Testing a National Payment Switch Across Four Card Schemes

How 1LINK — Pakistan's largest payment switch — uses neaPay to test Visa, MasterCard, UnionPay, and JCB interfaces from a single simulator

4

Card schemes tested

11+

Member banks supported

1

Simulator for all protocols

Years

Ongoing collaboration

About 1LINK

1LINK is Pakistan's first fully licensed PSO/PSP and the country's largest payment and switch system. Owned by a consortium of 11 member banks, 1LINK operates the Inter-Bank Network providing ATM interoperability, real-time inter-bank funds transfers, and connectivity to global card schemes including Visa, MasterCard, UnionPay International, and JCB.

As a national infrastructure provider, 1LINK is responsible for both its own interface certification with card schemes and for enabling member banks to onboard and test against the switch. Every protocol change, every new member bank, every scheme certification window requires rigorous, repeatable testing across all connected interfaces simultaneously.

The Challenge

A national switch connecting to Visa, MasterCard, UnionPay, and JCB cannot rely on separate, protocol-specific simulators. The coordination overhead alone — maintaining four different toolchains, four configuration sets, four regression packs — creates fragility and slows down every certification and upgrade cycle.

Beyond scheme connectivity, 1LINK also needs to certify and onboard member banks against the switch's own ISO8583 interfaces — a repeating process for each new member.

Multiple card scheme interfaces to test simultaneously
Member bank onboarding requires switch-side simulation
Regression packs must cover all protocols after any code change
EMV, PIN and cryptographic validation at national-switch scale
Performance testing — the switch must handle national transaction volumes

The neaPay Solution

neaPay provided its ISO8583 Payments Simulator — purpose-built to handle multiple card scheme interfaces from a single installation, with all protocol configurations version-controlled and portable across environments.

Single simulator for all four schemes — Visa, MasterCard, UnionPay, JCB pre-configured
Acquirer and issuer simulation — test the switch from both sides of the transaction
Full EMV support — PIN block, MAC, ARQC/ARPC, issuer script generation
Functional, regression and performance testing — all from one tool
1000 TPS load testing — validated against national processing volumes
Version-controlled configuration — same test conditions reproducible across all environments
New protocols added incrementally — no re-architecture required

The Outcome

After deploying neaPay's simulator, 1LINK was able to consolidate its testing infrastructure and run scheme certifications and regression cycles significantly faster than before.

One simulator environment for all four card schemes — maintenance reduced to a single tool
Scheme deliverables ready before certification windows open — no delays waiting on neaPay side
New member banks onboarded against the switch using the same simulation framework
Regression pack grows each year — more endpoints, more protocols, more coverage
Performance testing baseline established and reused for each release
Long-term collaboration: new protocols and interfaces added over the years without replacing the core tooling

"neaPay is so fast with deliverables we need to wait for the scheme to give us access or check tests — neaPay is already in place."

Product Manager, National Card Processing Center

Why a National Switch Needs an Enterprise Simulator

The difference between free ISO8583 tools and neaPay at national-switch scale

Multi-scheme from one instance

Free tools simulate one protocol. 1LINK needs Visa, MasterCard, UnionPay, and JCB tested simultaneously. neaPay handles all four from the same installation, with independent configuration per scheme.

EMV at scheme certification depth

Scheme certification requires full EMV validation — PIN blocks, MAC generation and verification, ARQC/ARPC, issuer scripts, key session management. Free tools do not cover this.

1000 TPS performance validation

A national switch must prove its throughput ceiling before go-live and after every major release. neaPay's simulator is the tool that generates and sustains the load needed to produce that proof.

Version-controlled test environments

Test configs delivered via Git ensure that the conditions used for certification are identical to those used in regression — and reproducible a year later when the same scheme re-certifies.

Member bank onboarding

When a new member bank joins the switch, the switch-side simulator is already configured. The new bank tests against the existing simulation environment — no new tooling, no new setup.

Long-term, protocol-agnostic

New card schemes and interfaces are added to the existing neaPay installation as the switch expands. No replacement cycle. The simulator grows with the infrastructure.

Similar profiles that use neaPay

neaPay works with national switches, regional processors, and large card issuers across four continents. If your organisation connects to more than one card scheme, certifies member institutions, or needs to prove throughput at national scale, the conversation starts with a free POC.