AS2 vs SFTP — which EDI transport protocol should you use?
In short: AS2 and SFTP are two common ways to transmit EDI documents between trading partners. AS2 provides built-in encryption, digital signatures and delivery receipts (MDN); SFTP is a simpler encrypted file transfer without those business-level guarantees unless added separately.
Key capabilities
- AS2 delivery receipts (MDN): AS2 returns a signed Message Disposition Notification confirming exactly when a document was received — a built-in proof of delivery SFTP lacks natively.
- SFTP simplicity: SFTP is a straightforward encrypted file transfer, often used by retailers with simpler infrastructure or lower document volumes.
- Retailer-driven choice: Which protocol you need isn't up to you — it's dictated by each retailer's specification, and larger retailers more often require AS2.
- Both handled automatically: EDIconnect's Web EDI portal manages AS2, OFTP2, SFTP, Peppol and VAN connections under the hood — you work in the portal regardless of which protocol a given retailer requires.
How AS2 and SFTP actually work
AS2 (Applicability Statement 2) is a protocol designed specifically for exchanging structured B2B documents over HTTP/HTTPS. It packages the EDI file with encryption and a digital signature, and the receiving party returns a Message Disposition Notification (MDN) — itself signed — confirming the exact document was received intact. This built-in, verifiable receipt is why many large retailers standardized on AS2: it provides evidence of delivery without needing a separate acknowledgment process.
SFTP (SSH File Transfer Protocol) is a general-purpose method for securely transferring files over an encrypted SSH connection. It doesn't have a concept of 'documents' or built-in delivery receipts — it simply moves files from one location to another securely. For EDI purposes, SFTP is often paired with a separate acknowledgment message (like an EDIFACT CONTRL or X12 997) to confirm receipt, since the protocol itself doesn't provide one.
Choosing between them isn't really your decision
In practice, a supplier rarely gets to choose between AS2 and SFTP freely — each retailer's EDI specification dictates which protocol (or protocols) it supports, and the supplier has to comply. Some retailers offer a choice; others mandate AS2 specifically because of its non-repudiation properties, particularly for high-value transactions like invoices.
This is one of the reasons Web EDI exists: rather than a supplier needing to set up and maintain both an AS2 gateway and an SFTP client internally, EDIconnect's platform handles the required transport for each retailer automatically. You work from a consistent web portal or through your ERP, and the platform manages whichever protocol — AS2, OFTP2, SFTP, Peppol or VAN — each trading partner requires behind the scenes.
Frequently asked questions
What is the main difference between AS2 and SFTP for EDI?
AS2 is a transport standard built specifically for B2B document exchange, with encryption, digital signatures and a signed receipt (MDN) confirming delivery. SFTP is a general-purpose secure file transfer protocol that encrypts data in transit but doesn't include a built-in business-level delivery receipt.
Which protocol do most retailers require?
It varies by retailer. Some require AS2 specifically for its non-repudiation and delivery-confirmation properties, while others accept SFTP, especially for lower-volume or simpler integrations. EDIconnect configures whichever protocol each of its 30+ supported retailers requires.
Is AS2 more secure than SFTP?
Both encrypt data in transit. AS2 adds digital signing and a delivery receipt (MDN) that provides evidence a specific document was received, which SFTP does not provide by default.
Do I need to choose AS2 or SFTP myself?
No. With EDIconnect's Web EDI portal, the required protocol per retailer is configured automatically as part of onboarding — you don't need to set up or manage the transport layer yourself.
Can the same company use AS2 with one retailer and SFTP with another?
Yes, and this is common. A supplier connected to several retailers often ends up using a mix of protocols depending on each partner's requirements, all managed centrally through the Web EDI portal.
Is Peppol related to AS2 or SFTP?
Peppol is a separate network and message exchange framework, increasingly used for e-invoicing across Europe. EDIconnect supports Peppol alongside AS2, OFTP2, SFTP and VAN connections.