PCI DSS vs PCI S3 is one of the most common points of confusion in payment security. Both come from the PCI Security Standards Council (PCI SSC), and both protect payment data, but they apply to different things. PCI DSS secures the environment where an organization handles cardholder data. PCI S3 secures the payment software itself. This blog explains each standard, compares them side by side and shows which one applies to your organization.

What is PCI DSS Compliance?

The Payment Card Industry Data Security Standard (PCI DSS) is the PCI SSC’s baseline of security requirements for any organization that stores, processes or transmits cardholder data, or can affect the security of that data. It covers the people, processes and technology in an organization’s cardholder data environment.

PCI DSS is built around 12 requirements grouped under six goals, including network security, data protection, access control, monitoring and security policies. The current version is PCI DSS v4.0.1, published in June 2024; v4.0 was retired on 31 December 2024, and its future-dated requirements became effective on 31 March 2025.

Compliance is validated every year. Depending on transaction volume and payment brand rules, an organization completes either a Report on Compliance (ROC) with a Qualified Security Assessor (QSA) or a Self-Assessment Questionnaire (SAQ). For a full introduction, read SISA’s beginner’s guide to PCI DSS compliance.

What is PCI S3 Compliance?

The PCI Secure Software Standard (PCI S3) sets security requirements for software that handles payment data or payment-related functions. Instead of assessing an organization, it assesses a specific software product: how it is designed, built and maintained to protect payment data and resist attack.

PCI S3 is part of the PCI Software Security Framework (SSF), alongside the Secure Software Lifecycle (Secure SLC) Standard, and it replaced PA-DSS, which closed in October 2022. On 15 January 2026, the PCI SSC published PCI Secure Software Standard v2.0, which bases scope on the sensitive assets software handles and brings SDKs, including 3DS SDKs, into scope.

A PCI SSC-qualified Secure Software Assessor validates the product, and once accepted, it is listed on the PCI SSC website. For the full process, read SISA’s guide to PCI S3 certification.

PCI DSS vs PCI S3 Compared

The core difference in PCI DSS vs PCI S3 is what gets assessed: PCI DSS assesses an organization’s environment, while PCI S3 assesses a software product.

In short, PCI DSS answers “Is this organization handling card data securely?” whereas PCI S3 answers “Is this software built to handle payment data securely?”

PCI DSS or PCI S3: Which One Applies to Your Organization?

Which standard applies to you depends on whether your organization handles cardholder data, builds payment software for others, or both.

Three points help clarify the choice:

1. Validated software does not replace PCI DSS. A merchant using PCI S3-validated software still needs PCI DSS compliance for its own environment. The software must also be installed and configured as the vendor’s implementation guidance specifies.

2. PCI DSS covers in-house software. Organizations that build payment applications solely for their own use do not need a separate PCI S3 certification, as the PCI Secure Software Standard is not intended for such software. Instead, the software is assessed as part of their PCI DSS compliance, under the secure development requirements for bespoke and custom software in Requirement 6.

3. The two standards support each other. PCI S3-validated software gives merchants and service providers independent evidence of the software’s security, which supports their PCI DSS assessment. It does not, on its own, reduce PCI DSS scope.

If your business runs payment operations and sells payment software, plan for both. A combined gap assessment can show where controls overlap and avoid duplicate work.

Conclusion: Two Standards, One Goal

The PCI DSS vs PCI S3 question comes down to scope. PCI DSS protects the environment where organizations handle cardholder data, while PCI S3 protects the software that handles payment data. Merchants and service providers need PCI DSS; payment software vendors need PCI S3; and many payment businesses need both.

SISA is a PCI Qualified Security Assessor (QSA) and a PCI SSC-qualified Software Security Framework assessor, supporting organizations across PCI DSS compliance and PCI S3 validation. A single gap assessment can show which standards apply to you and where your controls already overlap.

FAQs

1. What is the main difference between PCI DSS and PCI S3?

PCI DSS assesses how an organization protects cardholder data across its environment. PCI S3 assesses whether a specific software product is designed and built to protect payment data.

2. Does PCI S3-validated software make a merchant PCI DSS compliant?

No. Validated software provides independent evidence of the software’s security, but the merchant must still meet PCI DSS for its own environment and implement the software as the vendor’s guidance specifies.

3. Do payment software vendors need PCI DSS compliance?

Only if they store, process or transmit cardholder data, or can affect its security, for example by hosting or supporting customer systems that handle card data. Otherwise, PCI S3 is the relevant standard for their products.

4. Are PCI DSS and PCI S3 mandatory?

The PCI SSC sets both standards but does not enforce them. Payment brands and acquirers require PCI DSS compliance, while PCI S3 validation is usually required commercially by acquirers, banks and enterprise customers.

5. Can one assessor handle both PCI DSS and PCI S3?

Yes, if the firm is qualified for both programs. SISA, for example, is both a PCI QSA company and a PCI SSC-qualified Software Security Framework assessor company.