PayNest API integration & SMS Transaction OpenData services

1. SMS ingestion & parser module

A reproducible parser library that recognizes credit / debit / refund / transfer patterns across banks and wallets. Used to replay PayNest's on-device logic on a server-side queue, for example when a client wants to run daily batch parsing from an encrypted SMS archive exported from the handset.

2. Account history API

REST endpoint returning PayNest-style grouped histories keyed by sender (e.g. "HDFC-BK", "MPESA", "GTB"). Supports paging, date filters, and currency filters — same shape a bookkeeping stack expects when syncing multiple accounts for a single freelancer or SME.

3. Income & expense report API

Daily, weekly, and monthly aggregates for spend, income, refunds, transfers, and unknown charges. Use case: powering a finance dashboard or pushing monthly P&L rollups into QuickBooks, Xero, or internal ERP.

4. Export & compliance bundle

Excel and CSV exports replicating PayNest's export format, plus OFX for accounting tools. Use case: year-end tax filings for freelancers in Ghana, Nigeria, India, and the Philippines who rely on mobile money as their primary rail.

5. Webhook & real-time feed

For every new parsed SMS, an optional signed webhook hits the client's endpoint with {amount, currency, direction, sender, ref_id, occurred_at}. Use case: instant expense alerts and near-real-time cash-flow monitoring for SMBs.

6. SDK & test harness

Python and Node.js SDKs with golden-sample SMS fixtures for 20+ issuers, plus a test harness that validates parser output against labelled CSVs. Use case: CI pipelines that must prove parser accuracy before each release.

Scenario A — SME cash-flow dashboard

A West African SME owner receives payments via MTN MoMo, Orange Money, and a GTBank account. PayNest already parses these SMS locally. We wrap the parsed data in an /accounts/{sender}/transactions API, push hourly rollups to the owner's BI tool, and expose /reports/monthly for accountants. OpenData mapping: equivalent to a pre-PSD2 "aggregated account information service" for rails that have no public Open Banking endpoint.

Scenario B — Freelancer tax & invoicing sync

A freelancer in the Philippines or India uses multiple wallets (GCash, Maya, UPI apps) plus one bank. We consume PayNest's sender-grouped histories, map categories to tax-relevant buckets, and deliver monthly Excel and OFX exports ready for import into QuickBooks, Zoho Books, or a BIR/GST filing workflow. Fields touched: amount, currency, direction, occurred_at, counterparty_hint.

Scenario C — Lender affordability & thin-file scoring

A digital lender in Nigeria or Kenya needs cash-flow evidence for customers without full bank statements. Under explicit user consent, our API returns 90 days of normalized transactions plus income/expense rollups. The lender's scorecard consumes monthly_inflow, volatility, and loan_servicing_signals — all derived from the same on-device SMS pipeline PayNest already uses.

Scenario D — ERP reconciliation for mobile-money acquirers

An e-commerce merchant accepts mobile money and needs to reconcile wallet credits against order IDs. Our webhook feed fires on each parsed credit SMS, passing the free-text reference; a reconciliation service matches the reference to the open order and closes it. OpenFinance framing: this is the "confirmation of payment" flow that PSD2 RTS describes, rebuilt for rails that never had it.

Scenario E — Compliance archive for regulated users

A regulated advisor (e.g. in the EU under AML obligations) wants a tamper-evident archive of a client's mobile money movements. We produce signed monthly CSV / PDF statements from the PayNest pipeline, store hashes in an append-only log, and expose /archives/{year}/{month} with access control. This aligns with GDPR Article 5 data-minimization while still giving auditors what they need.

