// US-based Solidity developers · Finance
Free project plan & cost estimate in 48 hours.
Senior Solidity developers for finance and fintech teams, based in the US
Engineers who understand audit trails, reconciliation, and access controls, and who build systems your compliance team can sign off on.
- Interview engineers before you pay anything
- 100% U.S.-based, working your hours
- No brief or spec needed to get started
First 5 Dev Hours Free
Project plan. Roadmap. Cost & ROI estimation.
Real engineers. Real conversations.
Talk to an engineer. Not a salesperson.
Free · No commitment · Project-focused call
Most teams interview matched engineers within a week
Not the right fit? We bring in a replacement
Get your free project plan
Three quick steps. No brief needed.
Free · No commitment · Reply within one business day
// teams we've worked with
“NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag.”
Sound familiar?
- Reconciliation and reporting still depend on manual spreadsheet steps.
- Audit and access-control requirements slow every release.
- Legacy systems hold critical numbers nobody wants to touch.
- Offshore teams struggle with the precision financial data demands.
What our Solidity engineers build for finance and fintech teams
Finance systems
Ledgers, reconciliation, reporting, and integrations with full audit trails.
Smart contracts
Solidity contracts with full test coverage, built for audit.
Security review prep
Code hardened and documented before it goes to an outside auditor.
Comfortable inside your security controls
- We work inside your SOC 2 controls: your access policies, reviews, and change management.
- Audit trails and least-privilege access built in from the start.
- Every engineer is US-based and signs an NDA and IP assignment.
How it works
- 01
Pick a time
Book a 30-minute project call directly in our calendar.
- 02
Talk through the problem
Tell us what needs building, what's stuck and what success looks like. No spec needed.
- 03
Your plan in 48 hours
Get your project plan, roadmap, cost and ROI estimates. The plan is yours to keep.
- 04
First 5 dev hours free
Agree the scope with our team. Decide whether to continue before any paid work begins.
Common questions
Will this turn into a sales pitch?
No. The call is about your project: what needs building, what's stuck, and whether we have the right engineers. If we're not a fit, we'll say so.
What do I get for free?
A project plan, roadmap, cost estimate and ROI estimate within 48 hours of your project call. Your first 5 development hours are free, too. We agree the scope and any paid work with you before proceeding.
Do I need a spec or brief?
No. Tell us the problem in plain words and we'll help shape the scope with you.
Are the engineers really in the U.S.?
Yes. Every engineer lives and works in the United States. No offshore hand-offs, and that's in the contract.
What our clients say
"NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag."
"Their R&D tax credit workflow platform paid for itself in the first filing season."
"AI-native from day one. Our IRS transcript pipeline runs 24/7 without a human in the loop."
"Property tax appeals used to take weeks. Their comp analysis tooling turned it into hours."
"The AI intake agent handles our tier-1 patient calls with a hand-off cleaner than our old call center."
"POS, inventory, ordering — all unified. We finally have one source of truth across every location."
"The procurement platform paid for itself in the first quarter of use."
"They shipped our matching engine in 6 weeks. Our old team would've taken 6 months."
"Enterprise-grade delivery without the enterprise-agency price tag."
"Their team plugged into our sprint on day one. Zero ramp time."
"NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag."
"Their R&D tax credit workflow platform paid for itself in the first filing season."
"AI-native from day one. Our IRS transcript pipeline runs 24/7 without a human in the loop."
"Property tax appeals used to take weeks. Their comp analysis tooling turned it into hours."
"The AI intake agent handles our tier-1 patient calls with a hand-off cleaner than our old call center."
"POS, inventory, ordering — all unified. We finally have one source of truth across every location."
"The procurement platform paid for itself in the first quarter of use."
"They shipped our matching engine in 6 weeks. Our old team would've taken 6 months."
"Enterprise-grade delivery without the enterprise-agency price tag."
"Their team plugged into our sprint on day one. Zero ramp time."
Hire a US-based Solidity developer for financial smart contracts such as ERC-4626 vaults, collateralized lending systems, and controlled settlement workflows. These projects need explicit accounting rules for deposits, withdrawals, fees, and losses. With Solidity 0.8.x, checked arithmetic helps catch overflows, but it does not resolve rounding errors, oracle assumptions, or incorrect asset valuation. Those risks belong in the specification and test plan.
Use Foundry invariant tests, OpenZeppelin components, and Chainlink Data Feed checks where appropriate to examine solvency assumptions and transaction edge cases. Engineering scope should include privileged roles, emergency actions, reconciliation events, and deployment approvals, not just contract functions. NextGen Coding Company engineers work entirely in the US, and we're comfortable working inside a client's SOC 2 security controls. Book a 15-minute call to discuss your financial system.
Frequently asked questions
- What should a Solidity developer test in an ERC-4626 vault?
- Test share conversion, rounding direction, preview functions, deposit limits, and withdrawals under changing asset values. Include donation and inflation attack scenarios, especially around an empty vault. OpenZeppelin's implementation provides useful protections, but strategy-specific accounting still needs verification. Model fees, illiquid positions, and losses so reported total assets do not imply withdrawals the vault cannot fulfill.
- How should lending contracts handle Chainlink oracle data?
- Check the feed address, decimals, answer validity, and update timestamp against the market's requirements. Define what borrowing and liquidation functions do when data becomes stale or unavailable. On relevant L2 networks, account for sequencer uptime and recovery grace periods. An oracle integration needs explicit failure behavior; simply reading the latest answer is not enough.
- How do Solidity teams test lending protocol solvency?
- Define solvency and accounting invariants before implementing the test harness. Exercise deposits, borrowing, repayments, interest accrual, liquidations, and bad debt across varied transaction sequences. Foundry invariant tests can expose state combinations missed by example tests. Include decimal differences, rounding, collateral price shocks, and unsupported token behavior; simulations do not eliminate economic or market risk.
- Can US-based Solidity engineers work within our SOC 2 controls?
- NextGen Coding Company is comfortable working inside a client's SOC 2 security controls. Discuss repository access, approval workflows, secrets handling, and deployment evidence during scoping. For financial contracts, distinguish ordinary development access from authority to upgrade contracts or move assets. Engineers work your hours and join standups, keeping technical decisions inside your team's working process.
- Does a financial smart contract need an independent audit?
- For contracts holding or directing financial assets, independent security review is an important part of release planning, not a substitute for internal testing. Prepare specifications, accounting invariants, dependency versions, and deployment parameters for reviewers. Track findings through remediation and retesting. Audit scope should also clarify whether economic design, oracle configuration, and operational permissions are covered.
- Are your developers really based in the US?
- Yes. Every engineer lives and works in the United States. No offshore subcontracting and no hand-offs to another team. That's written into the contract.
- How fast can someone start?
- Most teams interview matched engineers within a week of the first call. Start dates depend on your interview process.
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