A simulation layer for live sites
Stage sits between your frontend and downstream APIs. It intercepts responses and applies scoped overrides — letting teams test scenarios without touching production data.
Think: Figma for live websites
Just like Figma lets you edit designs without touching code, Stage lets you edit how your site behaves without touching the data behind it.
What makes Stage different
Read-Only to Your Systems
Stage never writes to your database, CMS, or catalog. It only transforms what the frontend sees — your source of truth stays untouched.
Zero persistence by default
Simulations are ephemeral. When you remove the scenario, reality returns.
Not a CMS. Not Feature Flags.
Stage doesn't replace your existing tools — it works with them. Override responses from any API: CMS, catalog, search, third-party services.
How the simulation works
Your app calls Stage instead of the API directly. Stage fetches real data, applies your overrides, and returns the simulated response.
Your app initiates request
Call the Stage Gateway with your API key and dependency slug
https://gateway.usestage.dev/gw/YOUR_KEY/cms/productsGateway authenticates
Environment API key validates your request and loads configuration
Scenario detection
Checks for active scenario via X-Scenario header or query parameter
Forward to upstream
Gateway proxies request to the real third-party dependency
Receive response
Upstream dependency returns its response to the Gateway
Apply transformations
If scenario active, matching rules mutate the response in priority order
Return to your app
Final (possibly transformed) response is sent back to your application
Organize simulations with Scenarios
Group related overrides together. Activate a scenario to see a complete alternate reality.
Scenarios
A Scenario is a named configuration context that groups related transformation rules.
Rules
Each Rule specifies match criteria and transformation actions.
Priority-based execution: Rules execute in order, giving you full control over the transformation pipeline.
Security & Isolation
Enterprise-grade security with strong tenant isolation
Encrypted Credentials
Auth credentials encrypted at rest with KMS
Tenant Isolation
Every request scoped to environment API key
No Secret Logging
Sensitive headers never logged or persisted
Header Allowlists
Control which headers forward to upstream