Greylock Federal Credit Union API integration (FDX / OpenBanking)

Deliverables checklist

• OpenAPI 3.1 specification for every endpoint we build
• Protocol & auth-flow report (OAuth handshake, MFA challenge map, cookie chain)
• Runnable source for login, account list, transactions and eDocument download in Python and Node.js
• Automated pytest / mocha test suite plus a Postman collection
• Compliance guidance covering CFPB Section 1033, NCUA member-data expectations and Massachusetts 201 CMR 17.00 data-protection rules
• Quicken / QuickBooks OFX reconnection profile valid after the May 2025 Alkami conversion

Two engagement models

• Source code delivery from $300 — runnable Greylock FCU API source and documentation; payment is only released after you have verified the build against a sandbox or test member account.
• Pay-per-call API billing — call our hosted Greylock FCU integration endpoints with metered billing, no setup fee, suitable for teams that prefer usage-based pricing or short-lived projects.

1. Bookkeeping & reconciliation sync

A small business in Pittsfield, MA holds a Greylock business checking and a loan account. Our integration polls /accounts and /transactions hourly, normalises each transaction into an FDX Transaction object, and pushes it to QuickBooks Online via the QBO Bank Feed format. This re-establishes the QuickBooks link that was disrupted by the May 2025 Alkami conversion.

Fields used: postedTimestamp, amount, memo, categorization.category, checkNumber.

2. Member-level credit-card and loan health

A personal-finance app pulls Greylock loan balance, APR, next-due date and minimum payment, and overlays them with the member's free credit-score tile. The output is a "debt-payoff timeline" the member can act on. Maps cleanly onto FDX Loan and CreditCard resources.

Fields used: principalBalance, interestRate, nextPaymentAmount, nextPaymentDate, creditScore.

3. Zelle and ACH event streaming for fraud watch

A fintech that monitors elderly-relative accounts subscribes to a webhook channel we emit. Whenever a Zelle send leaves the account or an external transfer is initiated, the event is pushed to a fraud-scoring engine. The engine can call a "freeze" RPC back through our API to halt the transfer if the score crosses a threshold.

Fields used: event.type (zelle.sent, ach.initiated), counterparty.token, amount, deviceFingerprint.

4. Tax season eDocument harvesting

An accounting firm authorised by 40+ Greylock members runs a yearly job that walks /edocuments?type=tax&year=2025 for each consented member and stores the resulting 1099-INT and 1098 PDFs in a Drake Tax archive. Each retrieval is logged with the consent-token id for audit.

Fields used: documentType, year, memberId, checksum, downloadUrl (short-lived).

5. Mobile deposit RDC into an AR system

A landlord in Hudson, NY collects rent checks and uses the Greylock mobile-deposit feature. Our integration intercepts the resulting deposit event, matches the OCR-extracted check amount and memo against the open-invoices ledger, and marks the matching invoice as paid in the property-management system.

Fields used: depositId, amount, checkImage.front, ocr.memo, holdReleaseDate.

Authenticate & mint a session

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

{
  "username": "member-handle",
  "password": "<hashed>",
  "device_fingerprint": "abc123",
  "mfa": { "channel": "sms", "code": "482910" }
}

// Response (200)
{
  "access_token": "eyJhbGciOi...",
  "refresh_token": "rt_8h2k...",
  "expires_in": 1800,
  "member_id": "GRLK-7782",
  "scope": ["accounts:read","transactions:read","edocs:read"]
}

FDX-aligned statement pull

// Request
GET /api/v1/greylock/accounts/{accountId}/transactions
  ?startDate=2025-04-01
  &endDate=2025-04-30
  &pageSize=200
Authorization: Bearer <ACCESS_TOKEN>
X-Consent-Id: cnsnt_2026_05_11_xyz

