EvoPolicy SDK

EvoPolicy is a high-performance, deterministic authorization engine tailored for enterprise Node.js and TypeScript ecosystems. It facilitates advanced attribute-based access control (ABAC) and role-based access control (RBAC) by evaluating policies locally within the application process. This architecture eliminates network latency and central service dependency while maintaining a robust security posture.

Technical Value Proposition

In large-scale distributed systems, authorization logic often becomes fragmented or creates performance bottlenecks due to network-based policy lookups. EvoPolicy addresses these fundamental challenges through:

1. Sub-Millisecond Evaluation: Policies are processed in-memory. Standard decision cycles complete in under 100 microseconds, ensuring critical paths remain high-speed.
2. Universal Data Interfacing: The engine is decoupled from storage. It supports seamless ingestion from local configuration (JSON/YAML), relational clusters (MySQL, PostgreSQL), and distributed NoSQL/API sources (MongoDB, GraphQL).
3. Auditable Condition Logic: A formal recursive descent parser evaluates complex constraints without unsafe script execution.
4. Security Fail-Closed Design: The SDK enforces a strict denial policy in cases of initialization failure or ambiguous rule sets.

Enterprise System Architecture

The following diagram illustrates the integration of various policy sources and the internal decision logic flow.

Architectural Components

• Logic Engine: Orchestrates the filtering and matching of policies against the evaluation context.
• IPolicyLoader Abstraction: An extensible interface for implementing custom data persistence strategies.
• Condition Parser: A secure, non-evaluative parser that validates resource and subject attributes.
• Decision Matrix: Applies Deny-Overrides logic to deliver a final authorization verdict.

Installation

npm install evopolicychecker

Technical Implementation Guide

Engine Initialization and Data Ingestion

The engine supports multiple loading strategies, allow for both static and dynamic policy management.

import { PolicyEngine, JsonPolicyLoader, CustomPolicyLoader } from 'evopolicychecker';

const engine = new PolicyEngine();

// Static file ingestion
engine.loadPolicies('./config/access_rules.json');

// Dynamic Database Integration
const fetcher = async () => {
    // Implement database-specific retrieval logic
    return await database.authorizations.findMany();
};
await engine.loadFromLoader(new CustomPolicyLoader(fetcher));

Advanced Connection Patterns

For detailed implementation and copy-paste examples for MySQL, MongoDB, PostgreSQL, and GraphQL, please refer to the Database Integration Specification.

Middleware Lifecycle Integration

EvoPolicy provides standardized middleware for Express.js to facilitate request-level authorization.

import { policyMiddleware } from 'evopolicychecker';

// Global middleware with automatic context mapping
app.use(policyMiddleware(engine));

// Granular route protection with explicit context mapping
app.post('/v1/assets/restricted', policyMiddleware(engine, (req) => ({
    subject: req.authenticatedUser,
    action: 'administer',
    resource: {
        type: 'restricted_asset',
        id: req.params.id,
        classification: req.body.level
    }
})));

Condition Operator Specification

| Operator | Categorization | Evaluation Logic | | :--- | :--- | :--- | | > , < , >= , <= | Range | Arithmetic and Chronological Comparison (ISO-8601 compatible) | | ~= | Pattern | Regular Expression matching (ECMAScript compatible) | | IN [...] | Set | Inclusion check within discrete arrays | | != | Logic | Strict inequality validation |

Performance Benchmarks

• Memory Efficiency: < 50MB baseline.
• Evaluation Throughput: 100k+ operations per second.
• Initialization Speed: ~10ms for 1,000 policy records.

For deeper insights into the internal evaluation logic and security hardening, consult the Architectural Specification.

Licensed under the ISC License. Copyright © 2026 Daksha Dubey.