Main Street Bank Mobile API integration (FDX / OpenBanking)

Protocol analysis, FDX-aligned endpoints and runnable source for balances, statements, bill pay, transfers and mobile check deposit.

From $300 · Pay-per-call available
OpenData · OpenFinance · FDX · Section 1033 · Protocol analysis

Move Main Street Bank Mobile data into your accounting, ledger and reporting stack

Main Street Bank Mobile is a US community-bank application that holds checking and savings balances, mortgage and auto loan position data, transfer and bill-pay history, account alerts and a photo-based mobile check deposit pipeline. We turn those screens into structured, queryable APIs that map cleanly to the Financial Data Exchange (FDX) resource model used across United States open banking.

Account & balance APIs — Pull current and available balances on every linked checking, savings, mortgage and auto-loan account; mirror Fast Balances semantics so dashboards never need to log a customer in twice.
Statement & transaction APIs — Date-ranged transaction history with paging, descriptor parsing and category tags; deliver to ERP, accounting platforms, or CSV/JSON/Excel exports.
Transfers, bill pay and recurring payments — Programmatic ACH-style transfers between owned accounts and to other financial institutions; managed bill list, scheduled payments and cancellation hooks.
Mobile remote deposit (mRDC) — Server-side wrapper around photo-of-check submission with front/back image upload, deposit-status webhooks and reconciliation against the posted ledger entry.

What we deliver

Deliverables checklist

  • OpenAPI 3.1 / Swagger specification covering every endpoint
  • Protocol report: device registration, token-binding, refresh chain, error map
  • Runnable Python and Node.js reference clients (auth, balances, statements, transfers, mRDC)
  • Postman collection, automated integration tests and synthetic fixtures
  • Section 1033 / FDX mapping notes so your gateway can claim conformance with minimal rework
  • Compliance and consent-management guidance, including data-minimisation and retention defaults

Two engagement models

Pick whichever billing shape matches your team. Source-code delivery is best for teams that want to own and host the integration themselves; pay-per-call is best for teams that just need answers and prefer an OpEx line item.

  • Source code delivery from $300 — runnable API source code plus full documentation; pay after delivery upon satisfaction.
  • Pay-per-call API billing — call our hosted endpoints and pay only for the calls you make, no upfront fee.

Data available for integration

The Main Street Bank Mobile app exposes the following structured data when accessed through the customer's authenticated session. The table below maps each item to the screen it lives on, the granularity you can expect, and the most common downstream use that justifies the integration.

Data typeSource screen / featureGranularityTypical use
Checking & savings balancesAccounts overview / Fast BalancesCurrent & available, per account, near real-timeCash-position dashboards, treasury sweeps
Loan balances (mortgage, auto, other)Accounts overviewOutstanding principal, next due dateNet-worth tracking, debt-to-income reporting
Transaction historyAccount detail viewPer-line: date, amount, descriptor, statusBookkeeping, reconciliation, fraud analytics
Bill pay payees & schedulesBill pay / recurring paymentsPayee, amount, frequency, next-run dateAP automation, cashflow forecasting
Transfers (internal & external)Transfers menuSource/destination, amount, ACH timingMulti-bank cash sweeps, payroll funding
Mobile check deposits (mRDC)Deposit Funds (photo capture)Image pair, MICR-derived metadata, statusReceivables capture, audit evidence
Account alerts & preferencesMy profile / alertsTrigger type, threshold, channelRisk monitoring, customer-experience analytics
Device & biometric bindingTouch ID / Face ID enrolmentDevice fingerprint, enrolment statusStep-up auth design, fraud prevention

Typical integration scenarios

1. Small-business bookkeeping sync

A QuickBooks or Xero customer needs nightly imports of every Main Street Bank Mobile transaction to close the books on time. We wrap the Statement & Transaction APIs behind a webhook so each posted line lands as a categorised entry; the source field maps to FDX transactions[].description while the running balance is reconciled against accounts[].balance.available.

