[Blocker] Integrate custom off-ramp API for USDC → NGN withdrawal

[davedumto]

Context

app/api/withdrawals/route.ts currently has a stub initiateOfframp() that throws 'Off-ramp API not yet configured'. The Yellow Card integration was removed. A custom off-ramp API needs to be wired in to allow users to withdraw USDC to a Nigerian bank account.

What needs to be built

1. lib/offramp.ts — Off-ramp API client

export async function initiateOfframp(params: {
  amount: number          // USDC amount
  reference: string       // unique withdrawal ID
  bankAccount: {
    accountNumber: string
    bankCode: string
    accountName: string
  }
}): Promise<{ transactionId: string; status: string }>

• Calls the custom off-ramp API (endpoint to be provided)
• Signs requests with API key from env (OFFRAMP_API_KEY, OFFRAMP_API_SECRET)
• Returns a transactionId for status tracking

2. Update app/api/withdrawals/route.ts

• Replace stub with real initiateOfframp() call
• Store transactionId + status: 'pending' on the Withdrawal record
• Return meaningful error messages for insufficient balance, invalid bank account, etc.

3. Environment variables needed

OFFRAMP_API_KEY=
OFFRAMP_API_SECRET=
OFFRAMP_API_URL=https://...

Acceptance criteria

• POST /api/withdrawals successfully initiates a withdrawal via the off-ramp API
• Withdrawal record is stored with transactionId and initial status
• USDC balance is deducted from user's Stellar wallet before calling the API
• Proper error handling: insufficient funds, invalid account, API errors
• Integration test with mocked off-ramp API

[drips-wave]

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[ShantelPeters]

@ShantelPeters has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

Hi , i am shantelpeters a fullstack developer , i have looked into the issue and i would like to work on it , please kindly assign , i am ready to work .

ℹ️ Repo Maintainers: To accept this application, review their application or assign @ShantelPeters to this issue.

[drips-wave]

Congratulations, @ShantelPeters! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on March 30, 2026.

🧑‍💻 @ShantelPeters: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

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[ShantelPeters]

Hi @davedumto please kindly review my PR .. it's been open for days now

[drips-wave]

This issue has been marked as completed by a Drips Wave moderator for @ShantelPeters as part of the Stellar Wave Program's 3rd Wave 🥳

Moderator's reason: [Auto-assessed] The PR #286 successfully implements the custom off-ramp API client with HMAC signing and updates the withdrawal route logic as requested. It includes comprehensive integration tests and has been open for over 8 days without maintainer feedback, meeting the criteria for approval.

😎 @ShantelPeters: You earned 200 Points for completing this issue! After the current Wave ends, you'll be eligible for a percentage of the Wave's reward pool based on the percentage of total points you've earned. Learn more here.

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ℹ️ Note: This issue was marked complete via moderation. Points were issued even though the GitHub issue remains open.