Supplier Self-Service Onboarding Portal: Kill the Email Ping-Pong
Send a prospective supplier one link, let them fill in their legal/tax/banking/remit-to details and upload required documents, run automatic completeness and consistency checks, then have procurement review and approve before the record ever touches your vendor master.
A web tool where you email a supplier a unique invite link, they self-enter their legal, tax, banking, and remit-to details and upload required documents, the tool runs completeness/format/consistency checks and a duplicate guard on tax ID, your reviewer verifies and approves (or requests fixes), and only approved suppliers are committed with a vendor number and exported as a CSV in your ERP's vendor-master format with documents stored securely.
Before you start
- A Supabase account (free)
- A Vercel account (free)
- A Resend account (free)
- Your ERP's vendor-master import column layout
- A list of the documents you require (W-9/W-8, insurance, certifications) and their rules
- Claude Code or any AI coding agent
The problem this kills
Onboarding a new supplier is death by email. You send a blank form, they send back half of it, you ask for the W-9, they attach the wrong year, you ask for their insurance certificate, it's expired, you ask for banking details, they reply with a typo in the IBAN, and somewhere in that thread are three different spellings of their legal name. Eventually someone in procurement or AP gives up and re-types the whole mess into the ERP's vendor master — which is exactly where a transposed tax ID or a wrong remit-to address turns into a misdirected payment.
It's slow, it's error-prone, and the worst failures are silent: a duplicate vendor created because nobody checked the tax ID, a payment sent to the wrong bank, an expired insurance cert that nobody flagged. You don't need to live in that inbox, and you don't need to be a developer to fix it.
What you'll build
A secure self-service portal. You send a prospective supplier a unique invite link. They open a clean form and enter their own legal name, DBA, tax ID, address, remit-to, currency, payment terms, contacts, and banking details, and they upload the documents you require (W-9/W-8, insurance certificate, certifications). As they submit, the tool runs automatic checks — required fields present, tax-ID format valid, required documents attached and not expired, and bank/country consistency — and it runs a duplicate guard on the normalized tax ID (plus legal name) so the same supplier can't slip in twice. Your procurement or AP reviewer then opens a clean review screen, verifies the submission and the documents, and either requests fixes (which re-opens the supplier's link) or clicks Approve. Only on approve does the tool assign a vendor number, write the audit record, and produce a CSV in your ERP's exact vendor-master import columns with the documents stored safely alongside. Nothing is ever committed straight from raw supplier input.
What's inside the Implementation Plan
The downloadable plan is a step-by-step file you paste into an AI coding agent. It opens by interviewing you about your business — how you onboard suppliers today, which ERP you import vendors into and its exact column names, your tax-ID and bank conventions across the countries you buy from, which documents are mandatory and their expiry rules, your typical and peak onboarding volumes, your approval and segregation-of-duties rules, and your messy edge cases — and then it tailors the form, the validations, the dedupe key, and every later step to your answers. This is not a generic template; the agent reflects a short spec back to you and waits for your thumbs-up before it builds anything. From there it walks the agent through the invite-link flow, the supplier form and document uploads, the automatic checks and duplicate guard, the reviewer verify-and-approve screen, the vendor-number assignment, and the vendor-master CSV export — each step with a ready-to-copy prompt. There's also a fallback so you can build and use the whole thing today even with no API into your ERP.
The governance it includes (this is the point)
This tool touches banking details and your vendor master, so it ships with the controls procurement and finance actually need: login so only your team can review and approve, row-level security so you only ever see your own organization's suppliers, a complete audit trail of who reviewed, requested fixes, approved, and exported — and when, a hard human-in-the-loop approval gate so no vendor number is assigned and nothing is exported to the ERP until a reviewer signs off on the raw supplier input, and duplicate guards keyed on the normalized tax ID (plus legal name) that block a duplicate supplier right at submission. Suppliers fill in their own data through a scoped invite link; reviewers verify it; the system commits nothing on its own.
Who it's for
Procurement leads, AP teams, and vendor-master owners who onboard suppliers today through a tangle of email attachments and manual re-keying into the ERP. If you can describe the data and documents you need from a new supplier and the rule for who approves them, you can build this.
You've got this — start with the plan, paste the first prompt, answer the interview, and you'll see your first supplier invite link working the same afternoon.