2. Treasury cash-position dashboard

A finance team running multiple regional banks (e.g. one Main Street Bank Mobile login plus several larger national apps) needs a single-pane view. The Balance API streams current and available balances at five-minute intervals, normalised to FDX balanceAsOf timestamps so a treasurer can sweep idle cash without manual logins.

3. Mobile check deposit automation

An accounts-receivable team receives paper checks at a back office. We expose an internal endpoint that accepts front and back images and forwards them through the same mRDC pipeline the consumer app uses; deposit status is then posted to the AR ledger so the receivable is closed only when the bank confirms posting (mirroring how Treasury Prime, Jack Henry and similar US RDC platforms model the resource).

4. Compliance & audit data room

A regulated fintech building on top of Main Street Bank Mobile data needs an immutable audit trail. We attach a consent-record store to every API call, log the requesting actor, retention window and FDX scope, and emit signed JSON receipts so a Section 1033 auditor can trace which field was read by whom and when.

5. Personal-finance & net-worth app

A consumer PFM app wants to add a community-bank connector to broaden coverage beyond the major aggregators. We deliver a connector that performs OAuth-style token exchange, pulls checking, savings, mortgage and auto loan balances, and emits FDX-shaped JSON the PFM app can drop into its existing pipeline alongside Plaid, MX or Finicity feeds.

Technical implementation

Authentication & token refresh

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

{
  "grant_type": "password",
  "username": "alice@example.com",
  "password": "********",
  "device_id": "ios-9f1c-...-3b",
  "biometric_bound": true
}

200 OK
{
  "access_token": "eyJhbGciOi...",
  "refresh_token": "rt_8d2b...",
  "expires_in": 1800,
  "scope": "accounts.read transactions.read transfers.write rdc.write"
}

Statement query (FDX-aligned)

POST /api/v1/msb/statement
Authorization: Bearer <ACCESS_TOKEN>
Content-Type: application/json

{
  "account_id": "chk_4012",
  "from_date": "2026-04-01",
  "to_date":   "2026-04-30",
  "page_size": 200
}

200 OK
{
  "account": {"id":"chk_4012","type":"DEPOSIT_CHECKING"},
  "transactions": [
    {"postedDate":"2026-04-03","amount":-42.10,"description":"ACH BILLPAY EVERSOURCE","status":"POSTED"},
    {"postedDate":"2026-04-05","amount": 2500.00,"description":"PAYROLL ACME INC","status":"POSTED"}
  ],
  "balanceAsOf":"2026-04-30T23:59:59-04:00",
  "balance": {"current": 5817.42, "available": 5810.00}
}

Mobile check deposit (mRDC) submission

POST /api/v1/msb/check_deposits
Authorization: Bearer <ACCESS_TOKEN>
Content-Type: multipart/form-data

front_image=@check_front.jpg
back_image=@check_back.jpg
account_id=chk_4012
amount=185.00

202 Accepted
{
  "deposit_id": "dep_2026_05_02_abc",
  "status": "PENDING",
  "submitted_at": "2026-05-02T15:21:08Z"
}

# poll status
GET /api/v1/msb/check_deposits/dep_2026_05_02_abc -> {"status":"POSTED"}

Webhook: deposit and transfer events

POST https://your-host.example/webhooks/msb
X-MSB-Signature: t=1714665668,v1=...

{
  "event": "deposit.posted",
  "deposit_id": "dep_2026_05_02_abc",
  "account_id": "chk_4012",
  "amount": 185.00,
  "posted_at": "2026-05-02T19:04:11Z"
}

Signed webhooks let your accounting system close out an open receivable as soon as the bank acknowledges posting, instead of polling on a timer.

Compliance & privacy

Regulatory framing

United States open banking is governed by Section 1033 of the Dodd-Frank Act, with the Consumer Financial Protection Bureau (CFPB Personal Financial Data Rights) issuing the Personal Financial Data Rights rule. In January 2025 the CFPB recognised the Financial Data Exchange (FDX) as a standard-setting body, and FDX v6.4 (released June 2025) added explicit Section 1033 consent and disclosure fields. Our implementations target FDX naming, consent records and dispute-handling so that adopters can claim "indicia of compliance" with minimal rework.

