The Complete Platform for Crypto-to-Card Finance
Baanx API is a multi-tenant gateway that bridges cryptocurrency wallets with traditional card payments. Whether you’re building a neobank, crypto exchange, or DeFi platform, our API provides everything you need to offer seamless financial services to your users.OAuth 2.0 with PKCE
Secure authorization flow with hosted UI or custom authentication
Dual Wallet Models
Custodial (platform-managed) and non-custodial (user-controlled) options
Physical & Virtual Cards
Issue and manage debit cards linked to crypto wallets
Blockchain Delegation
Grant spending authority while maintaining full custody on EVM and Solana
Consent Management
GDPR/CCPA-compliant consent tracking with complete audit trails
What Can You Build?
Crypto Wallet Apps
Build wallets with integrated card payments for seamless crypto-to-fiat conversion
DeFi Platforms
Enable users to spend crypto with cards while maintaining self-custody
Neobanks
Launch digital banks with crypto backing and traditional card rails
Exchange Integrations
Add card services to your crypto exchange with custodial wallets
Third-party Apps
Integrate with existing Baanx accounts using OAuth 2.0
Payment Solutions
Create innovative payment experiences combining crypto and cards
Choose Your Integration Path
Building with Baanx requires two key decisions:Step 1: OAuth Implementation Mode
Choose how your users will authenticate:OAuth API Mode (Recommended)
Full control over authentication UX
- ✅ Custom branded login experience
- ✅ Native mobile app integration
- ✅ Complete UI control
- ✅ Headless/API-first systems
- ❌ More integration steps (5 vs 4)
- ❌ You handle user credentials
OAuth Hosted UI
Quick setup with pre-built login
- ✅ Fastest implementation (~30 min)
- ✅ No credential handling
- ✅ Built-in security
- ✅ Perfect for web apps
- ❌ Standard UI (limited branding)
- ❌ Requires redirect flow
Step 2: Wallet Model
Choose how keys are managed (independent of OAuth choice):Custodial Wallets
Platform manages keys
- ✅ Simpler integration
- ✅ No wallet software needed
- ✅ Direct card linking
- ✅ Whitelist-based security
- ❌ Platform custody required
- ❌ Limited withdrawal flexibility
Non-Custodial Wallets
Users control their own keys
- ✅ True self-custody
- ✅ On-chain verification
- ✅ Flexible withdrawals
- ✅ DeFi-native approach
- ❌ More complex setup
- ❌ Requires wallet software (MetaMask, Phantom)
- ❌ Delegation flow needed
Understanding the relationship: OAuth handles authentication (who the user is), while the wallet model handles key custody (who controls the crypto). All integrations use OAuth - you just pick the mode and wallet model that fits your use case.
Mobile App with Custodial Wallets
Mobile App with Custodial Wallets
Example: Crypto exchange mobile app with card issuanceYour choices:Implementation time: ~4 hours
- OAuth: API Mode (custom login UI in your app)
- Wallet: Custodial (you manage keys, users get simplicity)
1
Implement OAuth API Mode
Follow API Mode guide for custom login flow
2
Set Up Custodial Wallets
Learn about platform-managed wallets
3
Link Cards to Wallets
Enable card linking
4
Issue Cards
Use card operations to order cards
Web App with DeFi Self-Custody
Web App with DeFi Self-Custody
Example: DeFi platform where users control their keysYour choices:Implementation time: ~4 hours
- OAuth: Hosted UI (quick web integration)
- Wallet: Non-Custodial (users maintain custody via MetaMask/Phantom)
1
Implement OAuth Hosted UI
Follow Hosted UI guide for redirect flow
2
Understand Non-Custodial Model
Review non-custodial wallets
3
Implement Delegation Flow
Follow delegation guide
Neobank with Custom UX + Platform Custody
Neobank with Custom UX + Platform Custody
Example: Digital bank with white-label crypto cardsYour choices:Implementation time: ~3 hours
- OAuth: API Mode (fully branded experience)
- Wallet: Custodial (platform security, user simplicity)
1
Set Up OAuth API Mode
Implement API Mode with your branding
2
Configure Custodial Wallets
Set up internal wallets
3
Link and Issue Cards
Enable card operations
Third-Party Integration (OAuth Only)
Third-Party Integration (OAuth Only)
Example: Partner app accessing user accountsYour choices:Implementation time: ~30 minutes
- OAuth: Hosted UI (simplest, most secure for third parties)
- Wallet: Depends on the main platform’s configuration
1
Understand OAuth Flow
Learn OAuth 2.0 with PKCE
2
Implement Hosted UI
Follow Hosted UI guide
3
Make API Calls
Use access tokens to fetch user data
Start with OAuth Quickstart
Get up and running quickly
I'm exploring what's possible
I'm exploring what's possible
Perfect for: Evaluating Baanx for your use caseStart with these high-level overviews:
OAuth Options
API Mode vs Hosted UI - understand the differences
Wallet Models
Custodial vs non-custodial - choose based on your users
Card Capabilities
Physical/virtual cards, PIN management, transactions
Delegation Flow
How non-custodial users spend crypto with cards
New to crypto integration? We recommend starting with OAuth API Mode + Custodial Wallets for the best balance of control and simplicity.
