Question 1

What are the core differences between internal and external API design?

Accepted Answer

Internal APIs prioritize developer efficiency and system integration, while external APIs focus on security, developer experience, and ecosystem expansion. Internal APIs often have relaxed authentication, whereas external APIs require rigorous security protocols and comprehensive documentation.

Question 2

Why should authentication approaches differ between internal and external APIs?

Accepted Answer

Internal APIs can use simpler authentication like API keys or IP whitelisting since they operate within trusted networks. External APIs require OAuth 2.0, JWT tokens, or API gateways to prevent unauthorized access and protect sensitive data from public exposure.

Question 3

How does versioning strategy differ for internal vs external APIs?

Accepted Answer

Internal APIs can use aggressive versioning with frequent breaking changes since consumers are internal teams. External APIs require strict versioning policies, long-term support for deprecated versions, and backward compatibility to maintain partner integrations and prevent ecosystem disruption.

Question 4

What documentation standards apply to external APIs that aren't critical for internal APIs?

Accepted Answer

External APIs demand interactive documentation (Swagger/OpenAPI), SDKs in multiple languages, detailed error code references, and onboarding guides. Internal APIs typically require minimal documentation since knowledge sharing happens through internal channels and team collaboration.

Question 5

Why is rate limiting more crucial for external APIs?

Accepted Answer

External APIs need strict rate limits to prevent abuse, ensure fair usage across partners, and protect backend systems from DDoS attacks. Internal APIs may implement softer throttling primarily for resource optimization rather than security enforcement.

Question 6

How should error handling differ between API types?

Accepted Answer

Internal APIs can return technical error details for debugging efficiency. External APIs must provide user-friendly, sanitized error messages without exposing system internals, along with standardized HTTP status codes and troubleshooting guides.

Question 7

What SLA requirements distinguish external APIs?

Accepted Answer

External APIs require formal SLAs with guaranteed uptime (99.95%+), performance benchmarks, and financial penalties for violations. Internal APIs typically have informal agreements based on team expectations and operational priorities.

Question 8

Why do external APIs need more sophisticated monitoring?

Accepted Answer

External APIs require real-time analytics on usage patterns, geography-based performance tracking, threat detection systems, and partner-specific metrics to maintain service quality, identify business opportunities, and prevent security breaches.

Tag: Internal apps

9 aspects to consider while developing APIs for Own platform Vs Data service to other platforms

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