How we handle consent & data minimisation

  • Every call is scoped — a balances-only consumer never touches transaction descriptors.
  • Refresh tokens are revocable and tied to a single device fingerprint.
  • Deposit images are stored encrypted at rest with configurable retention windows.
  • Audit logs record actor, scope, fields read and timestamp for each session.
  • State privacy laws (CCPA/CPRA, NYDFS Part 500 where applicable) are honoured at the schema level, including subject-access and deletion endpoints.

Data flow & architecture

The reference architecture is intentionally small. A four-node pipeline keeps debugging simple and makes regulator review tractable:

  1. Main Street Bank Mobile (client surface) — the authenticated user session that originates requests, including biometric bind.
  2. OpenFinance Lab gateway — handles OAuth-style token exchange, FDX-shaped routing, signed webhooks and per-call audit.
  3. Consumer storage — your data warehouse (Postgres, Snowflake, BigQuery) or accounting platform (QuickBooks, Xero, NetSuite).
  4. Reporting / analytics — dashboards, treasury sweeps, AR/AP reconciliation, or downstream PFM/ERP modules.

Each hop emits a signed JSON receipt; the gateway is the only component that holds bank credentials, so the rest of the stack only ever sees redacted tokens and FDX-shaped responses.

Market positioning & user profile

Main Street Bank Mobile is a US community-bank application aimed at retail and small-business customers who hold their primary checking, savings and consumer-loan accounts at a regional institution rather than a national bank. Its user base skews North American, predominantly the Northeast and Mid-Atlantic, with both Android and iOS support. Compared with the high-volume national apps it competes with on convenience features (Touch ID/Face ID, Fast Balances, photo-based deposits) rather than on brand reach, which makes it a natural connector target for fintechs that want to broaden coverage beyond Plaid's tier-one bank list.

Screenshots

Click any screenshot to enlarge.

Main Street Bank Mobile screenshot 1 Main Street Bank Mobile screenshot 2 Main Street Bank Mobile screenshot 3 Main Street Bank Mobile screenshot 4 Main Street Bank Mobile screenshot 5 Main Street Bank Mobile screenshot 6 Main Street Bank Mobile screenshot 7 Main Street Bank Mobile screenshot 8

Similar apps & integration landscape

Main Street Bank Mobile sits inside a wider US mobile-banking ecosystem. Teams that integrate with it usually need parallel connectors for one or more of the following apps. Each entry below summarises the data that app exposes and how it relates to a unified open-banking pipeline — none of these apps are competitors in any negative sense, they are simply parts of the same landscape.

  • Bank of America Mobile Banking — Holds checking, savings, credit-card, mortgage and brokerage data; users with multi-bank households often want unified balance sweeps that cover both BoA and a community-bank app like Main Street Bank Mobile.
  • Chase Mobile — Houses checking, credit-card and Zelle transfer history; teams aggregating personal finance data typically need a Chase connector alongside any community-bank connector.
  • Wells Fargo Mobile — Carries deposit accounts, loans and bill-pay history; useful as a cross-reference when modelling FDX transaction descriptors across institutions.
  • PNC Mobile — Exposes Virtual Wallet spending categories and transfers; fintechs offering category-based budgeting often pair PNC with a community-bank feed.
  • Capital One Mobile — Provides credit-card transactions, CreditWise scores and debit-card lock controls; complements the deposit-side data Main Street Bank Mobile carries.
  • Citizens Bank Mobile — In March 2025 Citizens launched an FDX-aligned Open Banking API for consented data sharing; a useful reference point for what an FDX-conforming wrapper around a similar regional bank looks like.
  • CBNA Mobile Banking (Community Bank N.A.) — Another regional US deposit-taking institution app; same data footprint (balances, transactions, mobile deposit) as Main Street Bank Mobile, often integrated by the same finance teams.
  • CB2GO (Community Bank of Mississippi) — Southern-US regional banking app whose data model mirrors the one described on this page; relevant for ERPs that need geography-spanning coverage.
  • My MSB Mobile — A separately-listed Main Street Bank-branded app on a different mobile-banking platform; teams sometimes need both to be supported during a customer migration window.
  • MainstreetCBF Mobile — Another small-bank app on the GRIP platform; same FDX-shape integration approach applies.

