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Blockchain & DeFi Infrastructure for Fintechs

In short

DeFi infrastructure for fintechs is the backend a fintech or neobank uses to offer on-chain products, embedded yield, crypto-backed lending, and own-brand vaults, under its own brand: the audited protocol integrations plus the ledger, reconciliation, custody, and compliance plumbing around them.

Luis Medeiros

Reviewed by Luis Medeiros, Field CTO at ProtofireLast reviewed: October 2026

250+
projects shipped since 2016
$730M
Balancer governance TVL, up from $120M
$2B+
in assets secured through Safe across 120+ EVM networks
1M+
developers use Solhint, our Solidity linter
Trusted by teams building on-chain

Fintechs and neobanks increasingly want to offer on-chain products, yield on idle balances, loans against crypto, a branded stablecoin vault, but building them means a crypto engineering team they do not have and cannot hire quickly. Blockchain and DeFi infrastructure for fintechs is the backend that closes that gap: the audited protocol integrations that generate the yield or the loan, plus the boring-but-critical plumbing around them, ledger, reconciliation, fiat rails, custody, and compliance hooks, wired into the fintech's existing product.

Protofire builds that backend. We are an engineering-led firm with 250+ projects shipped since 2016, and we have built the DeFi primitives this depends on, so a fintech can put an on-chain product in front of its customers under its own brand without becoming a crypto company first.

The DeFi-backend stack behind a fintech's on-chain product

A customer-facing on-chain product needs a protocol half and a plumbing half; we build both.

01

Customer-facing product

The fintech's own app and brand: an earn account, a loan, or a vault, with the on-chain machinery hidden behind the UX.
02

Yield, lending & vault engine

Audited, hardened protocol integrations (Aave, Morpho, ERC-4626 vaults) that generate the yield or issue the loan, tuned to the product.
03

Stablecoin & settlement layer

The stable token the product runs on, native issuance or a third-party coin, with on/off-ramp integration.
04

Oracle & pricing

Chainlink price feeds and Proof-of-Reserve so collateral and yield are priced and proven, not asserted.
05

Custody & treasury controls

Safe multisig signing policies and treasury rules a risk committee can approve.
06

Compliance & KYC hooks

KYC, AML, and eligibility rules wired into the fintech's existing compliance stack, inside its regulatory perimeter.
07

Ledger reconciliation & reporting

Every on-chain position mapped back to the fintech's core ledger and surfaced for reporting, indexed via The Graph.
01

Who this is for: fintechs, neobanks, and B2B2C platforms

We build for fintechs and neobanks that want to add an on-chain product without becoming a crypto company. A neobank or consumer fintech adding an earn account that pays yield on idle balances. A fintech or broker with crypto custody offering loans against a customer's held crypto.

A wealth or B2B2C platform launching its own branded yield vault with its own fee and distribution. And a fintech that wants a stablecoin or on-chain settlement feature inside its app. The common gap is the same: the product idea is clear, but the backend is a crypto engineering project the team cannot staff. We qualify on whether the product is real and what the fintech can already cover in-house before we scope the build.

02

The problem: the backend is more plumbing than protocol

The hard part of a fintech DeFi product is not the smart contract, it is everything around it. The backend a fintech actually needs is roughly 40% protocol work, the yield strategy or the lending market, and about 60% boring-but-critical fintech plumbing: a ledger that reconciles on-chain positions against the core system, fiat on and off ramps, custody controls a risk committee will approve, and compliance hooks inside the regulatory perimeter.

Few crypto shops have both halves, and few fintechs have either. A pilot that sends one test transaction is easy; a production product that an auditor, a risk committee, and a regulator will accept is the part that stalls. That combination, audited protocol engineering plus the reconciliation, custody, and compliance plumbing, is exactly what we build, and it is why a fintech does not have to choose between a crypto pilot that never ships and hiring a team it cannot find.

03

What we build for fintechs

We build the on-chain product and the plumbing around it. For an earn account, we build yield-bearing stablecoin and vault infrastructure that routes idle balances into audited yield, under the fintech's brand. For lending, we build white-label lending on a hardened Aave base, including loans against held crypto.

For a branded vault, we build tokenized vault infrastructure the fintech owns and curates. Where a fintech wants its own dollar, we build native stablecoin issuance, and where it wants cross-border settlement, stablecoin cross-border payments.

For a euro account that lives in the customer's own wallet, we build wallet-linked IBAN accounts on a licensed issuer's rail. Under all of it sit the primitives, oracle integration and Proof of Reserve for pricing and reserve transparency, and once a product is live, managed on-chain operations keeps it watched 24/7.

You stay the regulated brand your customers see; we build the backend. To let AI agents pay inside your product, or charge agents for an API, agentic payment integration adds agent wallets with enforced spending limits and stablecoin settlement.

