Frost Bank API Integration & OpenBanking Data Services

Scenario 1 — Texas SMB accounting sync

A San Antonio-based SMB uses QuickBooks Online and holds all operating deposits at Frost Bank. We bind the business owner’s account via Plaid Exchange, then run a nightly job calling /transactions over the last 24 hours. The job writes each line to QuickBooks with the memo field already captured in the Frost app. This replaces manual CSV exports and closes the books in hours instead of days.

DataTransactions, running balance, memos  MappingOpenFinance → QBO SyncToken

Scenario 2 — Mortgage pre-qualification

A fintech lender needs three months of statements plus cleared-check images to verify rent history. The borrower authorizes Frost through a Plaid OAuth flow; we call a statement API returning monthly PDFs and a cleared-check endpoint that mirrors the in-app “view and zoom, save and print” artifacts. The underwriter receives signed URLs with a 15-minute TTL.

DataeStatements, cleared checks  MappingCFPB 1033 authorized transfer

Scenario 3 — Consent & 1033 data-rights dashboard

A bank-agnostic dashboard lets the consumer see every app with Plaid access to their Frost account. We read the Manage Account Connections inventory, present each grant with scope and date, and expose a one-click revoke button that calls the same endpoint the Frost app uses. This is a direct implementation of the “personal financial data rights” CFPB finalized in October 2024.

DataPlaid grants  MappingSection 1033 consumer portal

Scenario 4 — Treasury liquidity webhook

A mid-market CFO needs a push notification whenever any Frost account drops below a threshold. We deploy a webhook worker that polls balance + upcoming-payment activity every five minutes and emits an event to Slack and an ERP. Because upcoming transfers are already surfaced in the app, forecasts are based on scheduled, not historical, data.

DataBalances, bill-pay schedule  MappingOpenBanking variable-balance event

Scenario 5 — Expense & fraud response for travel teams

A corporate travel platform integrates the 1,700+ Frost ATM directory into its in-app map so employees route to no-fee cash. If a card is reported suspicious, the same session calls the temporary-freeze toggle and fires a Zelle-style reimbursement to the cardholder’s backup account until a replacement arrives.

DataATM directory, card freeze, P2P transfer  MappingOpenData geospatial + OpenFinance action

1. OAuth token exchange (Plaid Exchange-aligned)

POST /api/v1/frost/auth/token
Content-Type: application/json

{
  "grant_type": "authorization_code",
  "code": "PL_...redacted",
  "client_id": "your_client_id",
  "code_verifier": "<PKCE verifier>",
  "redirect_uri": "https://yourapp.com/cb"
}

200 OK
{
  "access_token": "fb_at_...",
  "refresh_token": "fb_rt_...",
  "expires_in": 1800,
  "scope": "accounts:read transactions:read statements:read",
  "consent_id": "cns_2026_04_a91b"
}

2. Paginated transaction history

GET /api/v1/frost/accounts/{account_id}/transactions
  ?from=2026-03-01&to=2026-03-31&cursor=eyJwIjoyfQ
Authorization: Bearer <ACCESS_TOKEN>

200 OK
{
  "account_id": "acc_chk_8821",
  "transactions": [
    {
      "id": "txn_9f21",
      "posted_at": "2026-03-28T14:02:11Z",
      "amount": -42.57,
      "currency": "USD",
      "running_balance": 4310.88,
      "memo": "HEB #412 San Antonio",
      "category": "groceries",
      "status": "posted"
    }
  ],
  "next_cursor": "eyJwIjozfQ"
}

3. Balance-drop webhook

POST https://yourapp.com/hooks/frost
X-Frost-Signature: t=1714656000,v1=3b2f...
Content-Type: application/json

{
  "event": "balance.threshold_crossed",
  "account_id": "acc_chk_8821",
  "balance": 820.13,
  "threshold": 1000.00,
  "triggered_at": "2026-04-20T09:14:07Z",
  "upcoming_debits": [
    { "payee": "CPS Energy", "amount": 186.40, "date": "2026-04-22" }
  ]
}

// Verify with HMAC-SHA256 of timestamp.payload

Deliverables checklist

• OpenAPI / Swagger 3 spec for every Frost endpoint we expose
• Protocol analysis report: OAuth scopes, token lifecycles, PIN/biometric session handling
• Runnable source code (Python / Node.js / Go) with authentication helpers
• Postman collection with pre-wired Plaid Exchange OAuth flows
• Automated tests (pytest / Jest) plus load-test scripts
• Compliance brief covering CFPB 1033, GLBA, FDIC disclosures, and Texas privacy law
• Operational runbooks for consent revoke, rotation, and incident response

Engagement models

Source-code delivery from $300 — we hand over runnable API source code, documentation, and tests; you pay after delivery once the agreed acceptance tests pass.

Pay-per-call API billing — no upfront fee; you consume our hosted Frost Bank endpoints and pay only for successful calls. Ideal for pilots, usage-spiky workloads, or teams that do not want to self-host.

About our studio

We are an independent technical studio specializing in App interface integration and authorized API integration. Our engineers come from banking, payments, mobile security, and data engineering backgrounds, and we have shipped production OpenFinance integrations against US, EU, LATAM, and APAC financial apps.

• Core domains: retail & commercial banking, payments, insurtech, e-commerce, travel, messaging
• Deep familiarity with Plaid, MX, Finicity, and direct OpenBanking protocols
• Mobile reverse engineering and traffic analysis on Android and iOS with strict consent boundaries
• End-to-end pipeline: discovery → protocol analysis → build → QA → compliance hand-off
• Two transparent engagement models (source-code from $300 or pay-per-call hosted API)

Contact

Ready to scope a Frost Bank integration or bundle it with adjacent apps like Plaid, QuickBooks, or another US bank? Share your target app and requirements through our contact page.

Open the contact page

Typical first reply within one business day. NDAs and data-processing agreements available on request.

Engagement workflow

1. Scope confirmation: target endpoints, consent model, compliance constraints (1–2 business days).
2. Protocol analysis & API design for Frost Bank data surfaces (2–5 business days).
3. Build, hardening, and internal validation against sandbox or authorized test accounts (3–8 business days).
4. Documentation, Postman collection, automated tests, and compliance brief (1–2 business days).
5. Typical first delivery window: 5–15 business days. Complex cross-bank aggregations may extend.

FAQ

What do you need from me to start?

How do you handle consent and revocation?

Can you integrate Frost alongside Chase, USAA, Ally, or Capital One?

What happens if Frost changes its login or protocol?