Catch Behavioral Changes Before Production.
Compare dependency behavior across versions. Investigate differences with reproducible evidence before bumping versions in production.
Twin Sandbox Isolation
Parallel Node.js child processes for zod@3.23.8 vs zod@4.6.7 with 5s watchdog timers.
Deterministic AST Comparator
Zero-AI mathematical comparison categorizes outputs into 4 deterministic tiers before any model inference.
NVIDIA Nemotron on Nebius
Synthesizes observable AST diffs into root causes, blast radius estimates, and before/after migration code.
Interactive 3D Execution Topology
Controlled differential testing from input dispatch to evidence-grounded model synthesis.
Compares return data, error arrays, and property removals mathematically without AI guessing.
Deep structural AST equality checks and property-retention assertions.
In-memory deterministic algorithm; zero AI hallucination.
How to Use ShadowBump AI
Follow these simple steps to analyze, detect, and remediate dependency breaking changes in seconds.
Select or Add Test Vectors
Choose from 4 pre-configured real-world Zod migration scenarios (error maps, enum coercion, required fields) or input your own custom JSON payload.
Run Differential Analysis
Click "Run Differential Analysis". ShadowBump spins up parallel Node.js child processes for zod@3 and zod@4, feeding test inputs through stdin under a 5s watchdog limit.
Review Evidence & AI Fix
Inspect side-by-side AST outputs to spot dropped properties (such as error.errors returning undefined). Copy the AI-generated before/after code migration fix directly.
Zod v3 to v4 Breaking Change Detected
username field):{
"email": "alex@company.org",
"age": 28
}Zod 4 consolidated error options into a single parameter and deprecated error.errors in favor of error.issues. Downstream code calling error.errors.map() will crash with an unhandled TypeError in production.
Test Scenarios Available in Workspace
Each scenario executes against live twin child processes with deterministic assertions.
User Registration: Custom Error Map Deprecation
Compares form validation schemas using legacy custom error options (required_error / invalid_type_error) vs Zod v4 unified error syntax.
Downstream API Adapter: error.errors Property Removal
Detects code that depends on ZodError.errors property for formatting API JSON responses.
Coercion & Numeric Edge Cases: Date & NaN Normalization
Evaluates type coercion behavior on empty strings, date objects, and NaN number parsing.
Record Dictionary Validation: Type Mismatch Reporting
Validates key-value record structures where values must satisfy numeric constraints.