A2A Banking

Transfer lifecycle simulator

Step through exactly what the MerasPay A2A engine does for each scenario — sanctions checks, liquidity gates, 4-eyes approval, duplicate detection, and post-settlement returns. Fully client-side: no credentials required, no real money moves.

Seven scenarios covered

✓

Happy path — settles in <100 ms

All checks pass. Ledger posts atomically; Bank B notified via webhook.

✗

AM04 — insufficient liquidity

Creditor bank's nostro is below the transfer amount. Rejected upfront; rebalance queued.

⏸

Sanctions hit → ACWP hold

AML screen matches creditor name. Transfer held; compliance reviews; released or rejected.

⏸

High value → 4-eyes approval

Amount exceeds threshold. Auto-routed to a second admin before any ledger posting.

↺

Duplicate UETR — idempotent replay

Retry arrives with the same UETR. Original pacs.002 replayed; no double-charge.

✗

AC01 — incorrect account

Creditor account fails pre-validation at the creditor bank. Rejected before any ledger entry.

↩

Post-settlement return (pacs.004)

Bank A initiates a return after settlement. Inverse ledger legs restore both nostros.

Interactive simulator

Select a scenario from the dropdown, then hit Play to auto-step through the timeline, or use Step to advance one event at a time. The pacs.008 envelope on the left reflects the request payload; the timeline on the right shows each engine decision with timing.

Interactive simulator

Step through real lifecycle events. Pure simulation — no API calls, no real money. Pick a scenario, then play or step.

Customer at Bank A pays a customer at Bank B. Sanctions clear; liquidity is sufficient; amount under approval threshold.

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What the bank apps show

Mock UIs that mirror your customers' experience in real time.

9:41●●● ▮

Bank A

Sender

Saba mobile

Alice Mohamed

New transfer

Amount

50,000 DJF

Bob Hassan

EAB-0001234567

At bank

EABKDJJDXXX

Confirm

Routed via Meras A2A

● SendHistoryAccountsMore

9:41●●● ▮

Bank B

Receiver

EAB online

Bob Hassan

💤

App in background

● SendHistoryAccountsMore

pacs.008 (JSON envelope)

{
  "type": "pacs.008.001.08",
  "msg_id": "BANKA-2026-05-24-000123",
  "settlement": {
    "method": "CLRG",
    "clearing_system": "MERAS"
  },
  "transactions": [
    {
      "uetr": "11111111-2222-3333-4444-555555555555",
      "end_to_end_id": "ORD-42",
      "amount_minor": 50000,
      "currency": "DJF",
      "debtor": {
        "name": "Alice Mohamed",
        "account": "DJ81000010000000000000123"
      },
      "debtor_agent": "BSABDJJDXXX",
      "creditor": {
        "name": "Bob Hassan",
        "account": "EAB-0001234567"
      },
      "creditor_agent": "EABKDJJDXXX",
      "charge_bearer": "SLEV"
    }
  ]
}

Final outcome

succeededACSC

Nostro impact

bnk_BSAB+50,000 DJF

bnk_EAB-50,000 DJF

Timeline

0msBank A
POST /banking/v1/transfers
5msMerasPay
mTLS cert fingerprint matched → bnk_xyz
6msMerasPay
JWS signature verified
10msMerasPay
Idempotency — UETR not seen before
12msMerasPay
Creditor bank EABKDJJDXXX resolved + active
14msMerasPay
Per-tx cap OK
18msMerasPay
Creditor nostro liquidity sufficient
22msMerasPay
AML — debtor clean
23msMerasPay
AML — creditor clean
26msMerasPay
Below approval threshold
30msMerasPay
Ledger: DR nostro_at_A 50,000 / CR nostro_at_B 50,000
38msMerasPay
HTTP 200 — pacs.002 ACSC
45msMerasPay
Webhook a2a.transfer.succeeded dispatched
50msBank B
Bank B credits Bob's account

ℹ

Reading the timeline

Each row shows the actor (Bank A, MerasPay, Bank B, Admin / Compliance), the event label, an optional detail string (e.g. the actual nostro balance at decision time), and whether the step succeeded (green) or failed/held (red / amber). Steps not yet reached are dimmed.

Status codes you will see

Code	Meaning	HTTP	Scenarios
ACSC	Accepted — settlement completed	200	Happy path, duplicate replay
ACWP	Accepted without posting — pending review	202	Sanctions, high value
RJCT	Rejected	200	AM04, AC01, return
AM04	Insufficient nostro liquidity	200	Liquidity scenario
AC01	Incorrect account number	200	Bad account scenario
FF08	Invalid end-to-end ID (sanctions hold)	202	Sanctions scenario

Next steps

Guide

Sandbox environment→

Test credentials, deterministic scenario keys, and BICs for connecting your real systems.

Reference

Bank onboarding→

Conformance suite, mTLS cert provisioning, nostro funding, and go-live sign-off.

Reference

Message reference→

Full pacs.008, pacs.002, pacs.004, camt.056 schema with required/optional annotations.

Guide

Error codes→

Complete ISO 20022 reason code list with MerasPay-specific extensions.