TAP Wallet API integration (multi-chain & OpenFinance)

Deliverables checklist

• OpenAPI 3.1 specification for every endpoint we expose
• Protocol and authentication report (token lifecycle, refresh, error codes)
• Runnable source for login, balance, transaction and send-payment APIs in Python and Node.js
• Integration test harness with deterministic fixtures per chain
• Compliance pack: KYC fields, Travel Rule message template, retention notes

Two engagement models

• Source-code delivery from $300 — full repository handover; pay after delivery upon satisfaction.
• Pay-per-call hosted API — call our endpoints and pay only for the requests you make; ideal for proofs-of-concept and seasonal traffic.
• Hybrid — start hosted, migrate to self-hosted later using the same OpenAPI contract.

1 · Treasury reconciliation across chains

Business context: a fintech holds operating balances in TAP Wallet across BTC, USDC on Solana, and USDT on Polygon. The accounting team needs a single ledger view. We pull balances and transaction history per chain, normalise them into one event schema (chain, asset, direction, amount, fiat_value) and post into the customer's NetSuite/Xero pipeline. Maps to the OpenFinance "account information" primitive.

2 · Cross-border stablecoin payout

A marketplace pays creators in USDC. We expose a POST /payout endpoint that accepts recipient_address, chain, amount_usdc and returns a payment intent with idempotency key, fee preview and webhook callback on settlement. The flow inherits TAP Wallet's authentication so the payer keeps custody.

3 · Tap-to-pay merchant checkout

An in-store POS calls our create_intent endpoint with order ID and amount; the customer authenticates in TAP Wallet and the POS receives a confirmation webhook. The intent ID becomes the merchant's reference for refunds and chargeback queries — directly inspired by the patented HUMBL "transferring currency using blockchain" model.

4 · Tax and audit export

An accountant connects once and pulls a year of transactions across every linked chain into a CSV with cost basis, realised gains and stablecoin flows separated. We emit the same data as JSON for downstream tax engines (e.g. Koinly-style ingestion). Maps to OpenData "statement export".

5 · Risk and Travel Rule packaging

For VASP customers, every outbound transfer above a configurable threshold is wrapped with the originator/beneficiary payload required by the FATF Travel Rule and pushed to the customer's preferred messaging network (e.g. TRP, Notabene, Sumsub). Wallet UX is unchanged; the compliance hop is server-side.

Login & session bootstrap

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

{
  "user_ref": "merchant-9f3c",
  "device_id": "ios-3a91...",
  "scope": ["balances", "tx_history", "send"]
}

200 OK
{
  "access_token": "eyJhbGciOi...",
  "refresh_token": "rt_8f...",
  "expires_in": 3600,
  "wallet_id": "tap_2e1d...",
  "addresses": [
    {"chain":"bitcoin","address":"bc1q..."},
    {"chain":"ethereum","address":"0xab..."},
    {"chain":"solana","address":"7Yx..."}
  ]
}

Multi-chain transaction statement

GET /api/v1/tap/statement
?wallet_id=tap_2e1d...
&chain=ethereum,solana,bitcoin
&asset=USDC,USDT,BTC,ETH,SOL
&from=2026-01-01&to=2026-04-30
&page_size=200
Authorization: Bearer <ACCESS_TOKEN>

200 OK
{
  "items": [
    {
      "tx_hash": "0x4f2a...",
      "chain": "ethereum",
      "asset": "USDC",
      "direction": "out",
      "amount": "250.00",
      "fee_native": "0.00038",
      "counterparty": "0x77c3...",
      "status": "confirmed",
      "block_time": "2026-04-21T08:14:11Z"
    }
  ],
  "next_cursor": "c_19f3..."
}

Send stablecoin + webhook

POST /api/v1/tap/send
Idempotency-Key: payout-2026-04-28-001
Authorization: Bearer <ACCESS_TOKEN>

{
  "chain": "solana",
  "asset": "USDC",
  "to": "7Yx9Aj...",
  "amount": "120.00",
  "memo": "creator-payout-77",
  "travel_rule": {
    "originator_name": "Acme Marketplace",
    "originator_vasp": "did:vasp:acme",
    "beneficiary_name": "Jamie L."
  }
}

202 Accepted
{ "intent_id": "in_8a...", "status": "submitted" }

// Webhook (later)
POST /your/webhook
{ "intent_id":"in_8a...", "status":"confirmed",
  "tx_hash":"5h2k...", "fee":"0.000005" }

Regulatory alignment

For EU-facing customers we package data and message flows that fit the Markets in Crypto-Assets Regulation (MiCA) and the EU Transfer of Funds Regulation, which has enforced the zero-threshold Travel Rule since 30 December 2024. For US flows we map to the FinCEN Bank Secrecy Act expectations (MSB registration, AML programme, SARs). Stablecoin handling follows current FATF Recommendation 16 guidance.

Privacy & data minimisation

Endpoints accept scope tokens so a treasury integration cannot accidentally request KYC fields, and a fraud integration cannot read a private key. PII fields are tagged in the OpenAPI spec and the delivery includes retention guidance aligned to GDPR / UK GDPR. We never persist seed phrases, and we document exactly which fields cross network boundaries.

About us

OpenFinance Lab is an independent technical studio focused on mobile-app protocol analysis and OpenData / OpenFinance / OpenBanking integration. Our engineers come from payments, digital banks, blockchain infrastructure and mobile reverse-engineering teams.

• Specialists in fintech, crypto wallets, e-commerce, OTT and travel verticals
• End-to-end pipeline: protocol analysis → API design → build → validation → compliance
• Custom Python / Node.js / Go SDKs and test harnesses; OpenAPI as a first-class artefact
• Source-code delivery from $300, with pay-after-delivery and pay-per-call options
• Regional experience covering the US, EU, UK, Singapore and the UAE

Contact

For a quote or to brief us on a TAP Wallet (or related) integration, use our contact page.

Contact page

We respond to most enquiries within one business day and will share a written scope before any commitment.

Engagement workflow

1. Scope confirmation: chains, assets, endpoints (login, balances, statements, send, webhooks).
2. Protocol analysis & OpenAPI design (2–5 business days, scope-dependent).
3. Build and internal validation against test fixtures (3–8 business days).
4. Documentation, sample code, and end-to-end test cases (1–2 business days).
5. Typical first delivery: 5–15 business days; Travel Rule and multi-chain reconciliation may extend this.

FAQ

Which chains and assets can you integrate?

How long does a first integration take?

How do you handle compliance and the FATF Travel Rule?

Do you support self-hosted endpoints, or only your hosted API?