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Generate a full Fintech SaaS from a prompt

Ledgers, transactions, KYC records, audit tables. StackAlchemist generates the data model and CRUD layer for a fintech SaaS as a .NET 10 + Next.js 16 codebase. Compile-verified. Owned. Deployed in your own compliance perimeter.

What you get

A production-shaped fintech SaaS starter with:

  • Accounts and ledger tables — Account, AccountType, AccountBalance and LedgerEntry entities with debit, credit and balance-after columns for double-entry bookkeeping
  • Transactions — Transaction and ReconciliationRecord entities with typed categorization, reconciliation flags and an idempotency-key column
  • KYC records — Customer, KycProfile and KycCheck entities with vendor, reference and status fields
  • Audit events — AuditEvent and AuditActor entities with before/after values
  • Payment methods — PaymentMethod, Institution and BankLink entities that store a token from your PCI-compliant vault, never card data
  • Webhook records — Webhook and WebhookDelivery entities to log inbound partner events
  • Statements and reports — Statement and Report entities
  • .NET 10 minimal API — a Dapper repository and CRUD endpoints for every entity, documented with OpenAPI
  • Next.js 16 frontend — TypeScript types, a typed API client and starter pages for your entities
  • PostgreSQL migration — UUID keys, foreign keys, row-level security enabled (the policies are yours to write)
  • Docker Compose for local development

What you wire yourself: the double-entry posting logic and idempotency enforcement, writing an audit event on every mutation, the KYC vendor call (Jumio, Persona, Alloy, or your own), webhook handlers for Stripe, Plaid or your bank partner, authentication with MFA and scoped roles for customer, ops, admin and auditor (the Supabase client is preinstalled; the auth flows are yours to write), background reconciliation jobs, ops dashboards and regulator exports, tests, and your CI pipeline. The entities carry the fields those features need; the feature code is yours.

All compile-verified. Owned outright. No platform dependency.

Why a generated fintech codebase is the right call

Compliance requires ownership. You cannot run a fintech SaaS on someone else's platform and claim to control the data. Regulators want to know where the data lives, who can access it, and how it is audited. An owned codebase running in your VPC is the only honest answer.

Audit trails are non-negotiable. Every hosted platform has audit logging, but typically through their API. Regulators want the audit trail in your database, under your retention policy, with your encryption keys.

KYC vendor choice is a competitive issue. Each KYC vendor has different cost, different coverage, and different UX. Locking into a platform's KYC vendor locks you out of optimization. With an owned codebase, you put the vendor behind your own interface and swap it when the economics change.

The surface area is large. A real fintech SaaS has more surface area than most SaaS. Accounts, ledgers, transactions, reporting, KYC, AML, reconciliation — plus the user-facing product on top. Generating the boilerplate buys you weeks of work.

Who this is for

  • Fintech founders in the "we have a design partner and need to ship" stage, pre-seed or seed.
  • Embedded finance teams at non-finance companies — payroll, B2B SaaS, marketplaces adding financial features.
  • Compliance-heavy verticals like neobanks, trade finance, insurance-tech, crypto-on-ramp.
  • Engineering teams at larger fintechs scoping a new product line who want a verified starter rather than a blank slate.

Example entities generated

A typical fintech generation produces:

  • Account / AccountType / AccountBalance
  • Transaction / LedgerEntry / ReconciliationRecord
  • Customer / KycProfile / KycCheck
  • PaymentMethod / Institution / BankLink
  • AuditEvent / AuditActor
  • Statement / Report
  • Webhook / WebhookDelivery

The shape adapts to your prompt. A neobank has different entities than a B2B AP automation tool.

Real example: Invoice financing startup

Imagine you spec this:

"We help small businesses get instant cash for unpaid invoices. A customer creates an account, uploads an invoice PDF, gets a quote, and funds their account via Stripe. We lend them 80% of the invoice value immediately. When the invoice is paid, the customer repays us with fees. Every transaction and state change is logged for audits. We integrate KYC with Persona to verify business owners. Admin team needs a dashboard to see all loans, flag issues, and export reports for the bank."

