InvoiceProof vs Medius vs OpenEnvoy: AP Fraud Tools Compared

What invoice fraud detection software does

Invoice fraud detection software inspects the invoices your accounts-payable (AP) team receives and flags the ones that look fraudulent, duplicated, or out of policy before money leaves the building. It sits between the invoices a vendor (or an attacker pretending to be a vendor) sends you and the moment you approve a payment.

The fraud these tools target is expensive and common. The two biggest categories are duplicate payments — the same invoice paid twice, whether by accident or by design — and business email compromise, where a fraudster impersonates a real vendor and tricks you into wiring money to a new bank account. Good detection software also catches inflated amounts, invoices with no matching purchase order, and amounts that exceed what a purchase order authorized.

The core checks you should expect from any tool in this category are:

• Duplicate detection — exact and modified duplicates of an invoice number or amount.
• Bank-account-change detection— a vendor's payment details suddenly differ from what is on file, the classic redirect-fraud signal.
• Purchase-order (PO) matching — confirming the invoice ties back to an authorized PO and does not exceed its amount.
• Anomaly and pattern checks— round-dollar amounts, math errors, and address mismatches that do not fit the vendor's normal behavior.

Where the products differ is scope and posture. Some are full AP automation platforms that happen to include fraud detection; others are focused screening tools you point at an invoice batch. The right pick depends on how big your AP operation is, whether you want to replace your workflow or just add a check on top of it, and how much you care about being able to prove what you screened. The comparison below lays out the three options against the criteria that actually decide the choice.

InvoiceProof vs Medius vs OpenEnvoy: comparison table

The table below summarizes the three tools on the criteria buyers ask about most. Competitor rows reflect information published on the Medius and OpenEnvoy public websites as of June 2026; where something is not stated publicly, we say so rather than guess. Always confirm current details and pricing directly with each vendor.

When to use InvoiceProof

InvoiceProof is built for teams that want fraud screening they can use today, without a procurement cycle. It runs a free sandbox scan with no account and no credit card, returning results in under 100ms, so you can test it against your own invoice data before you ever talk to anyone. Each scan produces a unique proof ID, which turns a single fraud check into a durable, citable audit record.

InvoiceProof is the strongest fit when:

1. You run a company in the roughly 20–500 employee range and an enterprise AP suite is more platform — and more cost — than you need.
2. You want to try the tool instantly against real invoices rather than sitting through a demo before you can evaluate detection quality.
3. You need a proof record for every scan — a referenceable artifact you can hand to a controller, auditor, or insurer to show exactly what was checked and when.
4. You want a public scan API to screen batches programmatically inside your existing workflow instead of replacing it.
5. You prefer transparent, published pricing: a $750 pilot covering 100 invoices over 30 days, with subscriptions from $1,500 to $3,500 per month.

The detection coverage is deliberately focused on the patterns that drive real losses: bank-account changes, modified duplicates, missing POs, PO overages, vendor address mismatches against the vendor master, line-item math errors, and suspicious round-dollar amounts — each returned with a severity level so your team triages the riskiest invoices first. To be clear about the trade-off: InvoiceProof is a screening and proof tool, not a full AP automation platform. If you need end-to-end invoice capture, coding, approval routing, and payment execution in one system, the two enterprise suites below are stronger.

When to use Medius

Medius is an accounts-payable automation suite with a dedicated Fraud & Risk Detection capability, aimed at mid-size to large enterprises. Rather than being a standalone fraud-screening tool, it folds fraud controls into a broader platform that handles the full AP lifecycle — invoice capture, coding, approvals, and payment — so detection happens inside the same system your team already works in.

Based on the Medius public website as of June 2026, its fraud and risk features include duplicate detection, supplier bank-change detection, anomaly detection, four-eyes approval (segregation of duties), and step-up two-factor authentication for sensitive actions. Note that Medius brands this as bank-change and anomaly detection rather than using the "business email compromise" label directly.

Consider Medius when:

• You are a mid-size to large enterprise and want fraud controls embedded in a complete AP automation platform, not bolted on.
• You value process controls like four-eyes approval and step-up authentication as much as the detection itself.
• You have the budget and implementation appetite for an enterprise rollout and a sales-led purchase. Medius does not publish pricing; expect a demo and a custom quote.

API availability for Medius is not publicly stated as of June 2026, and we found no free trial you can start without an account — confirm both with their sales team if they matter to your evaluation.

When to use OpenEnvoy

OpenEnvoy positions itself around "autonomous finance" — verifying invoices in real time before they are paid — and targets both enterprise and mid-market buyers. Its emphasis is on catching problems at the verify-before-pay step so bad invoices never reach the payment run.

Based on the OpenEnvoy public website as of June 2026, its verified features include real-time invoice verification, duplicate detection, 3-way PO matching, and bank-account-change detection. OpenEnvoy publicly documents business email compromise and vendor-impersonation scenarios, and lists 24+ ERP integrations including SAP, Oracle/NetSuite, and Microsoft Dynamics. It also publishes public REST API documentation, although obtaining credentials requires being a customer.

Consider OpenEnvoy when:

• You want real-time, pre-payment verification as a gate on every invoice rather than a periodic batch review.
• You need deep ERP integration — OpenEnvoy advertises 24+ integrations across major enterprise systems.
• You operate at enterprise or mid-market scale and are comfortable with a sales-led purchase. OpenEnvoy does not publish pricing; expect a demo and a custom quote, and we found no self-serve free trial.

Of the three, OpenEnvoy and InvoiceProof overlap most on the specific fraud signals they name publicly. The practical difference is posture and access: OpenEnvoy is an enterprise platform you adopt through sales and integrate with your ERP, while InvoiceProof is something you can try in your browser in seconds and run as a focused check with a proof record attached.

How to choose between them

Run your decision through this short sequence and the right answer usually becomes obvious:

1. Match the tool to your size. Under ~500 employees and you mostly need screening? Start with InvoiceProof. A large or mid-market enterprise replacing its AP workflow? Shortlist Medius and OpenEnvoy.
2. Decide platform vs. point check. If you need capture, coding, approvals, and payment in one system, choose a suite. If you already have a process and just want a fraud gate on top, choose a focused tool.
3. Confirm the detection coverage you actually need — bank-change, modified duplicates, and PO matching are table stakes; verify each shortlisted tool against your own invoice data.
4. Check whether you can try before you buy. Only InvoiceProof offers a free, no-account trial; the enterprise suites are demo-and-quote.
5. Ask whether each scan leaves you with proof.If you need an audit-ready record per check, InvoiceProof's proof ID is a differentiator.

Framed fairly: Medius and OpenEnvoy are the stronger choice for full enterprise AP automation, with broad workflows, ERP integration, and process controls. InvoiceProof's edge is the combination of an instant free try, a proof record on every scan, and pricing built for small and mid-size businesses.

Try InvoiceProof free — no account required

The fastest way to compare detection quality is to run your own invoices through each tool. With InvoiceProof you can do that right now: paste or upload an invoice batch and get a fraud scan back in under 100ms, with a proof ID attached — no account, no credit card, no sales call. Try InvoiceProof free — no account required.