Key Features
Flexible Authentication
OAuth 2.0 with PKCE
Industry-standard authorization for third-party integrations with hosted UI or custom flows
Direct Login API
Traditional username/password authentication for first-party applications
Wallet Options for Every Use Case
Custodial Wallets
Platform manages keys - Simpler integration, built-in security, whitelist-based withdrawals, direct card linkingLearn more →
Non-Custodial Wallets
Users control keys - True self-custody, blockchain delegation, multi-wallet support, on-chain verificationLearn more →
Card Management
Physical & Virtual Cards
Issue both physical and virtual debit cards
Secure Access
One-time tokens for viewing sensitive card details
PIN Management
Users can view and set PINs securely
Transaction History
Real-time transaction tracking and statements
Card Controls
Freeze/unfreeze cards, manage limits
Status Tracking
Monitor activation, delivery, and usage
Blockchain Delegation
EVM Chains
Support for Linea and Ethereum networks with smart contract delegation
Solana
Native Solana integration with signature-based proof of ownership
Consent Management
Regulatory Compliance
GDPR, CCPA, and E-Sign Act compliance with immutable audit trails for all consent changes
Flexible Policies
US and Global policy types with region-specific requirements (eSignAct for US users)
Complete Audit Trail
Track all consent changes with timestamps, IP addresses, and user agent information
User Control
Allow users to grant, deny, and revoke consent for marketing, SMS, and email notifications
Multi-Tenant Architecture
The Baanx API automatically routes requests to your environment based on your credentials. Each client receives unique keys for sandbox and production environments.Required Headers
| Header | Required | Purpose |
|---|---|---|
x-client-key | Always | Your public API key - identifies your tenant |
Authorization | Authenticated endpoints | Bearer token for user context |
x-secret-key | OAuth endpoints only | Secret key for client authentication |
x-us-env | Optional | Set to true for US region routing |
Why Developers Choose Baanx
Flexibility
Choose custodial or non-custodial models based on your business needs and user preferences
Security First
OAuth 2.0 with PKCE, multi-tenant isolation, one-time tokens, and blockchain verification
Developer Experience
Clear documentation, OpenAPI specification, practical examples, and responsive support
Production Ready
Battle-tested infrastructure handling real card transactions and blockchain operations
Popular Integration Combinations
API Mode + Custodial
Mobile apps, neobanks, exchangesCustom UX with platform-managed keysOAuth: API Mode | Wallet: CustodialTime: ~4 hours
Hosted UI + Custodial
Web apps, quick integrationsFast setup with platform securityOAuth: Hosted UI | Wallet: CustodialTime: ~2 hours
API Mode + Non-Custodial
DeFi mobile apps, Web3 walletsCustom UX with user-controlled keysOAuth: API Mode | Wallet: Non-CustodialTime: ~6 hours
Hosted UI + Non-Custodial
DeFi web platformsQuick OAuth setup with self-custodyOAuth: Hosted UI | Wallet: Non-CustodialTime: ~4 hours
Explore the Documentation
- Guides
- API Reference
Conceptual documentation organized by domain
- OAuth 2.0 & Authentication - Secure authorization flows
- User Management - Registration, profiles, verification
- Consent Management - GDPR/CCPA-compliant consent tracking
- Wallet Management - Custodial and non-custodial options
- Non-Custodial Delegation - Blockchain delegation flows
- Card Operations - Card issuance and management
Browse All Guides
Start with conceptual documentation
Getting Started Checklist
1
Get API Credentials
Contact your account manager to receive your
x-client-key and x-secret-key for sandbox and production2
3
Choose Wallet Model
Select Custodial (platform-managed) or Non-Custodial (user-controlled) based on your custody model
4
Implement Authentication
Follow the OAuth guide for your chosen mode to set up user authentication
5
Set Up Consent Management
Implement Consent Management to track user consent for GDPR, CCPA, and E-Sign Act compliance. Consent collection is required during user registration before accessing card or wallet features.
6
Test in Sandbox
Use your sandbox credentials to test the full integration before going live, including consent collection flows
7
Go to Production
Schedule an operational “go live” meeting with your account manager to review your integration and initiate the approval process for production credentials
Need Help?
Integration Support
Contact your technical account manager for implementation assistance
API Issues
Check troubleshooting guides or contact support at [email protected]
OpenAPI Spec
Download the complete OpenAPI 3.1 specification for your tools
Ready to get started? Most developers begin with the OAuth Quickstart to understand authentication, then move to their specific use case (wallets, cards, or delegation).