StackAlchemist generates:

  • Account entity with account_number, account_type (escrow, liability, revenue), balance, currency
  • Customer entity with name, business_id, created_at, kyc_status, kyc_verification_id
  • KycProfile entity with customer_id, legal_name, dob, address, business_structure
  • KycCheck entity with kyc_profile_id, vendor (Persona), vendor_reference_id, status (pending, approved, rejected), created_at
  • Loan entity with customer_id, invoice_id, principal_amount, fee_amount, status (active, repaid, defaulted), created_at, due_at
  • Transaction entity with from_account_id, to_account_id, amount, type (loan_draw, repayment, fee), idempotency_key, created_at
  • LedgerEntry entity with account_id, transaction_id, debit_amount, credit_amount, balance_after (for the audit trail)
  • AuditEvent entity with actor_id, entity_type, entity_id, action (created, updated, deleted), old_value, new_value, ip_address, created_at
  • PaymentMethod entity with customer_id, type (bank_account), token (from your PCI vault), is_default
  • Webhook and WebhookDelivery entities for logging inbound Stripe and bank partner events, with attempt and status fields for retries
  • Statement and Report entities for monthly statements and compliance exports
  • CRUD endpoints for every entity (/api/v1/customers, /api/v1/loans, /api/v1/transactions, …). Endpoints like POST /customers/:id/kyc-verify or GET /reports/:id/export can be declared in Advanced Mode; the logic behind them is yours to write
  • Next.js types and a typed API client for every entity, plus starter pages

The generated codebase is the schema and CRUD layer for all of that, compile-verified. The behavior on top is yours to write: logging every financial action with actor, timestamp, and before/after state; posting double-entry pairs, so a loan draw debits the customer account and credits a principal-owed account; deterministic reconciliation. The generated codebase does not call your bank partner and ships no webhook handlers, but the account-ledger tables and webhook records are ready for the ACH or real-time payment rails you have chosen.

After you own the code: two next steps

Once the repo is yours:

  1. Integrate your KYC vendor and test the verification flow. The repo gives you KycProfile and KycCheck with vendor, reference and status (pending, approved, rejected) fields. Write a KycService interface and a Persona implementation (or Jumio, Alloy, whatever you chose in your spec), sign up for an API key, and record each check as a KycCheck row with an AuditEvent alongside it. Run a few test verifications against the vendor's sandbox. No compliance work yet, but you have built the first gate.

  2. Wire your bank or fintech partner's API and test a transaction end-to-end. Write a TransactionService that submits a real ACH batch or payment-rail call, a webhook handler for the confirmation, and the posting logic that writes the LedgerEntry pairs. Enforce idempotency on the idempotency_key column (a unique constraint plus a check in the service), so the same transaction request submitted twice creates only one ledger entry and you can retry safely. You now have a loan that can actually be funded and repaid, with an audit trail your auditor can walk.

A note on compliance

A generated codebase is a starting point, not a compliance certification. StackAlchemist hands you a well-structured starting point: the ledger, KYC and audit tables with a compile-verified CRUD layer. Audit logging, role scoping and the KYC integration are yours to build on it. The work of actually achieving compliance (SOC 2, PCI, state-by-state money transmitter licensing, bank partnerships) is still yours. We just put you further along the starting line.

We do not certify our generated code as compliant. We build it so that compliance is achievable. That distinction matters.

What is not included

We do not provide banking-as-a-service rails. You partner with Unit, Bond, Treasury Prime, Adyen, or whoever you have picked, and you write the integration that talks to them on top of the generated ledger. We do not include card issuance, ACH processing, or FX — those are vendor-specific and you plug them in.

Pricing

One-time, per generation. Simple Mode (describe it in plain English) and Advanced Mode (define the entities step by step) are two ways to describe your app; the tier decides what you get.

  • Blueprint — $299. schema.json (the entity-relationship model) and api-docs.md (the CRUD contract, endpoint by endpoint). Documents, no code.
  • Boilerplate — $599. The repository described above, put through its real compilers before delivery (the Compile Guarantee).
  • Infrastructure — $999. Boilerplate plus an AWS CDK stack, a Terraform AWS baseline, a Helm chart and a DEPLOYMENT.md runbook.

No monthly fee. No per-transaction fee. You generate, you own, you operate.

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