// US-based FastAPI developers · Finance
Free project plan & cost estimate in 48 hours.
Senior FastAPI 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.
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// 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 FastAPI engineers build for finance and fintech teams
Finance systems
Ledgers, reconciliation, reporting, and integrations with full audit trails.
APIs & microservices
Typed FastAPI services with auto-generated docs.
AI & data back-ends
APIs serving models, search, and data pipelines.
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 US-based FastAPI developers to build financial APIs, payment integrations, and reconciliation services in Python. For this stack, engineering decisions often center on Pydantic v2 validation, SQLAlchemy 2.0 transactions, and PostgreSQL data integrity. Payment webhooks need idempotency, monetary values need decimal-safe handling, and ledger updates need clear transaction boundaries so retries do not create duplicate entries or inconsistent balances.
NextGen Coding Company provides senior engineers who live and work in the US, without offshore subcontracting. They work your hours and join your standups while addressing issues such as blocking calls in async routes or Alembic migrations on active financial tables. We're comfortable working inside your SOC 2 security controls, and we sign an NDA and full IP assignment before touching code.
Frequently asked questions
- What should I look for when hiring a FastAPI developer for financial software?
- Look for more than Python fluency. A finance-focused interview should cover Decimal arithmetic, database isolation, idempotent payment requests, and audit trails. Ask candidates to explain a failed webhook retry and how they would test recovery with pytest. Strong answers distinguish API validation from transactional guarantees enforced in PostgreSQL.
- Can FastAPI handle payment webhooks and ledger integrations?
- FastAPI can expose webhook endpoints and coordinate ledger integrations, but reliability depends on the surrounding design. Verify provider signatures, persist event identifiers, and make processing idempotent. For durable work, use a queue such as Celery with RabbitMQ rather than relying on in-process BackgroundTasks for payment processing.
- How should a FastAPI financial API handle authentication and audit logging?
- Start with your identity provider and authorization model, then enforce scopes and resource permissions at each endpoint. Validate token signatures, issuer, and audience rather than merely decoding JWTs. Audit records should capture relevant actions without exposing credentials or sensitive financial payloads. We can work within your existing SOC 2 security controls.
- How do you prevent async database problems in FastAPI finance applications?
- Use SQLAlchemy 2.0 AsyncSession with an async driver such as asyncpg, and give each request or task its own session. Keep blocking SDK calls off the event loop. For financial writes, explicitly review transaction boundaries, locking, and retry behavior; async execution alone does not protect against concurrent balance updates.
- How quickly can we interview a US-based FastAPI finance developer?
- Most teams interview matched engineers within a week of the first call. Book a 15-minute call to outline your FastAPI version, payment providers, ledger architecture, and security review process. Our engineers work your hours and attend standups. If the fit isn't right, we arrange a replacement with a proper hand-over.
- 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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