Welcome to Fascia
Fascia is a spec-driven backend platform that lets you design, govern, and execute production backend systems without writing traditional server code. You define your business logic through structured specifications — Entities, Tools, Policies — and Fascia's deterministic engine handles execution, transactions, and safety enforcement automatically.
What makes Fascia unique is its separation of design and execution. During the design phase, AI assistants help you define specs, detect unsafe patterns, and generate test cases. At runtime, there is no AI involved whatsoever. A deterministic Go-based executor runs your flow graphs inside your own cloud infrastructure, following an immutable 9-step Execution Contract for every operation.
Fascia deploys entirely within your own GCP project. Your data, your infrastructure, your control. Fascia's control plane only stores specs and metadata — never your business data.
Key Principles
- Spec-Driven -- All runtime behavior is derived from structured specifications. Entities, Tools, and Policies are the source of truth.
- No LLM at Runtime -- AI is used only during the design phase for spec authoring and safety analysis. The runtime executor is purely deterministic with zero AI calls.
- Deterministic Execution -- Every Tool invocation follows the same 9-step Execution Contract. Behavior is predictable, transactional, and auditable.
- Policy-First Safety -- Unsafe operations are caught and blocked at design time, not runtime. A Risk Engine classifies every Tool before deployment.
- BYOC (Bring Your Own Cloud) -- All runtime infrastructure lives in the customer's own GCP project. Fascia never stores or processes customer data.