Integrating with Wynk Systems

One versioned HTTP API over the same domain packages the portals use. There is no second, weaker path into the core for integrations.

Credentials are issued during onboarding, per tenant and per environment. There is no public sandbox key on this page: a sandbox that anyone can reach is a sandbox that has to be defended, and we would rather give you a real one with your own tenant boundary.

Six rules that hold everywhere

Authentication is per request, and authority is never client-asserted

A caller presents a credential; the server resolves the tenant and the roles. A client cannot assert a role, a tenant, or a user id — those are derived server-side and any request that tries to supply them is refused.

Every money POST carries Idempotency-Key

A replay with the same key returns the ORIGINAL outcome marked already-processed. A replay with the same key and a different body is a conflict, not a second movement. Non-money writes accept the header and honour it the same way.

Amounts are integer minor units, always

Every amount field is named *_cents and carries an integer. There is no decimal amount and no implied scale. A currency travels with the amount; a bare number is refused.

Errors are a closed taxonomy

Every failure is one of a fixed set of wynk.* codes with a stable shape: code, message, and structured details. An integrator can exhaustively switch on the code, and a new failure mode does not invent a new string.

Reads are keyset-paginated

Collection endpoints return a cursor, not an offset. A page boundary is stable while the collection is being written to, which offset pagination cannot promise.

Webhooks are signed, ordered and replayable

Deliveries carry a signature over the canonical body, a delivery audit chain and a dead-letter queue. A consumer that was down replays from the last acknowledged delivery rather than losing the window.

The endpoints

Read surfaces are keyset-paginated. Every endpoint that moves money is marked, and every one of those requires an idempotency key.

Wynk Systems ecosystem API
Endpoint	What it does	Class	Replay protection
GET /v1/dashboard	Tenant-scoped portfolio summary	Read or configuration	—
GET /v1/loans	Loan facilities, keyset-paginated	Read or configuration	—
GET /v1/loans/:facilityId	One facility with its schedule and arrears state	Read or configuration	—
POST /v1/loans/unsecured	Originate an unsecured facility (NCA affordability enforced)	Moves money	Idempotency-Key required
POST /v1/loans/:facilityId/disburse	Disburse a facility (two-eyes)	Moves money	Idempotency-Key required
GET /v1/wallets	Wallets and balances in minor units	Read or configuration	—
GET /v1/wallets/:walletId	One wallet with its holds and pockets	Read or configuration	—
POST /v1/wallets	Open a wallet against a ledger account	Read or configuration	Idempotency-Key required
POST /v1/wallets/:walletId/deposit	Credit a wallet from a settled inbound	Moves money	Idempotency-Key required
POST /v1/wallets/:walletId/transfer	Move value between wallets	Moves money	Idempotency-Key required
GET /v1/vas	VAS catalogue and transaction history	Read or configuration	—
POST /v1/vas/purchase	Buy airtime, data, electricity or a bill payment	Moves money	Idempotency-Key required
POST /v1/payments/instruct	Instruct an outbound payment onto a rail	Moves money	Idempotency-Key required
GET /v1/ledger/facts	Accounting facts with their legs	Read or configuration	—
GET /v1/accounting/facts	Fact stream for reconciliation	Read or configuration	—
GET /v1/accounting/walk-back/:factId	Walk a fact back to its origin event	Read or configuration	—
GET /v1/accounting/legs/:legId/walk-back	Walk a statement line back to its origin	Read or configuration	—
POST /v1/accounting/chart/ensure	Ensure the chart of accounts for a tenant	Read or configuration	Idempotency-Key required
POST /v1/accounting/afs/:tenantId/generate	Generate annual financial statements for a framework	Read or configuration	Idempotency-Key required
POST /v1/chain/verify	Recompute the audit and ledger chains from origin	Read or configuration	Idempotency-Key required
POST /v1/compliance/disclose	Zero-knowledge prudential disclosure to a regulator	Read or configuration	Idempotency-Key required
GET /v1/audit	Hash-chained audit events	Read or configuration	—

What a call looks like

Originating an unsecured facility. The affordability assessment runs server-side and a breach refuses the origination — it does not warn.

POST /v1/loans/unsecured
Authorization: Bearer <tenant credential>
Idempotency-Key: 8f1c0a3e-4d2b-4a19-9f7e-2c6d1b0a5e34
Content-Type: application/json

{
  "borrower_person_id": "…",
  "principal_cents": 2500000,
  "currency": "ZAR",
  "term_months": 24,
  "purpose_code": "consolidation"
}

A replay of the same key. The original outcome comes back marked, and no second facility exists.

HTTP/1.1 200 OK
Idempotency-Status: replayed

{
  "facility_id": "…",
  "status": "originated",
  "already_processed": true
}

A refusal. Every failure is one of a closed set of codes with a stable shape.

HTTP/1.1 409 Conflict

{
  "code": "wynk.conflict",
  "message": "consumer is under debt review",
  "details": { "reason": "nca_s86_debt_review", "since": "2026-03-11" },
  "correlation_id": "…"
}

Walking a statement line back to the human decision behind it.

GET /v1/accounting/legs/<legId>/walk-back

{
  "leg": { "account_code": "1104-loans-sme", "amount_cents": -450000, "side": "C" },
  "fact": { "id": "…", "chain_seq": 918342, "hash_row": "…" },
  "origin_event": { "kind": "loan.repayment", "at": "…" },
  "workflow_step": { "id": "…", "approved_by": "…", "two_eyes": true },
  "mandate": { "kind": "debicheck", "reference": "…" }
}

The error taxonomy

Closed, so an integrator can switch exhaustively. A new failure mode maps onto an existing code or the taxonomy changes in a versioned release — it never appears as a new free-text string.

Closed error taxonomy
Code	HTTP	Meaning
wynk.validation	400	The request shape or a field value is invalid. The details name the field.
wynk.unauthenticated	401	No usable credential. Uniform for absent, malformed and expired — deliberately not an oracle.
wynk.forbidden	403	Authenticated, but the action is outside this caller's authority — including a browser-security refusal.
wynk.not_found	404	No such resource within this tenant. A resource in another tenant is not found, not forbidden.
wynk.conflict	409	A lifecycle or uniqueness precondition failed — including an idempotency key replayed with a different body.
wynk.rate_limited	429	The caller exceeded a route quota. The response carries the retry window.
wynk.upstream.unavailable	502	A required counterparty or provider is unreachable. The operation is refused, never partially applied.
wynk.internal	500	An unexpected fault. The response carries a correlation id and nothing else.

Webhooks

Every delivery is signed over the canonical body, so a consumer verifies authenticity without a shared transport secret in a query string.
Deliveries carry a sequence and a delivery audit chain — a consumer detects a gap rather than assuming completeness.
Failed deliveries retry with exponential backoff and land in a dead-letter queue that is visible in the admin portal, not in a log nobody reads.
Replay is supported from the last acknowledged delivery, so an outage on your side costs you latency, not events.

Environments

Sandbox — your own tenant, fixture data, mock counterparties. Every rail responds; none of them move real value.
Pre-production — your own tenant, your migrated data, live counterparties in their test modes.
Production — cutover happens with a chain attestation on both sides, so the opening balances you carry across are evidenced rather than asserted.

Integration questions go to developers@wynk.systems. If you are evaluating, the fastest route is a sandbox tenant — start at onboarding.

Wynk Systems is a bank-grade core-banking platform. Registered in South Africa.
This site is informational: nothing on it constitutes an offer, a quotation, or credit advice.