Wirex Pay Gen2

Abstract

Wirex Pay Gen2 replaces the “one smart-contract per asset” model of Gen1 with a single ERC-4337 Account Abstraction (AA) wallet that can own and govern any asset: cards, IBAN accounts, token balances, loyalty points, or future primitives we haven’t dreamed up yet. This article explains why moving from siloed contracts to AA delivers lower gas costs, simpler integrations, stronger security, and a seamless user experience.

Architectural Evolution

Era	Contract Topology	Key Characteristics
Gen1	Separate contract for each entity (Card SC, BankAccount SC, Reward SC…)	• Asset logic isolated<br>• High deployment/gas overhead<br>• Complex cross-contract permissions<br>• Users juggle many addresses & keys
Gen2	One AA wallet per user + modular “plugins” (card module, SEPA module, rewards module)	• Unified control plane<br>• Sign-once UX (session keys, passkeys)<br>• Shared gas pool & batching<br>• Pluggable features without redeploying core wallet

What changed?

Deterministic wallets instead of bespoke contracts – Every user is assigned an AA wallet at onboarding.
Modules ≠ full redeploys – Need a new feature? Deploy a lightweight module and plug-in; the root wallet stays intact.
Delegate-call pattern – Modules execute within the wallet’s context, inheriting its balance & permissions.

Why Account Abstraction?

1. Unified Security Boundary

A single wallet means a single signing scheme, a single nonce space, and a single recovery flow. Attack surface shrinks dramatically compared with multiple scattered contracts where each must implement its own access control.

2. Lower Gas & Better UX

Batching – AA lets you bundle card-top-up + on-chain payment + SEPA sweep in one transaction.
Session keys – Mobile apps can issue ephemeral keys for high-frequency spend without exposing the master key.
Pay-master support – Partners can sponsor gas so end users pay zero network fees.

3. Future-Proof Modularity

Need Apple Pay tokenisation, multi-sig for VIPs, or a new CBDC rail? Drop-in a module—no need to rewrite the wallet or migrate balances.

4. Simplified Compliance & Audit

All actions route through one wallet address, producing a clean, chronological audit trail that is easier for regulators (and your finance team) to verify.

5. Reduced Friction for Users and Partners

Stakeholder	Benefit	Explanation
Users	Fewer approval prompts	Sign once per session instead of approving each contract separately.
	Unified interface	One smart wallet controls all assets, reducing complexity and cognitive load.
	Better mobile experience	Session keys and gas sponsorship reduce clicks and confirmations in mobile flows.
Partners	Less code to maintain	No need to deploy or audit new contracts for every asset type or feature.
	Faster integration	Plug-and-play modules simplify backend logic and reduce the API/testing footprint.
	Lower onboarding cost	Shared infrastructure and simplified wallet logic accelerate MVP delivery.

In short, Gen2 minimizes onboarding, operational, and support costs while offering a more cohesive user experience across wallet-connected products.