Supplier bank-detail change checks for small finance teams
Supplier bank-detail change checks for small finance teams is a SaaS idea for finance managers and bookkeepers at businesses with 10 to 200 staff, priced to test at $49 a month per business. Fraudsters send convincing emails asking to update a supplier’s bank account, and a busy bookkeeper changes it. With it, small finance teams verify every supplier bank-detail change with a call-back and a second approver before anyone pays.
. A starting point we wrote, not market research: run the 7-day test before you build.
What problem does it solve?
Fraudsters send convincing emails asking to update a supplier’s bank account, and a busy bookkeeper changes it. The next payment goes to the fraudster, and getting it back is hard.
Why now: AI makes fake supplier emails more convincing, and insurers ask what checks a business runs before it pays.
What do they use today?
Many small finance teams rely on the bookkeeper’s judgement and sometimes a quick call. The check is rarely written down, and the new details go straight into the payment records.
How does it work?
When an email arrives asking to change a supplier’s bank account, the bookkeeper logs it as a change request that stays on hold. They then ring the supplier on a number already on file and record the call-back in the request. A second person approves before the new details go live, and every step is kept in an audit trail with an alert to the team.
What goes in the first version?
- A supplier list with verified bank details and contact numbers
- Change requests logged and held until verified
- A call-back record, to a number already on file
- A second person’s approval before new details go live
- Alerts and a full audit trail for every change
Who pays, and how much?
- Who pays
- Finance managers and bookkeepers at businesses with 10 to 200 staff
- Price to test
- $49 a month per business
A flat price per business suits a small finance team, where one manager decides alone and a few people share the work. It adds a written record to a check that depends on judgement today.
How to test it in 7 days
- 1Ask five bookkeepers how they check a supplier’s new bank details today.
- 2Read small-business subreddits for stories of fake bank-detail emails and note which checks failed.
- 3Put up a page that takes pre-orders and share it with finance managers you know.
Where to find the first customers
- Bookkeeper and small-business finance groups on LinkedIn
- Accounting firms that pay bills for their clients
- Insurance brokers who sell cyber and crime cover
What are the risks?
- Holding bank details makes the tool a target, so security must be strong from day one.
- Banks and accounting tools keep adding payee checks, so focus on the approval record.
How to build it on shipanysaas
5 of the parts it needs are already in the kit. Get the kit, open it in Claude Code, Codex or Cursor, and paste the starting prompt.
- Already in the kit
- Sign-in
- Teams and roles
- Billing
- Emails
- In-app notifications
- You build
- Supplier register with verified details
- Change requests with call-back records
- Two-person approval and audit trail
See the starting prompt
You are in a fresh copy of the shipanysaas starter kit, a pnpm and Turborepo monorepo: the Next.js web app is in apps/web and the Supabase database, with its migrations, in apps/web/supabase. Help me build the first version of Supplier bank-detail change checks for small finance teams. Read AGENTS.md first, then the AGENTS.md in every folder you work in: the kit's rules there win over your defaults. When a skill in .agents/skills (also in .claude/skills and .cursor/skills) matches a task, use it. ## The product - What it does: Small finance teams verify every supplier bank-detail change with a call-back and a second approver before anyone pays. - Who pays: Finance managers and bookkeepers at businesses with 10 to 200 staff - Their problem: Fraudsters send convincing emails asking to update a supplier’s bank account, and a busy bookkeeper changes it. The next payment goes to the fraudster, and getting it back is hard. - Price to test: $49 a month per business (a plan in apps/web/config/billing.config.ts) ## Build only this first version 1. A supplier list with verified bank details and contact numbers 2. Change requests logged and held until verified 3. A call-back record, to a number already on file 4. A second person’s approval before new details go live 5. Alerts and a full audit trail for every change ## Already in the kit: reuse it, never rebuild it - Sign-in: email and password or Google, plus magic links and passkeys you can switch on - Teams and roles: team accounts with members, roles and invitations - Billing: Stripe or Lemon Squeezy subscriptions, per seat or usage-based, and one-off payments - Emails: transactional email through Resend or Nodemailer - In-app notifications: a notifications bell in the web app ## New code it needs - Supplier register with verified details - Change requests with call-back records - Two-person approval and audit trail ## How to work 1. Plan first: list the database tables (with row-level security, so each team only sees its own rows), the pages and the server actions for the first feature. Then stop and wait for my OK. 2. Build one feature at a time with the kit's own UI and form components, with a migration for every schema change and user-facing text in the translation files. 3. After each feature, run the verification steps in AGENTS.md, fix what they find, and tell me what you built and what comes next. ## Rules - Ask me before you add a dependency, delete a file, or change sign-in, billing or the admin panel. - Leave the parts of the kit this product doesn't use as they are. Done when every first-version feature works for a signed-in team and the AGENTS.md checks pass.
Guides for the parts it uses
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