Clever Functions (FaaS)
Based on the WebAssembly (Wasm) standard and on WSR — Wasm Svm Runtime, an internal technology developed over several years, it provides very fast, hardware-adjacent execution and supports a wide range of programming languages.
Clever Functions is currently available in private alpha. You can request early access.
Clever Functions: Fast execution. Strong isolation. Serverless model.
Clever Functions is built on an event-driven architecture: functions run when a specific event occurs, such as an HTTP request, a database update or a message in a queue.
Clever Cloud manages all resources automatically. You deploy your functions; the platform handles the rest.
Technical operation
To achieve fast and isolated execution, Clever Cloud built its own low-level virtualisation layer. It activates lightweight environments as close as possible to the CPU while retaining the strong isolation already present throughout the platform.
The execution engine relies on two components:
- Wasm and Wasm System Interface (WASI): an open standard compatible with many languages (Go, Rust, Zig, C, JavaScript, AssemblyScript…).
- WSR (Wasm Svm Runtime): designed to provide fast execution, multi-language support and a simple operating model.
This architecture avoids dependence on a single runtime and supports adoption across heterogeneous engineering teams.
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01
01 Very fast execution
WSR starts functions in a very short time: around a millisecond on cold start and down to the nanosecond on warm start. Lightweight virtualisation, activated close to the CPU, reduces latency and limits the cost of the first execution of a function.
0202 Open, multi-language WASM standard
Using Wasm/WASI ensures broad language compatibility without relying on a single ecosystem. Rust, Go, Zig, C, JavaScript and AssemblyScript can be compiled to Wasm and executed directly.
0303 Strong isolation by design
Each function runs in a dedicated environment, encapsulated within a KVM enclave and isolated from the rest of the platform.
This approach reflects Clever Cloud’s philosophy: maintaining strict separation between executions to reinforce security and stability.0404 Event-driven triggers
Functions react to clear signals:
- HTTP requests
- database modifications
- messages in queues
0505 Usage-based pricing
You only pay for actual execution time. The FaaS model avoids maintaining idle resources and adapts well to variable workloads.
Use cases:
- Application automation – Trigger one-off or recurring actions: data transformations, clean-up tasks, business rule checks.
- Webhooks and external integrations – Process HTTP requests directly without a dedicated server.
- Event-oriented pipelines – Process data flows or workflows triggered by queue messages.
- Isolated microservices – Implement autonomous components without managing continuous instances.
Why use Clever Functions?
Simple architecture
No instances to maintain. One function = minimal deployment.
Integrated into the Clever Cloud ecosystem
Clever Functions is designed to fit naturally into the platform’s operating model: managed deployment, centralised supervision and a consistent experience across Clever Cloud products.
Technological openness
WASM/WASI enables the use of multiple languages within the same project.
European-operated infrastructure
Clever Functions runs on Clever Cloud’s European-operated infrastructure, compliant with ISO 9001, ISO 27001:2022 and HDS security standards.
Early access
The service is available in private alpha. Contact the team to evaluate the solution.
Clever Functions provides fast, isolated, event-driven execution based on a modern Wasm runtime designed for simplicity. This model reduces operational complexity and integrates naturally into modular or event-oriented architectures.
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