// Response (200) — abbreviated, FDX 6.4 shape
{
  "transactions": [
    {
      "transactionId": "txn_8821",
      "postedTimestamp": "2025-04-12T14:08:31Z",
      "amount": -42.18,
      "currency": "USD",
      "memo": "STOP & SHOP PITTSFIELD MA",
      "category": "GROCERIES",
      "runningBalance": 4218.55
    }
  ],
  "page": { "next": "cursor:eyJvZmZzZXQ..." }
}

Webhook: new Zelle send

// Outbound webhook fired by our integration server
POST https://your-app.example.com/hooks/greylock
X-OFL-Signature: sha256=...
Content-Type: application/json

{
  "event": "zelle.sent",
  "memberId": "GRLK-7782",
  "amount": 75.00,
  "counterparty": { "token": "jane@example.com" },
  "status": "completed",
  "occurredAt": "2026-05-11T17:42:08Z",
  "consentId": "cnsnt_2026_05_11_xyz"
}

// Expected ack: 200 within 5s; otherwise we retry with
// exponential backoff (5s, 30s, 5m, 30m).

Regulations we map to

US consumer-permissioned financial data sharing now sits primarily under the CFPB's Personal Financial Data Rights rule (Section 1033 of the Dodd-Frank Act), released in October 2024 and naming the Financial Data Exchange (FDX) as the recognised standard-setting body. The CFPB paused active enforcement in July 2025 pending market feedback, but most credit unions including Greylock have continued aligning to FDX 6.4 (released June 2025) on the assumption that the rule will resume.

For Greylock specifically, we additionally align to NCUA member-data and information-security expectations, GLBA Safeguards Rule controls, and the Massachusetts data-protection regulation 201 CMR 17.00 (a relevant fact because Greylock is chartered in Pittsfield, MA).

How we operate inside those constraints

• Every API call carries an explicit member-consent token issued out-of-band, never reused across members.
• Data minimisation is enforced at the gateway: scopes such as transactions:read cannot bleed into edocs:read.
• We keep an immutable audit log of every retrieval, with member id, purpose code, requesting IP and bytes returned — exportable for a CFPB or NCUA inquiry.
• At-rest encryption is AES-256, in-transit is TLS 1.3, and PII never leaves the customer's tenancy when self-hosted.

About us

OpenFinance Lab is an independent studio focused on fintech and consumer-permissioned financial data. Our engineers have shipped integrations for US credit unions, community banks, neobanks and aggregators, and have spent the last three years tracking the CFPB Section 1033 and FDX rollout closely enough to know which endpoints are stable and which still need a bridge.

• Payments, digital banking, lending, and bookkeeping API integrations
• Custom Python / Node.js / Go SDKs and test harnesses
• Protocol analysis, OAuth/MFA handshake reverse engineering and re-implementation
• Compliance-aware delivery: CFPB 1033, NCUA, GLBA, state-level rules (e.g. 201 CMR 17.00)
• Source-code delivery from $300 — runnable API source and full documentation, payable on satisfaction
• Pay-per-call hosted API — usage-based pricing with no upfront cost

Contact

For quotes or to submit your target app and requirements, open our contact page:

Contact page

We typically respond within one business day. Please include the target app (e.g. Greylock Federal Credit Union), the data scope you need (transactions, eDocuments, Zelle events, …) and whether you prefer source-code delivery or pay-per-call hosting.

Engagement workflow

1. Scope confirmation — exact data fields needed (e.g. share-draft transactions, 1099-INT PDFs, Zelle events).
2. Protocol analysis & API design (2–5 business days; mapped to FDX 6.4 where possible).
3. Build and internal validation against a sandbox member account (3–8 business days).
4. Docs, sample code, and pytest / mocha test cases (1–2 business days).
5. First delivery typically 5–15 business days; reconnection profiles for Quicken / QuickBooks ship as a separate one-day patch.

FAQ

What do you need from me to start a Greylock FCU integration?

How long does delivery take for a Greylock FCU API drop?

How do you handle CFPB 1033 and NCUA compliance?

Can you connect Greylock data to Quicken or QuickBooks after the May 2025 conversion?