API 1 — List transactions

POST /api/v1/paynest/transactions/list
Content-Type: application/json
Authorization: Bearer <USER_CONSENT_TOKEN>

{
  "account_sender": "MPESA",
  "from_date":     "2026-03-01",
  "to_date":       "2026-03-31",
  "direction":     ["debit","credit"],
  "currency":      "KES",
  "page":          1,
  "page_size":     50
}

// 200 OK
{
  "page": 1,
  "total": 137,
  "items": [
    {
      "id":           "tx_7f3a...",
      "occurred_at":  "2026-03-14T08:22:11Z",
      "direction":    "credit",
      "amount":       2500.00,
      "currency":     "KES",
      "sender":       "MPESA",
      "counterparty": "JOHN M.",
      "ref":          "SFA1B2C3",
      "raw_sms_hash": "sha256:..."
    }
  ]
}

API 2 — Monthly report

GET /api/v1/paynest/reports/monthly?year=2026&month=03
Authorization: Bearer <USER_CONSENT_TOKEN>

// 200 OK
{
  "period":       "2026-03",
  "currency":     "NGN",
  "income":       842000.00,
  "expense":      537210.50,
  "refunds":      12000.00,
  "transfers":    95000.00,
  "unknown":       3400.00,
  "by_account": [
    { "sender":"GTB",    "in": 500000.00, "out": 310200.00 },
    { "sender":"OPAY",   "in": 342000.00, "out": 227010.50 }
  ]
}

API 3 — Webhook event (parsed SMS)

POST https://client.example.com/hooks/paynest
X-PayNest-Signature: t=1712000000,v1=...
Content-Type: application/json

{
  "event":    "transaction.parsed",
  "tx": {
    "id":         "tx_91c2...",
    "direction":  "debit",
    "amount":     199.00,
    "currency":   "PHP",
    "sender":     "GCASH",
    "ref":        "ORD-88421",
    "occurred_at":"2026-04-19T10:41:02+08:00"
  }
}

// Expected: 2xx within 5s; otherwise retry with
// exponential backoff for up to 24h.

Error handling & auth notes

• 401 — consent token expired; redirect user to re-authorize on device.
• 409 — duplicate SMS hash; transaction already ingested.
• 422 — SMS format not recognized; queued for parser training set.
• Auth: short-lived bearer tokens derived from an on-device consent record; rotation every 24h.
• Idempotency: every write accepts an Idempotency-Key header tied to raw_sms_hash.

Deliverables checklist

• OpenAPI / Swagger specification for transactions, reports, and webhooks
• Protocol analysis report: SMS format coverage, parser rules, edge cases
• Runnable source code (Python or Node.js) for parser + API server
• Golden-sample SMS corpus and automated parser accuracy tests
• Compliance guidance: Play Store SMS policy, GDPR, DPDP, NDPA alignment
• Excel / CSV / OFX export generators matching PayNest's native format

Engagement workflow

1. Scope confirmation: target senders, countries, data types (1 day).
2. Protocol analysis and API design (2–5 business days).
3. Build and internal validation against golden samples (3–8 business days).
4. Docs, SDK samples, and test cases (1–2 business days).
5. First delivery typically 5–15 business days end-to-end.

FAQ

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About our studio

We are an independent technical services studio focused on App interface integration and authorized API work. Our engineers have multi-year hands-on experience in mobile applications, fintech, and mobile money rails across Africa, South Asia, and South-East Asia. We regularly ship protocol analysis, interface refactoring, OpenData integration, third-party API integrations, automated data scripting, and complete interface documentation for global clients.

• Financial and banking apps — transaction records, statement queries, transaction integration
• E-commerce, food delivery, and retail apps — order interfaces, payment integration, data sync
• Hotel, travel, and mobility apps — booking interfaces, itinerary queries, payment verification
• Social, OTT media, and dating apps — authentication, messaging, user profile management
• Source-code delivery from $300 — runnable API source plus documentation; pay after delivery upon satisfaction
• Pay-per-call API billing — access our hosted API endpoints with no upfront fee, usage-based pricing

Contact

Send us the target app (PayNest already confirmed) and your requirements — we'll come back with scope, timeline, and price. Both source-code delivery and pay-per-call API billing are available.

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