Frequently Asked Questions

Greenstamp is an AI copilot for accounting firms. It handles the volume work — bulk invoicing, bill capture, bank reconciliation, SAT code suggestions, pre-stamp validation — and queues everything for your team to review and approve. Your accountants stay in control; the copilot gives them leverage.

Greenstamp is built for accountants and accounting firms who want to give their team better leverage on CFDI work. We're especially popular with firms serving 50-150 clients who want their experienced accountants spending more time on advisory and less on data entry.

No. Greenstamp is a copilot, not a replacement. Your team keeps the judgment calls, the client relationships, and the final approval on every CFDI. The copilot handles the repetitive volume work — line items, SAT codes, reconciliation, validation — so your accountants can spend their time where it actually matters.

Most invoicing software is designed for individual businesses—one company, one account. Greenstamp is built for accounting firms that manage dozens or hundreds of clients. Our multi-client dashboard, white-label portals, and approval workflows are designed specifically for how accountants work.

Yes! Greenstamp is available in English, Spanish, French, and German. You can switch languages at any time, and your client portals also support multiple languages.

You'll need your clients' digital signing certificates from the local tax authority. These are the certificates that allow invoices to be signed. If any client doesn't have theirs yet, we can guide you through the process of obtaining them.

Initial setup takes about 15 minutes. After that, adding each new client takes around 5 minutes—upload their certificate, configure their portal, and they're ready to create invoices.

No. Greenstamp is cloud-based, so your clients can create invoices from anywhere—their office, home, or on the go. They just need internet access and their portal credentials.

Yes. You can import client information via CSV, including tax IDs, tax data, and regime setup. We also support bulk upload of tax registration documents to streamline onboarding.

We can guide you through the process of obtaining signing certificates from the relevant tax authority. Contact us and we'll walk you through the steps for your jurisdiction.

Each client gets their own white-label portal where they can create invoices, view their history, and download XMLs and PDFs. When they create an invoice, it comes to you for approval before being stamped.

Your clients see a clean, simple portal with your branding. They can create invoices, view previous invoices, and download receipts. They don't see other clients or your admin dashboard.

Our AI validation catches common errors before the invoice reaches you. If there's an issue, the client sees a clear message explaining what to fix. You can also reject invoices with notes if additional changes are needed.

Yes. You can configure permissions per client—some can only create invoices, others can view full history. You can also require approval for all invoices or allow auto-stamping for trusted clients.

Yes. Client portals can be configured under your own domain (e.g., portal.yourfirm.com) with your logo and colors. Your clients see your brand, not ours.

Electronic invoicing is the digital, government-mandated equivalent of a paper invoice. Many countries now require businesses to issue tax-validated electronic invoices for all transactions. Learn more in our E-Invoicing Guide →

Greenstamp's AI validation catches most errors before submission. If you need to fix an invoice after it's been registered, you can initiate a cancellation through our platform — we follow the timing and acknowledgement rules of the relevant tax authority. Learn about cancellation rules →

Every invoice goes through our AI-powered validation before submission, checking against the relevant tax authority's current requirements. Once accepted, invoices are certified and registered with the tax authority. You receive a validated electronic invoice with a unique identifier — proof that the tax authority has validated it.

Yes. When you record payments against invoices with deferred payment terms, Greenstamp automatically generates and submits any required payment-complement documents. We track payment allocations and ensure compliance with the tax authority's reporting requirements.

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Yes. We use AES-256 encryption for all data at rest and in transit, including signing certificates. Our infrastructure is built on enterprise-grade cloud services with SOC 2 Type II compliance. We never share your data with third parties.

Your data is stored in secure, geographically redundant data centers. Signing certificates are stored in isolated, encrypted vaults with strict access controls. All data handling complies with applicable data protection regulations.

Certificates are encrypted with AES-256 and stored in isolated vaults. They're only decrypted momentarily during the invoice signing process, and access is logged and audited. Certificate passwords are never stored in plain text.

You control who has access to your Greenstamp account. You can invite team members with different permission levels—some users can create invoices while others have admin access. All access is logged for audit purposes.

All customers receive email and chat support with responses within 24 hours. Our team understands the unique challenges of running a multi-client accounting practice.

Support is available 24/7 via email and chat, with responses during business hours (9am-6pm CT, Monday-Friday). Urgent issues are prioritized and addressed as quickly as possible.

Yes. We provide guided onboarding to help you set up your account, upload client certificates, and create your first invoice. We'll make sure your team is comfortable using Greenstamp before we consider you fully onboarded.

Yes. We offer training sessions for teams that need it. We also have a library of tutorial videos and guides that your team can reference at any time.