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Self-custodial walletPayment processingPrivacy vaultRecurring billing

One stack: a wallet that's also a PSP, a vault, and a subscription engine.

Wallet, payment acceptance, confidential storage and recurring billing — one owned, non-custodial stack instead of four vendors.

Wallet · PSP · Vault · Subscriptions · A fintech building a self-custodial super-app · under NDA
In plain terms

Most consumer fintechs rent four different vendors — one for the wallet, one to process payments, one to store balances, one for subscriptions — and each quietly holds the keys. Here all four are one stack the business owns, and the user keeps their own keys throughout. No vendor sits in the middle of the money.

By the numbers
  • Wallet 25%
  • PSP rail 25%
  • Privacy vault 25%
  • Subscriptions 25%
Four rented vendors become one owned stack — four primitives, one codebase.
The challenge

They wanted to own the whole consumer stack — wallet, acceptance, confidential storage and subscriptions — instead of stitching four vendors who each hold a piece, and the keys.

4-in-1
wallet · PSP · vault · billing
0
vendor lock-in
Self-custodial
end to end
What we built
  • 01A self-custodial wallet: keys on the user's device, recovery paths defined
  • 02A PSP rail: authorize, capture and settle, in contracts they own
  • 03A privacy vault for confidential balances and statements
  • 04Recurring on-chain billing with revocable, inspectable authorizations
Outcome

Every layer is theirs and non-custodial — the user holds the keys, the business holds the contracts, and no vendor sits in the middle of any of it.

How it’s wired

The architecture, end to end.

Each box is a primitive we wrote and you own — legible all the way down, no black-box vendor in the path. Value flows left to right.

1Self-custodial wallet

Keys on the user's device; recovery paths defined, not a vendor's vault.

2PSP rail

Authorize, capture and settle in contracts the business owns.

3Privacy vault

Confidential balances and statements, readable only by the owner.

4Subscription engine

Recurring billing with revocable, inspectable on-chain authorizations.

Before / after
Four vendors · four lock-ins
One owned, non-custodial stack
How we build it
  • On-chain where enforcement matters; in your infrastructure where operation matters.
  • Non-custodial by default — keys and funds stay with their owner.
  • Audited line by line, then handed over: repository, runbook, and proofs.
The difference, point by point

Legacy vs the system we built.

The legacy wayWith Govart
WalletCustodial, vendor-heldSelf-custodial, user-held
PaymentsThird-party PSPOwned contracts
VendorsFour, four lock-insOne owned stack
CustodyVendors hold the keysThe user holds the keys
The stack we built

Primitives, not black boxes.

Each layer is code you own and can read — written in-house, audited, and handed over. No rented dependency in the path of your money.

01

Self-custodial wallet

Keys on the user's device, with defined recovery paths.

02

Owned PSP rail

Authorize, capture and settle inside contracts the business owns.

03

Privacy vault & billing

Confidential balances and revocable, inspectable recurring authorizations.

What we hardened

Built as if it’ll be attacked.

In crypto, one mistake is terminal. We threat-model before we build — here’s what could go wrong, and what stops it.

The risk

A vendor in the middle quietly holds the keys.

How we guard it

Self-custodial throughout — the user holds the keys.

The risk

A vendor fails and forces a re-platform.

How we guard it

One owned stack instead of four separate lock-ins.

The risk

A runaway subscription keeps charging.

How we guard it

Authorizations are inspectable and revocable on-chain.

Handover

Yours at the end. All of it.

The engagement ends — that’s the point. What stays is everything you need to run and extend the system without us.

The repository

Every contract and service, commented and documented — nothing withheld, no black box.

Audit reports

Internal review plus an independent third-party audit, your engineers reading along.

The runbook

How to operate, monitor, upgrade and recover — written for your team, not ours.

Keys & training

Full control transferred, and your engineers walked through it until it's theirs.

Four vendors became one stack we actually own.
A fintech building a self-custodial super-app, anonymized

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Disclaimer

Govart provides software engineering, technical advisory, and infrastructure services only. We advise on technology — not on financial, investment, legal, tax, or accounting matters. Nothing on this site is advice, an offer, a solicitation, or a recommendation.

We are not a bank, broker, custodian, exchange, payment processor, money-services business, or virtual-asset service provider, and we never hold, transmit, or take custody of client or end-user funds.

KYC, AML, sanctions screening, licensing, and regulatory compliance remain the responsibility of the operator that owns and runs each deployed system. We build the controls you specify; we do not act as your compliance function. Figures and examples shown are illustrative only.

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