Maine State Credit Union API integration & OpenFinance data

1. Personal finance dashboard

A Maine-based PFM startup wants to show members a unified view across Maine State Credit Union and other US institutions. We deliver a GET /accounts + GET /accounts/{id}/transactions pair that maps to FDX Account and Transaction resources, so the dashboard can reuse the same parser for any FDX-compliant source.

2. Small-business reconciliation

A bookkeeper handling Maine small businesses pulls daily statements from the credit union into QuickBooks. The integration runs a nightly job that paginates through transactions, normalizes descriptions, and posts to a webhook the accounting tool consumes — no manual CSV downloads.

3. Member-app companion

A member-facing app surfaces low-balance alerts and bill-pay reminders. We expose balance, scheduled bill payments and posted transactions as webhooks (balance.threshold, billpay.scheduled, tx.posted) so the companion app reacts in seconds rather than polling.

4. Mobile-deposit verification

An invoicing tool needs to know when a customer has used the credit union's mobile remote deposit capture to clear a check. The RDC webhook delivers deposit status changes (submitted → cleared) plus the matched amount, so the invoice can auto-close.

5. Lending decision support

A loan-origination platform partner pulls 12 months of categorized transactions to evaluate cash flow. We deliver an FDX-style export that aligns with the Financial Data Exchange v6.4 schema, ready to plug into a credit decisioning model.

Authorization & session

POST /api/v1/mscu/auth/login
Content-Type: application/json

{
  "member_id": "********",
  "credential": "********",
  "device": { "id": "uuid", "platform": "ios" }
}

200 OK
{
  "access_token": "<jwt>",
  "refresh_token": "<opaque>",
  "expires_in": 1800,
  "mfa": { "required": false }
}

Statement / transaction query

GET /api/v1/mscu/accounts/{account_id}/transactions
  ?from=2025-09-01&to=2025-09-30
  &cursor=eyJwYWdlIjoyfQ==
Authorization: Bearer <ACCESS_TOKEN>

200 OK
{
  "account_id": "acct_8a2",
  "currency": "USD",
  "transactions": [
    {
      "id": "tx_01HZX...",
      "posted_at": "2025-09-12T14:02:11Z",
      "amount": -42.18,
      "status": "posted",
      "description": "POS - Hannaford Augusta",
      "category_hint": "groceries"
    }
  ],
  "next_cursor": "eyJwYWdlIjozfQ=="
}

Mobile deposit webhook

POST https://your-callback/mscu/rdc
X-MSCU-Signature: t=1747000000,v1=...

{
  "event": "rdc.status_changed",
  "deposit_id": "rdc_01HZY...",
  "account_id": "acct_8a2",
  "amount": 215.00,
  "status": "cleared",
  "occurred_at": "2026-05-09T15:30:11Z"
}

# Reply with HTTP 2xx within 5s, or the
# webhook will be retried with backoff.

Compliance & privacy

Maine State Credit Union is a US federally insured credit union supervised by the National Credit Union Administration (NCUA). Consumer financial data sharing in the US is governed by Section 1033 of the Dodd-Frank Act. The CFPB recognized the Financial Data Exchange (FDX) as an open-banking standard-setting body in January 2025, and FDX released API v6.4 in spring 2025; over 130 million consumer accounts are now connected through FDX. We design integrations to align with FDX data clusters and consent semantics so they remain forward-compatible regardless of the current Section 1033 rulemaking pause.

Data flow / architecture

A typical pipeline:

1. Member device or aggregator initiates an authorized session.
2. MSCU integration layer normalizes responses into FDX-shaped resources.
3. Storage (encrypted at rest, scoped per consumer consent record).
4. Output: REST API, webhook stream, or scheduled JSON/CSV export to your warehouse.

Deliverables checklist

• OpenAPI 3.1 specification covering accounts, balances, transactions, transfers, bill pay and RDC.
• Protocol & auth flow report (login, MFA challenge, token refresh, device binding).
• Runnable source for login + statement endpoints in Python and Node.js.
• Webhook receiver template with signature verification.
• Postman collection and contract tests.
• Compliance brief: NCUA context, FDX mapping, consent and retention guidance.

Engagement workflow

1. Scope confirmation: pick the data and actions you need from the inventory above.
2. Protocol analysis & API design (2–5 business days).
3. Build and internal validation (3–8 business days).
4. Documentation, sample clients, and contract tests (1–2 business days).
5. Typical first delivery in 5–15 business days; aggregator approvals may extend the timeline.

About OpenFinance Lab

We are an independent technical studio focused on App interface integration and authorized API integration. The team brings hands-on experience from US and EU banks, payment processors, mobile protocol analysis, and cloud platforms. For credit union work specifically, we combine knowledge of NCUA supervision, FDX data clusters, and aggregator coverage so that the integration we ship is realistic to operate, not just runnable on a demo day.

• Banking, credit union, and fintech API integrations end-to-end.
• Protocol analysis for Android and iOS mobile apps.
• Custom Python / Node.js / Go SDKs and test harnesses.
• Source code delivery from $300 — runnable API source code and full documentation; pay after delivery upon satisfaction.
• Pay-per-call API billing — access our hosted endpoints and pay only per call, no upfront cost.

Contact

To request a quote or share your target requirements for Maine State Credit Union or a related app, open our contact page.

Contact page