ISO 27001 and SOC 2 are the two security credentials growing companies get asked for most. They overlap enormously in substance but differ in form, geography, and how buyers perceive them. Here's how to decide which to pursue first, and why you rarely have to choose forever.
The short version
- SOC 2 is an attestation report written by a US CPA firm against the Trust Services Criteria. It's dominant with North American buyers and SaaS procurement.
- ISO 27001 is an international standard you get certified against by an accredited body. It's expected more often by European, UK, and global enterprises and in regulated sectors.
If most of your buyers are US tech companies, start with SOC 2. If you sell into Europe or to large global enterprises, ISO 27001 may open more doors.
How they actually differ
| SOC 2 | ISO 27001 | |
|---|---|---|
| Output | Auditor's report (Type I or II) | Certificate + audit report |
| Who issues it | Licensed CPA firm | Accredited certification body |
| Model | Trust Services Criteria | ISMS + Annex A controls |
| Cadence | Annual report | 3-year cycle with yearly surveillance |
| Recognition | Strong in US | Strong internationally |
They overlap more than they differ
Both frameworks want the same fundamentals: access control and access reviews, encryption, change management, logging and monitoring, vulnerability management, vendor risk, incident response, and governance through policies and management review. ISO 27001 adds a formal Information Security Management System (ISMS), the governance wrapper of scope, risk assessment, objectives, internal audit, and management review, and its own Annex A control set.
Because the underlying controls are largely the same, doing one gets you most of the way to the other. The trick is to implement each control once and map it to every framework it satisfies, rather than running two parallel projects.
A sensible sequence
- Pick the framework your next 12 months of buyers ask for. Revenue beats theory.
- Implement controls once, mapped to both. MFA, access reviews, and logging count toward SOC 2 and ISO 27001 simultaneously.
- Add the second framework as an overlay, not a restart. With a crosswalk, most of your evidence is already collected.
Don't do the work twice
The expensive mistake is treating each framework as its own project with its own spreadsheet of controls and evidence. A crosswalked approach, one control library mapped to many frameworks, means the marginal cost of your second framework is a fraction of the first.
Keel is built around exactly this: apply SOC 2 and ISO 27001 (and PCI DSS, HIPAA, ISO 9001, NIST CSF) and a single control satisfies clauses across all of them. You collect evidence once and watch readiness climb for every framework at the same time.
Start free and see your posture against both frameworks side by side. For a deeper look at SOC 2 itself, read our complete SOC 2 guide for startups.