APIs (Application Programming Interface) have become integral to the development landscape, with between 26 and 50 APIs powering an average application according to Postman’s 2024 State of the API report. However, a clear shift to an API-first approach over the last few years has been accelerating production times, enhancing collaboration, speeding up delivery, and ensuring that APIs remain protected and optimized for future needs. According to the report, 74% of respondents adopted an API-first approach this year, up from 66% in the previous year. This article will focus on the shift from APIs to an API-first approach in the software industry and the importance of that change.
What is an API and what was the traditional approach to developing it?
An API is a collection of rules and protocols that enable software applications to communicate, exchange data, and share functionalities. It operates as a bridge between different software components and enables them to interact smoothly and seamlessly. The traditional approach to API development, often called “code-first,” involved prioritizing coding, defining requirements, testing, documenting, and deploying, leaving API design as an additional task along the way.
What is an API-first development approach?
In an API-first development approach, an API is a top priority – designed and developed before any other part of the application. Applying such a practice leads to better integration, heightens efficiency, and eliminates customization issues. In an API-first development approach, an API is considered a standalone product with its own software development life cycle, which enables effortless code reuse, potential for scaling, and readiness for future projects. API-first development also encompasses rigorous testing and validation to ensure the solution meets all compatibility and security requirements.
The key principles of API design
What are the best practices and principles for universal API design that software developers should follow? By adhering to the following standards, developers can create APIs that are not only functional but also intuitive and efficient for end users:
- Simplicity – designing an intuitive, easy to understand and use software interface for developers,
- Consistency – maintaining consistency in naming convention, structure, behavior, and using common standards (i.e. REST API),
- API versioning – introducing API versioning to allow for complete backward compatibility whenever required,
- Security – protecting sensitive information, adhering to high-security standards, using techniques like OAuth 2.0, token-based authentication and data encryption,
- Performance – handling large-scale usage, taking advantage of techniques such as caching, pagination and rate limit when needed,
- Scalability – developing an API that’s able to accept higher traffic, new integrations or additional endpoints without major redesign,
- Error handling – implementing a clear and consistent error messages system and presenting standardized status codes,
- Documentation – fostering up-to-date documentation, introducing a suite of tools like Swagger or publicly available OpenAPI standards.
An API-first approach versus a code-first approach – what are the differences?
There are several key differences between an API-first approach and a code-first approach. The table below highlights them. Ultimately, adopting the API-first approach requires the team to shift its mindset and workflow, which significantly impacts the software development life cycle.
| Aspect | API-first approach | Code-first approach |
| Definition | Designed and planned before any code is written | Created after a feature is developed |
| Priority | API treated as a core product | API is a secondary priority, often developed after the core functionality |
| Workflow | Specification, mockup and API contracts created upfront | Evolves as development progresses |
| Collaboration | Promotes collaboration among frontend developers, backend developers, and architects early on | Collaboration between various developers occurs later during the integration phase |
| Documentation | A part of the design process, often created automatically | Added after the development process, sometimes manually |
| Testing | Allows early testing through mockups | Testing occurs after the designed functionalities are ready |
| Consistency | Enforcing standards across API from the beginning | Consistency may warry depending on devewlopers team management |
| Flexibility | Encourages modularity and adaptability | Changes often require significant rework due to backend coupling |
| Integration speed | Faster integration as API is ready even before backend is finished | Slower integration as API is available after backend development |
| Scalability | Designed with scalability and future proofing | Might require redesign to scale or introduce changes |
| Error handling | Error handling is part of early-stage planning | Error handling added later, often inconstantly |
| Consumer-centricity | Focused on needs of API consumers | Focused on backend functionalities |
The benefits of an API-first approach
Choosing an API-first approach comes with several advantages for the developers and businesses that decide to pursue this practice. What are the most noteworthy ones?
- Faster development – Frontend and back-end teams working together from the first kick-off meeting allows for more synchronized and efficient custom software development.
- Less debugging – By adopting an API-centric approach, software teams collaborate to achieve a shared goal, and with automated testing, early identification and bug resolution are more manageable.
- Focus on innovation – A clear vision delivered with an API-first approach frees us developers, who can spend more time designing innovative features. It gives space for lean solutions, thus accelerating time-to-market.
