I solved with this `application.yml`:
``` spring: cloud: gateway: routes: - id: openapi uri: http://localhost:${server.port} predicates: - Path=/v3/api-docs/** filters: - RewritePath=/v3/api-docs/(?<path>.*), /$\{path}/v3/api-docs - id: characters-service uri: lb://characters-service predicates: - Path=/characters-service/** filters: - RewritePath=/characters-service/(?<path>.*), /$\{path}

springdoc: enable-native-support: true api-docs: groups: enabled: true enabled: true group-configs: - group: api-gateway packages-to-scan: - dev.kambei.apigateway display-name: API Gateway - group: characters-service paths-to-match: - /characters-service/** display-name: Characters Service swagger-ui: config-url: /v3/api-docs/swagger-config url: /v3/api-docs urls: - url: /v3/api-docs name: API Gateway - url: /characters-service/v3/api-docs name: Characters Service ```

I solved with this `application.yml`:
``` spring: cloud: gateway: routes: - id: openapi uri: http://localhost:${server.port} predicates: - Path=/v3/api-docs/** filters: - RewritePath=/v3/api-docs/(?<path>.*), /$\{path}/v3/api-docs - id: characters-service uri: lb://characters-service predicates: - Path=/characters-service/** filters: - RewritePath=/characters-service/(?<path>.*), /$\{path}

springdoc: enable-native-support: true api-docs: groups: enabled: true enabled: true group-configs: - group: api-gateway packages-to-scan: - dev.kambei.apigateway display-name: API Gateway - group: characters-service paths-to-match: - /characters-service/** display-name: Characters Service swagger-ui: config-url: /v3/api-docs/swagger-config url: /v3/api-docs urls: - url: /v3/api-docs name: API Gateway - url: /characters-service/v3/api-docs name: Characters Service ```