API migration refers to the process of moving an application programming interface (API) from one environment to another. This may involve migrating an API to a new platform, updating an API to a new version, or consolidating multiple APIs into a single platform. The goal of API migration is to improve the overall quality, performance, and efficiency of an API while minimizing disruption to existing users and systems.
Why migrate an API?
There are several common reasons organizations choose to migrate their APIs:
- To move to a newer, supported platform or framework – For example, migrating from legacy platforms to more modern architectures like cloud-native microservices.
- To consolidate multiple APIs into a unified platform – Consolidating APIs improves consistency across products/services and makes APIs easier to maintain and secure.
- To upgrade to a new version of an API – Adding new features, improving performance, enhancing security, etc.
- To improve scalability and reliability as usage grows – Migrating to auto-scaling cloud platforms.
- To adopt new standards or protocols – Adopting new API styles like GraphQL or new protocols like HTTP/2.
Overall, API migration is usually done to improve the developer/user experience, lower costs, reduce maintenance burden, or enable adoption of new technologies.
Challenges with API migration
Migrating APIs introduces some key challenges including:
- Compatibility – The new API needs to work for existing clients/integrations without requiring them to change.
- Testing – Rigorous testing is required to ensure the new API functions properly beforeswitching over.
- Coordination – Migration requires coordination across potentially many internal teams and external developers/partners.
- Downtime – Strategies are needed to minimize downtime and errors during the transition period.
- Client adoption – Users of the old API need to be incentivized and supported in switching to the new one.
API migrations can be complex endeavors, especially for large organizations with many internal and external dependencies. Careful planning is required for a successful transition.
API migration process
A best practice API migration process generally involves the following key steps:
- Audit – Understand how the existing API is used including usage statistics, peak traffic times, client dependencies, etc.
- Plan – Develop a detailed migration plan and timeline. Consider compatibility, testing, client coordination, rollback, etc.
- Build – Develop and test the new API platform. Use good API design practices.
- Test – Thoroughly test the new API and validate it works for existing use cases.
- Release – Make the new API available to clients, potentially keeping old API online temporarily.
- Migrate – Gradually shift client traffic from old to new API. Provide docs, SDKs, support, etc.
- Decommission – Once migration is complete, retire the old API.
- Monitor – Closely track usage, errors, performance of new API post-migration.
This process ensures a smooth transition with minimal disruption to API consumers. The specific technical steps will vary depending on the platforms and architectures involved.
API migration strategies
There are a few common techniques used when executing an API migration:
Parallel deployment
- Run the old and new APIs simultaneously
- Gradually shift traffic from old to new
- Allows testing and a graceful transition
- Requires temporarily operating two platforms
Gateway redirection
- Use an API gateway to receive all requests
- Gateway redirects requests to old or new API
- Allows redirecting traffic gradually
- Transparent to clients
Endpoint redirection
- Individual endpoints can redirect clients to new location
- Useful when migrating endpoints incrementally
- Clients must handle redirects
Custom header
- Add custom request header to indicate API version
- Backend routes request based on header value
- Allows client to explicitly opt-in to new API
The best strategy depends on the specific constraints and complexity of the migration project.
Best practices for API migration
Some best practices to follow for a smooth API migration include:
- Maintain compatibility with existing clients as much as possible
- Use semantic versioning and deprecation notices before removing functionality
- Provide comprehensive documentation and examples for the new API
- Develop migration tools and scripts for major clients where feasible
- Offer developer support and training materials surrounding migration
- Implement robust monitoring and alerting to detect issues
- Have a rollback plan in case migration causes major problems
- Gradually redirect clients to new API rather than a hard cutover
- Communicate timelines and changes early and often
With careful planning and execution, API migrations can be completed smoothly and transparently for clients. But the process needs to be taken seriously to avoid disruptions that impact customers and partners integrating with the API.
API migration tools
There are a variety of open source and commercial tools available to assist with different aspects of API migration:
| Tool | Description |
|---|---|
| Postman | Popular tool for API development, testing, documentation. Useful for testing API migrations. |
| Amazon API Gateway | Managed API gateway service. Provides redirection and traffic shifting capabilities. |
| Kong | Open source API gateway and management layer built on Nginx. |
| Tyk | Open source API gateway for managing, securing and routing APIs. |
| Stoplight | Collaborative design, documentation and testing platform for APIs. |
| Swagger | Tools for designing, documenting and consuming REST APIs. |
These tools and cloud platforms provide capabilities like API designers, gateways, testing frameworks, and documentation that are useful for migrating APIs. They help streamline various aspects of migration from planning through client integration.
Migrating from REST to GraphQL
One API migration scenario is transitioning from a REST API to GraphQL. Some key considerations for this migration include:
- Build a GraphQL schema and object types to match existing REST endpoints
- Expose GraphQL API alongside existing REST API
- Use GraphQL wrappers to call REST endpoints during transition
- Progressively move resolver logic from REST to GraphQL
- Provide tools to migrate client requests from REST to GraphQL
- Set deprecation notices for removed REST endpoints
- Monitor performance and optimize GraphQL queries
- Eventually retire the old REST API
GraphQL can provide significant developer experience improvements over traditional REST. But clients need ample support to safely transition over without disruption.
Migrating cloud APIs
Migrating APIs hosted in the cloud involves some unique considerations:
- Use cloud native capabilities for blue-green and canary deployments
- Leverage auto-scaling and load balancing features
- Implement robust monitoring and logging
- Manage DNS and traffic routing through cloud
- Focus on stateless architecture
- Utilize infrastructure-as-code and automation
- Plan for potential cloud provider lock-in
Cloud platforms provide many tools to support reliable API migrations. But portability remains an important concern when migrating cloud-native APIs.
Common migration risks
Some key risks to manage with any API migration include:
- Functionality regressions in the new API
- Integration failures for existing clients
- Unexpected performance degradations
- Security vulnerabilities introduced
- Partial or failed migrations leaving systems unstable
- Cost overruns and timeline delays
- Business disruption if migration problems are severe
Proper testing, rollback plans, client support and communication are critical to avoiding these pitfalls.
API versioning strategies
Effective API versioning strategies are important for smooth migrations. Some options include:
- URI versioning – Include version in URL like /v1/users
- Request parameter – Pass API version as a parameter
- Custom header – Use custom header to specify version
- Accept header – Use HTTP Accept header to indicate version
URI versioning is most common. But multiple strategies used together can provide flexibility during a migration.
Conclusion
To summarize, API migration involves moving an API to a new environment or version while minimizing disruption to clients. A successful migration requires planning, strong testing, and coordination across teams and clients. Various techniques and tools can assist with migrating APIs and versioning allows a gradual transition. With a thoughtful approach, API migrations can improve capabilities and deliver significant long-term benefits while avoiding risks.