Identifying Users by Internal User ID

Overview

Coinflow identifies your users by an internal user ID that you provide.

Implementation

When using the API, pass your internal user ID in the header:

Header: x-coinflow-auth-user-id: YOUR_USER_ID
Value: Any unique, stable identifier from your system (database ID, customer ID, username, etc.)

Example API Call

$ curl --request POST \
>   --url https://api-sandbox.coinflow.cash/api/withdraw/kyc \
>   --header 'Authorization: YOUR_API_KEY' \
>   --header 'x-coinflow-auth-user-id: user_12345' \
>   --header 'Content-Type: application/json' \
>   --data '{
>     "email": "user@example.com",
>     "country": "US",
>     "firstName": "Jane",
>     "lastName": "Doe"
>   }'

User ID Requirements

Must Haves

Required characteristics for user IDs

Unique per user - No duplicate IDs across your platform
Stable and permanent - Never changes for a given user
Consistent format - Alphanumeric strings recommended
Privacy-safe - Don’t use PII (emails, SSNs, names)

✅ Good examples: user_12345, cust_abc123, uid-9876

Best Practices

Recommendations for robust identification

Use database primary keys or UUIDs
Avoid sequential IDs that reveal user count
Store Coinflow’s withdrawer ID alongside your user ID
Document the ID format in your integration
Test with real-world ID formats early

⚠️ Avoid: emails, usernames (can change), sequential numbers

Payout Flows Using User ID Identification

Merchant Payout from Coinflow In-App Wallet

Most common flow for platforms managing user balances:

Track user earnings - Store balances in your database
User requests payout - Via your platform’s UI
KYC verification - One-time identity check (if not done)
Link bank account - User adds payout destination
Merchant initiates payout - You call Coinflow API with user ID
Funds disbursed - From Coinflow wallet to user’s bank

→ See Merchant Payout (Coinflow Wallet) for implementation details

Common Questions

Q: Can I use email addresses as user IDs? A: While possible, it’s not recommended. Emails can change, creating issues with Coinflow records. Use stable database IDs instead.

Q: What if I have multiple user ID formats across systems? A: Choose one canonical format for Coinflow integration. Map your various IDs to a single stable identifier in your integration layer.

Q: Can I change a user’s ID after they’ve completed KYC? A: No. Once a user completes KYC with a specific user ID, that ID is permanently associated with their Coinflow identity. Plan your ID strategy before going live.

Q: Do I need to store Coinflow’s withdrawer ID? A: Not required, but recommended for debugging and customer support. Store it alongside your user ID for reference.

Q: Can one user have multiple IDs? A: Each unique user ID creates a separate Coinflow identity. If you need to consolidate user accounts, contact Coinflow support for guidance.