A computer-implemented method of managing a succession of deployments of an application programming interface, API, server configuration, the method comprising: defining a first configuration of the API server, the first configuration embodied as a computer readable media encoding of a deployment package that encodes at least policy, filter, listener and external connection components of the defined first configuration together with environment settings particular to operation of the API server in a development environment deployment thereof; preparing a second configuration of the API server by decomposing the first configuration into portions that are environment specific and portions that are environment agnostic such that the first configuration is environmentalized when being promoted to a testing or production environment, so as to separate environment neutral aspects of policy, filter, listener and external connection components from environment specific aspects, the second configuration embodied as computer readable media encodings of (i) a policy package derived from the environment neutral aspects of the first configuration and (ii) a separable environment package particular to a testing environment deployment of the API server; preparing a third configuration of the API server, the third configuration embodied as computer readable media encodings of (i) the derived policy package and (ii) a separable environment package particular to a production environment deployment of the API server; and deploying at least one of the testing environment and the production environment, wherein the environment settings for the development environment deployment and the environment packages particular to the testing and production environment deployments of the API server specify, relative to their respective deployment environments, differing external resource locators, cryptographic certificates and user authentication parameters. defining a first configuration of the API server, the first configuration embodied as a computer readable media encoding of a deployment package that encodes at least policy, filter, listener and external connection components of the defined first configuration together with environment settings particular to operation of the API server in a development environment deployment thereof; preparing a second configuration of the API server by decomposing the first configuration into portions that are environment specific and portions that are environment agnostic such that the first configuration is environmentalized when being promoted to a testing or production environment, so as to separate environment neutral aspects of policy, filter, listener and external connection components from environment specific aspects, the second configuration embodied as computer readable media encodings of (i) a policy package derived from the environment neutral aspects of the first configuration and (ii) a separable environment package particular to a testing environment deployment of the API server; preparing a third configuration of the API server, the third configuration embodied as computer readable media encodings of (i) the derived policy package and (ii) a separable environment package particular to a production environment deployment of the API server; and deploying at least one of the testing environment and the production environment, wherein the environment settings for the development environment deployment and the environment packages particular to the testing and production environment deployments of the API server specify, relative to their respective deployment environments, differing external resource locators, cryptographic certificates and user authentication parameters.