For each of these apps, the same OAuth + FDX-aligned wrapper pattern works: token issuance, scoped consent, balance and transaction resources, transfer endpoints, and a deposit pipeline. That makes a Main Street Bank Mobile connector a natural starting point for a multi-app integration roadmap.

About us

OpenFinance Lab is an independent technical studio focused on App interface integration and authorised API integration. Our engineers come from banks, payment processors, mobile protocol analysis, and cloud platforms; we have shipped FDX-shaped connectors, payment-rail wrappers and statement-export pipelines for B2B and B2C teams.

  • Retail banking, lending, insurtech, and cross-border payments coverage
  • Enterprise API gateways, security reviews and audit support
  • Custom Python, Node.js and Go SDKs with test harnesses and synthetic fixtures
  • End-to-end pipeline: protocol analysis → build → validation → compliance
  • Source code delivery from $300 — runnable API source code with full documentation; pay after delivery upon satisfaction
  • Pay-per-call API billing — call our hosted API and pay only per call, no upfront cost; ideal for usage-based billing

Contact

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

Contact page

Engagement workflow

  1. Scope confirmation: list the data flows you need (balances, transactions, bill pay, transfers, mRDC) and the destination system.
  2. Protocol analysis and FDX-mapping design (2–5 business days, complexity-dependent).
  3. Build and internal validation against synthetic fixtures (3–8 business days).
  4. Documentation, Postman collection and integration tests (1–2 business days).
  5. Typical first delivery: 5–15 business days; bank-side review may extend timelines.

FAQ

What input do you need to start a Main Street Bank Mobile integration?

The target package ID (com.bankmainstreet.imobile), the specific data flows you need (balances, transactions, mobile check deposit, bill pay, transfers), an authorized test login or sandbox credentials, and the destination system (accounting platform, ledger, dashboard) where the data should land.

How long does a typical Main Street Bank Mobile API delivery take?

A first runnable drop covering login, balances and statements is typically 5 to 12 business days. Adding bill pay, transfers between institutions and mobile remote deposit capture (mRDC) ingestion adds another 5 to 10 business days depending on review by the institution.

How do you stay aligned with Section 1033 and FDX standards?

Whenever a regulated FDX-aligned channel is available we route through it and ship code that mirrors the FDX v6.x consent, accounts, transactions and payments resources. Where only the consumer mobile channel exists, we work under explicit user authorization with consent records, scoped tokens and minimised data retention.

Do you support mobile check deposit (RDC) ingestion?

Yes. We can wrap the photo-of-check submission flow as a server-side endpoint, capture front and back JPEG/PNG images, post them to the bank's RDC pipeline and surface deposit status (pending, posted, rejected) back to your accounting system or ledger.
📱 Original app overview (appendix)

Main Street Bank Mobile (package com.bankmainstreet.imobile) is the official mobile banking application from Main Street Bank, a US community-bank issuer that lets retail and small-business customers manage checking, savings and consumer-loan accounts on Android and iOS.

Per the publisher's own description, the app delivers:

  • Manage Your Accounts — Monitor checking and savings (current and available); view mortgage, auto loan and other account balances; set up Account Alerts and adjust preferences.
  • Quick Access — Touch ID and Face ID for fast and safe access; Fast Balances to peek at balances on the go.
  • Enhanced Navigation — Profile menu for notifications and personal preferences; navigation tray for top-used features; hamburger menu with the full set of transactional tools.
  • Deposit Funds — Photo-based mobile check deposit; instantly view the processing deposit in your account.
  • Make Transfers and Payments — Transfer funds between your accounts and to other financial institutions; view and manage bills and recurring payments in one place.
  • Disclosure — The mobile app is free; mobile carrier message and data rates may apply; some features are only available for eligible account holders and accounts.

The integration positioning on this page treats those screens as the raw surface area: every one of them maps to a structured data resource in an FDX-shaped API, which is how third parties move that data into accounting, treasury and analytics systems.

Last updated: 2026-05-02