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Payment Infrastructure

E-Wallet Platform

Balances, P2P and stored value

Presentation

Overview

An e-wallet platform gives your users a persistent balance they can fund, spend, transfer and withdraw, backed by a ledger that a regulator, auditor or your own finance team can trust completely. Pay Engineers builds wallet platforms for fintechs, banks, marketplaces and embedded finance providers who need stored value as a core product feature rather than a side effect of another system.

The engineering challenge in wallet platforms is rarely the user-facing transfer screen. It is the ledger underneath it: every top-up, transfer, fee, refund and withdrawal must be represented as a correctly balanced double-entry movement so that at any moment the sum of user balances reconciles exactly against the funds actually held. We build that ledger first and the product experience around it, not the other way round.

Wallets are also inherently regulated products in most jurisdictions, so the platform is designed from the outset with the KYC tiers, limits and reporting hooks that safeguarding, e-money and payment institution regimes expect.

Who This Is For

  • Fintechs and digital banks launching consumer or business wallet products
  • Marketplaces and gig-economy platforms that need to hold and move balances on behalf of users before withdrawal
  • Embedded finance providers adding stored value to a non-financial application
  • Businesses operating under an EMI or PI licence, or partnering with one, that need a compliant ledger and limit framework

What You Get

  • A multi-currency ledger built on double-entry accounting principles, giving you a provably balanced record of every fund movement
  • Peer-to-peer and person-to-merchant transfer flows with configurable fees and settlement timing
  • Limits and velocity rules tied to KYC tiers, so lightly verified users have restricted exposure while fully verified users unlock higher thresholds
  • Mobile SDK hooks so your iOS and Android apps can integrate wallet balances, transfers and history natively

Technical Approach

The core ledger and transfer logic is built in Go for predictable performance under concurrent balance updates, with Laravel handling API orchestration, onboarding and administrative tooling. PostgreSQL stores the ledger as an append-only, double-entry structure, so historical balances can always be recomputed and audited rather than trusted blindly from a mutable balance field. Redis supports velocity checks and short-lived transfer locks to prevent race conditions on simultaneous balance movements.

KYC tiers are modelled as first-class entities that drive limits, available features and reporting obligations, rather than a single flag on the user record. This makes it straightforward to tighten or loosen thresholds as regulatory guidance or your own risk appetite changes. Where card top-ups or withdrawals are required, the wallet integrates with your chosen issuing or acquiring partner through well-defined connectors rather than tight coupling, so that partner can be changed later without a ledger redesign.

Delivery Process

We approach wallet builds with particular rigour around the ledger design, since it underpins every other feature:

  • Discovery covering your regulatory basis, KYC tiering strategy, currencies and expected transaction patterns
  • Ledger and data model design, reviewed explicitly for double-entry correctness and reconciliation properties
  • Sprint-based build of core wallet operations, followed by transfer, limits and mobile SDK layers
  • Load and consistency testing focused on concurrent balance updates and edge cases such as partial failures
  • Phased rollout starting with a controlled user cohort before opening to full production traffic

Outcomes and Benefits

  • A ledger your finance and compliance teams can trust and reconcile without manual intervention
  • A wallet product that can scale from thousands to millions of users without a ledger rewrite
  • Regulatory-ready limit and tiering structures that adapt as your KYC policy evolves
  • Mobile-ready APIs that let your product team ship wallet features without waiting on backend rework

Technologies

Laravel Go PostgreSQL Redis Mobile SDK

FAQ

Every balance movement, top-up, transfer, fee and withdrawal is recorded as a correctly balanced double-entry ledger transaction, so at any point in time the sum of user balances can be reconciled exactly against the funds held in your safeguarding or settlement accounts. We build the ledger core before any user-facing feature, and every product feature is required to express its financial effect through that ledger rather than adjusting balances directly. This gives your finance and compliance teams a single source of truth that stands up to internal audit and regulatory inspection. Reconciliation reports comparing ledger balances to bank account statements are generated automatically rather than assembled manually.
The platform supports tiered KYC, so users can start with lighter verification for low balance and transaction limits and progress to full identity verification as their usage grows, which is the model most regulators expect for consumer wallet products. We integrate your chosen identity verification and AML screening vendors rather than building identity checks from scratch, and the tier and limit configuration is managed centrally so compliance can adjust thresholds without a code deployment. Limit enforcement happens at the transaction layer, so a user cannot exceed their tier's spending or holding limits regardless of which client application they use. This structure is designed to align with typical e-money and payment services regulatory expectations across most jurisdictions.
Yes, peer-to-peer and person-to-merchant transfers within the platform are supported as instant ledger movements, and we integrate external payout rails such as bank transfer or card push-to-wallet for funding and withdrawal to and from outside the platform. Transfer limits, velocity checks and fraud rules are applied consistently regardless of whether the transfer is internal or external, since internal transfers are just as capable of being abused for money laundering as external ones. We configure fee logic for each transfer type separately, since many wallet businesses price internal and external movement differently. All transfer types are represented in the same ledger, so reporting does not need to reconcile across separate systems.
Operating a wallet with user-held balances typically requires an e-money or payment institution licence, or a partnership with a licensed provider under an agency or distributor model, depending on your jurisdiction and business model. We build the platform to be licence-agnostic at the technical layer, but we work closely with your legal and compliance advisors so safeguarding account structures, reporting obligations and audit trail requirements are reflected accurately in the ledger and reporting design. If you do not yet hold a licence, we can also support the technical sections of an EMI or PI application as part of a separate licensing engagement. The platform architecture does not assume a specific regulatory outcome, so it can adapt as your licensing strategy evolves.
A first production release covering wallet funding, balance holding, internal transfers and basic withdrawal typically takes 4 to 6 months, with card top-up rails, advanced tiering or embedded finance features layered in subsequent phases. The ledger core and KYC tiering are built first since every later feature depends on them, followed by the user-facing funding and transfer flows. We plan around your target launch jurisdiction's regulatory review timeline where relevant, so the technical build and licensing or partnership process can run in parallel rather than sequentially. Mobile SDKs and card top-up integrations typically extend timeline by four to six weeks depending on provider requirements.
Post-launch support covers monitoring of ledger integrity, transaction throughput and fraud rule performance, plus rapid response to any discrepancies flagged by your finance team during daily reconciliation. We provide a defined support window immediately after go-live and offer an ongoing managed evolution retainer for feature growth, new payment rail integrations and scaling work as your user base grows. Ledger and ledger-adjacent code receives particular attention in ongoing support because errors there have direct financial and regulatory consequences. You retain full access to ledger data and audit logs at all times, independent of the support arrangement in place.

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