- Enhanced productivity – API documentation and API contracts allow for more productive team cooperation while modularity and adaptability streamline the development process.
- Empowerment of non-developers – The created documentation and broad third-party integrations facilitate a more simplified integration. Introducing Low-Code/No-Code (LCNC) allows non-developers to integrate designed solutions into their products.
- Faster issue resolution – Potential issues can be isolated faster than with a code-first approach and resolving them is a more streamlined process thanks to the potential of rapid iterations and quick deployments.
- Simplified compliance and governance – A centralized API layer can help enforce security and compliance standards by monitoring and ensuring adherence to regulations.
- Competitive advantage – An API-focused approach facilitates more robust ecosystem development, enabling third-party developers to build on your platform, encouraging innovation and fostering a community.
API-first approach use cases
It’s time for some practical examples. Most enterprise-level organizations maintain over 1,000 APIs in their landscape, most of which are intended for internal use, as reported in Anatomy of an API (2024 Edition). There’s plenty to choose from, but let’s focus on five interesting cases.
Booking – The renowned travel technology company uses an API-first approach to give external companies and partners access to its database of accommodations and services.
PayPal – This leading eCommerce platform has successfully reduced the time to first call (TTFC) – the period between a developer accessing documentation or signing up for an API key and making their first successful API call – to just one minute. There are already over 30,000 forks of PayPal APIs, demonstrating that an API-first approach benefits both partners and businesses.
Spotify – By employing an API-first approach, the music platform enables developers and partners to access its music resources and create applications across various platforms. This practice helps Spotify maintain consistency across mobile, web, and external service integrations.
Stripe – API-first allows Stripe, a financial company that provides an API for online payment processing, to provide flexible and scalable payment solutions that can be quickly deployed in various applications and services.
Zalando – The well-known German online trader utilizes an API-first approach to effortlessly scale its services, integrate with external applications, and respond quickly to market changes.
The future of an API-first approach
APIs and an API-first approach are here to stay, but how will they influence the development community and various tech sectors? Here are the most crucial domains it will excel in.
Artificial intelligence (AI) and machine learning (ML) support
API-first architecture will facilitate custom AI and ML integrations, so developers and users can leverage the latest language models and machine learning tools. AI-powered solutions are increasingly automating API creation, significantly reducing development time. According to Anatomy of an API (2024 Edition), the number of AI-related APIs in 2024 increased by 807% compared to the previous year, while the average growth across all other sectors and industries was 10%.
API demand in the IoT world
With the increasing demand for well-designed device APIs, the importance of device interoperability will only rise. This development enables seamless communication and data exchanges between various devices and systems, regardless of their manufacturer or platform. An API-first approach in IoT-related industries will also facilitate the rapid processing and analysis of device-generated data.
API as a product
Companies will monetize their APIs, offering API-as-a-service products. Well-documented, reliable, and easy-to-use APIs can be treated as commercial products and create new revenue streams for companies willing to share their API platforms.
LCNC platforms and APIs
APIs will increasingly be integrated into low-code and no-code and applications, accelerating development time and reducing costs. By making software development more accessible to a wider audience, an API-first approach will empower non-technical users to play a part in the tech community.
The modern world runs on APIs
The average API in 2024 had 42 endpoints, representing a substantial increase since last year when the average was just 22 endpoints. By 2025, APIs will become increasingly complex and essential for businesses, requiring companies to adopt an API-first approach. Adopting an API-first approach can help your company prioritize the design and development of APIs, leading to more efficient and scalable software systems. Furthermore, it promotes better collaboration among teams, reduces development time and costs, and facilitates faster innovation and adaptation to changing market demands.
If you want to explore an API-first approach, update your existing APIs or learn how APIs can transform your business, contact our experts using this form.
About the authorMateusz Szopa
Senior Software Developer
With almost 8 years of experience in software development, Mateusz specializes in building robust, scalable solutions using .NET technologies. As a Tech Lead, he guides teams in delivering high-quality software while fostering collaboration and innovation. A strong advocate of Domain-Driven Design (DDD), he is passionate about creating software that aligns closely with business needs. He is dedicated to continuous learning and refining best practices in software development.
