concerns are on the rise. As a result, API-specific testing is often utilized to spot bugs early on and maintain reliable services. 41.9% of developers use tools to support their API testing. The most common API test types include functional testing, integration testing, and acceptance testing.

Another potential concern is the drought of engineers amid the ‘Great Resignation.’ The report found 54% of developers have considered leaving their current position. Top reasons for leaving include a higher compensation, interest in a specific technology, product, or company, and a more flexible work environment.

“Every company is quickly realizing that software development plays a huge role in their future and everyone is rushing to hire developers,” explains Gino. “The developers have a free choice of where they want to work and what they want to work on – fueling a massive transition.”

Companies that haven’t invested in empowering developers with innovative technologies could lag in adopting and maintaining APIs — inhibiting them from taking full advantage of the API economy.

Analyzing Developer Attitudes Toward APIs

During efforts to enact digital transformation, APIs play an important role across sectors. And, studies prove that API reliance is increasing throughout most companies.

What I find most interesting is the shift toward more companies planning to build and offer APIs themselves. This will likely move more developers toward gateways and platforms that enable them to easily expose, monetize, secure, and manage their web services.

The third annual 2021 RapidAPI State of APIs survey collected over 2200 responses from 130 countries. They surveyed respondents from their API Hub, a marketplace of over 35,000 APIs. The survey also sourced answers from other developer events and forums like APIWorld/APIDays.