Security practices in microservices development are the set of measures applied consistently across every service to protect communication, data, and access, since there's no single perimeter to defend.
Key Points: • Encrypt all service-to-service traffic with HTTPS/TLS to prevent eavesdropping, even on internal networks. • Apply the principle of least privilege — each service should hold only the permissions and data access it actually needs. • Keep dependencies and base container images patched regularly to close known vulnerabilities. • Use a centralized identity and access management (IAM) system, such as Keycloak or an OAuth2 provider, so authentication logic isn't duplicated and inconsistently implemented across services. • Log and audit access at each service so security incidents can be traced back to their source.
Example: A Java-based Order Service might use Spring Security with OAuth2 resource server support to validate JWT tokens issued by a central identity provider, rejecting any request that lacks a valid token before touching business logic.
Interview Tip: A concise interview answer is:
"I secure microservices in layers — HTTPS for all traffic, least-privilege access per service, a centralized IAM system like OAuth2 or Keycloak for consistent authentication, and regular patching of dependencies and container images. Because there's no single perimeter, every service has to enforce these practices independently."