What is Blnk?
At its core, Blnk is a double-entry accounting system designed specifically for modern fintech applications. It handles the complex financial operations that underpin digital banking, wallets, payments, lending, and trading platforms - allowing you to focus on building great user experiences.Core Capabilities
Blnk consists of three main components:Ledger
Double-entry ledger for managing balances and recording transaction workflows with features like balance monitoring, snapshots, inflight transactions, scheduling, overdrafts, and bulk operations.
Reconciliation
Automatically match external records like bank statements to your internal ledger with custom matching rules and reconciliation strategies.
Identity Management
Create and manage user identities with PII tokenization features and the ability to link to balances and transactions.
Key Features
Double-Entry Accounting
Every transaction in Blnk follows the double-entry accounting principle, ensuring your books always balance. Debits always equal credits, providing an audit trail for every financial movement.Multi-Currency Support
Natively handle multiple currencies with configurable precision. Each balance can specify its own currency and precision multiplier for accurate representation of fractional units.Inflight Transactions
Hold funds temporarily with inflight transactions - perfect for authorization holds, pending payments, or escrow scenarios. Commit or void them based on your business logic.Balance Monitoring
Set up real-time monitors on balances with custom conditions. Get notified via webhooks when balances hit thresholds, go negative, or meet any custom criteria.Historical Balances
Query balance states at any point in time. Blnk maintains snapshots and can reconstruct historical balance states from transaction history.Reconciliation Engine
Automatically reconcile internal transactions with external data sources using customizable matching rules and strategies (one-to-one, one-to-many, many-to-one).Distributed Architecture
Built for scale with Redis-backed queuing, PostgreSQL for persistence, and worker processes for background job processing. Rate limiting and connection pooling ensure stable operation under load.PII Tokenization
Securely tokenize sensitive personally identifiable information (PII) with AES-256 encryption. Link identities to balances and transactions while keeping sensitive data protected.Use Cases
Developers use Blnk to build:Wallet Management
Digital wallets with multi-currency support, transaction history, and real-time balance updates.
Digital Banking
Deposits, withdrawals, transfers, and account management for neobanks and banking-as-a-service platforms.
Order Exchange
Trading platforms for crypto, stocks, or commodities with real-time settlement and reconciliation.
Lending
Loan origination, disbursement, repayment tracking, and interest calculations.
Loyalty Points
Points accrual, redemption, and expiration tracking for rewards programs.
Escrow Payments
Hold funds in escrow with automated release conditions and dispute resolution.
AI Billing
Usage-based billing for AI/ML platforms with precise metering and invoicing.
Marketplace Payments
Split payments, commission tracking, and seller payouts for multi-vendor platforms.
Why Blnk?
Built for Compliance
Built for Compliance
Blnk’s double-entry architecture ensures your financial records are always accurate and auditable. Every transaction is immutable and traceable, meeting regulatory requirements for financial record-keeping.
Production-Ready from Day One
Production-Ready from Day One
Battle-tested features like distributed queuing, worker pools, rate limiting, and connection pooling ensure Blnk can handle production workloads from the start.
Developer-First Design
Developer-First Design
Clean REST APIs, comprehensive documentation, and real-world examples help you integrate Blnk quickly. Focus on your product, not plumbing.
Open Source & Extensible
Open Source & Extensible
Licensed under Apache 2.0, Blnk is fully open source. Customize it to your needs, contribute improvements, or deploy it anywhere.
Architecture Overview
Blnk is built with a distributed architecture designed for reliability and scale:- PostgreSQL - Primary data store for ledgers, balances, transactions, and identities
- Redis - Queue backend for transaction processing, webhooks, and background jobs
- Typesense - Search engine for fast filtering and querying across entities
- Workers - Dedicated processes for async transaction processing and webhook delivery
- API Server - REST API with authentication, rate limiting, and security headers
Next Steps
Installation
Install Blnk using Docker Compose and configure your first instance
Quick Start
Create your first ledger, balance, and transaction in minutes
Configuration
Learn about all configuration options and deployment scenarios
API Reference
Explore the complete API documentation