05

An engineering-led partner that has built the DeFi backend

Protofire is an engineering-led blockchain development firm with 250+ projects shipped since 2016, across 60+ networks and 95+ protocols. The credentials that matter for a fintech backend are specific. We built the governance analytics behind MakerDAO's DAI (MakerDAO is now Sky, whose USDS and DAI together form the largest crypto-collateralized dollar), and our ve8020 Launchpad carried Balancer's governance-aligned TVL from $120M to $730M at its peak, so the yield and lending machinery a fintech product sits on is a system we have built and operated.

We maintain Solhint, the Solidity linter used by 1M+ developers, and harden every contract before it reaches an external auditor. We deployed Safe, the custody layer a risk committee approves, on 120+ EVM networks, where it secures $2B+, and we are a core contributor to Chainlink, the oracle and Proof-of-Reserve layer that prices collateral and proves reserves. The protocol half and the custody-and-data half of a fintech backend are both work we have shipped at scale.

“The customer sees the fintech's brand; behind it sits an audited lending or yield protocol, a reconciled ledger, custody under Safe, and compliance hooks, engineered as one product rather than a crypto pilot bolted onto a banking app.”

DeFi engineering at protocol scale
$730Mgovernance TVL, grown from $120M on infrastructure we built

We built and operated the governance and incentive infrastructure behind Balancer, growing governance TVL from $120M to $730M, the same yield-and-incentive machinery a fintech earn or vault product sits on.

BalancerView project →

FAQ

How does a fintech add a DeFi or crypto product without a crypto team?
By building the backend with a partner and keeping the front. Protofire builds the audited protocol integration that generates the yield or issues the loan, plus the ledger reconciliation, custody, fiat-rail, and compliance plumbing around it, and wires it into the fintech's existing product. The fintech keeps its brand, its customers, its license, and its pricing; the on-chain machinery runs behind the UX. This lets a fintech ship an earn account, a crypto-backed loan, or a branded vault without hiring a crypto engineering organization it cannot staff quickly, and without a pilot that stalls on the plumbing.
What on-chain products can a fintech offer?
The common ones are an earn account that pays yield on idle or stablecoin balances, a loan against a customer's held crypto, a branded yield vault the fintech curates, a native or white-label stablecoin, and cross-border settlement on stablecoin rails. Each is the fintech's product under its own brand, built on audited protocols such as Aave, Morpho, and ERC-4626 vaults, with the yield strategy, custody, reconciliation, and compliance engineered around it. We scope which product fits the fintech's customers and regulatory reality before building.
Who holds custody and stays responsible for compliance?
The fintech does. It remains the regulated brand of record and owns the customer relationship, the compliance perimeter, and the pricing. We build KYC, AML, and eligibility hooks into the fintech's existing compliance stack rather than replacing it, and custody runs through Safe multisig under rules the fintech's risk committee approves. Protofire is the engineering and operations partner, not a custodian, an issuer, or a lender of record, and we do not hold customer funds.
Build the DeFi backend in-house or partner?
It depends on whether on-chain products are your core business or a capability you need to ship. The backend is roughly 40% protocol engineering and 60% ledger, reconciliation, custody, and compliance plumbing, drawn from talent that is scarce and slow to hire. Building in-house means standing up that whole competence before the first product ships. Partnering means the product is built on audited protocols and the plumbing is handled, with the option to insource later once scale justifies it. We scope both openly, and we harden every contract before external audit either way.
How much of a fintech DeFi backend is actually smart-contract work?
Roughly 40 percent. In our experience the backend a fintech needs is about 40 percent protocol engineering, the yield strategy or the lending market itself, and about 60 percent boring-but-critical fintech plumbing: a ledger that reconciles on-chain positions against the core system, fiat on and off ramps, custody controls a risk committee will approve, compliance hooks inside the regulatory perimeter, and monitoring. Most crypto shops build only the 40 percent and leave the 60 percent to the fintech, which is where pilots stall. We build both halves, which is what turns a demo into a production product.
How do you handle liquidation risk in a crypto-backed loan product?
The same way the largest lending protocols do, tuned per product. Loans are over-collateralized, with conservative loan-to-value and liquidation thresholds set per collateral asset, and positions are liquidated automatically when they fall below the threshold, against a stability or insurance buffer so the system stays solvent under volatility. The mechanics run on a forked, hardened Aave base, the same over-collateralized, oracle-priced liquidation model behind Aave and Compound, with Chainlink price feeds for manipulation-resistant valuation. We set the thresholds conservatively for the asset class and harden the contracts before external audit, and the fintech stays the lender of record.

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Luis Medeiros

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