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.