Link Quote

Welcome to the Link Quote API Reference. This service provides real-time digital asset pricing and rate aggregation from multiple market data providers.

Base URL: https://api.ledgerlink.ai/v1

Overview

Link Quote is a microservice designed to aggregate and provide real-time pricing data for digital assets from multiple market data providers. It serves as a centralized quote service for the LedgerLink platform, delivering accurate and reliable market rates for cryptocurrencies and other digital assets.

Technology Stack:

• NestJS backend framework with TypeScript
• PostgreSQL database with TypeORM
• CoinMarketCap API integration
• Pyth Network (Hermes) integration
• ActiveMQ for event publishing
• RESTful API with Swagger/OpenAPI documentation

Core Capabilities

• Multi-Provider Aggregation: Fetches rates from CoinMarketCap and Pyth Network simultaneously
• Smart Provider Selection: Asset-specific or category-based provider routing
• Real-time Pricing: Current market rates with sub-second latency
• Historical Data: Store and query historical rate data
• Event Publishing: Publishes valuation events to ActiveMQ for downstream services
• Asset Management: Full CRUD operations for digital assets
• Category Management: Organize assets into configurable categories
• Provider Configuration: Flexible provider-to-asset and provider-to-category mappings

Architecture

Data Flow

1. Rate Request → Client requests rate for specific asset code
2. Asset Resolution → System looks up asset in database
3. Provider Selection → Determines which providers to query (asset-specific or category-based)
4. Price Aggregation → Fetches rates from multiple providers in parallel
5. Average Calculation → Computes weighted average from valid responses
6. Data Persistence → Stores rate in PostgreSQL with timestamp
7. Event Publishing → Publishes valuation event to ActiveMQ
8. Response → Returns aggregated rate to client

External Integrations

• CoinMarketCap: Professional cryptocurrency market data
• Pyth Network: Real-time price feeds via Hermes client
• ActiveMQ: Message queue for publishing valuation events

API Endpoints

Rate Management

• POST /rates - Create/fetch a new rate for an asset
• GET /rates - List historical rates with filtering and pagination

Asset Management

• POST /assets - Create a new digital asset
• GET /assets - List all assets with filtering
• GET /assets/:id - Get a specific asset by ID
• PUT /assets/:id - Update an existing asset
• PATCH /assets/:id/static-value - Update asset static value
• DELETE /assets/:id - Delete an asset

Category Management

• POST /categories - Create a new asset category
• GET /categories - List all categories
• GET /categories/:id - Get a specific category
• PUT /categories/:id - Update a category
• DELETE /categories/:id - Delete a category

Provider Management

• POST /providers - Create a new price provider
• GET /providers - List all providers
• GET /providers/:id - Get a specific provider
• PUT /providers/:id - Update a provider
• DELETE /providers/:id - Delete a provider

Provider Mappings

• POST /asset-providers - Map provider to asset

• DELETE /asset-providers/:assetId/providers/:providerId - Remove asset-provider mapping

• POST /category-providers - Map provider to category

• DELETE /category-providers/:id/category/:categoryId - Remove category-provider mapping

Note: There are currently no GET endpoints to list existing mappings. Mappings can be queried through the asset/category GET endpoints which include their associated providers.

Authentication

Link Quote is accessed through the Link Dashboard, which handles all authentication via the Auth Server (BFF - Backend for Frontend).

Architecture:

User → Link Dashboard → Auth Server/BFF (Authentication) → Link Quote Service

How It Works:

• Users authenticate with the Link Dashboard (username/password)
• The Auth Server validates JWT tokens and session cookies
• Authenticated requests are proxied to Link Quote at /api/link-quote/v1/*
• No role-based access control (RBAC) - all authenticated users have full access
• Link Quote service itself does not implement authentication middleware
• Direct service-to-service calls within the secure network are unauthenticated

For Direct Service Access (Development/Testing):

• Local Link Quote instances run without authentication
• Ensure proper network isolation
• Access Swagger docs at http://localhost:3000/api

See the Getting Started Guide for integration details.

Supported Digital Assets

Link Quote supports a wide range of digital assets including:

• Major Cryptocurrencies: Bitcoin (BTC), Ethereum (ETH), USDC, USDT, SOL, etc.
• Stablecoins: USDC, USDT, DAI, PYUSD
• ERC-20 Tokens: Various Ethereum-based tokens
• Custom Assets: Add any digital asset via the Asset Management API

Assets are organized into categories for efficient provider selection and rate retrieval.

Rate Providers

CoinMarketCap

• Professional cryptocurrency market data
• Real-time and historical pricing
• Requires API key

Pyth Network (Hermes)

• Decentralized oracle network
• Sub-second price updates
• On-chain price feeds

Provider selection is configurable per asset or category, with automatic failover if providers are unavailable.

Event Publishing

Link Quote publishes valuation events to ActiveMQ for real-time monitoring:

Event Types:

• VALUATION_REQUESTED - When a rate request is received
• VALUATION_PROCESSED - When rate is successfully calculated
• ERROR - When valuation fails

Events include metadata such as asset ID, value, currency, and processing details.

Next Steps

• Getting Started - Learn the basics of API integration
• API Reference - Explore detailed endpoint documentation
• Error Handling - Handle errors gracefully
• FAQ - Find answers to common questions

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Need Help? Contact helpdesk@ledgerlink.ai for assistance with your Link Quote integration.