Decentralized services and applications provide a multitude of advantages for their users, such as improved privacy, control, and independence from third parties. Anyhow, decentralization comes at the cost of certain disadvantages, such as increased application complexity or communication overhead. This aggravates the development and deployment of decentralized services and applications. In this paper we present Blade, a software platform that aims to ease the effort of development, deployment, and administration of decentralized services by implementing reusable solutions for recurring challenges developers are facing when designing decentralized service architectures. This includes functionality for e.g. identity management, access control, request handling, verification of authenticity and integrity, discovery, or routing. Blade implements all this functionality in a Blade server instance, which can be deployed on a lightweight device, such as a NAS, Raspberry Pi, or router at home. This allows users without expert knowledge to run a Blade instance with already existing hardware with little overhead. Blade supports polyglot Blade modules that implement extended functionality, such as interfaces, frontends, and business logic of decentralized applications, e.g. a decentralized instant messaging service or an online social network. Based on the Oracle GraalVM, Blade modules can be implemented in a variety of programming languages and utilize the functionality provided by the Blade server instance. Blade modules are published in a Ethereum-based decentralized marketplace from where they can be installed directly via the Blade instances...