Every SaaS founder hits this fork: a prospect's security review asks about certifications, and the internet offers two acronyms. The good news is the decision is mostly geographic. The better news is the work overlaps heavily.
What each one is
ISO 27001 is an international standard certifying that you operate an information security management system. An accredited body audits you; you get a certificate valid for three years. It's the default ask across Europe, the UK, and most of the world outside North America.
SOC 2 is a US attestation framework: a CPA firm examines your controls against the Trust Services Criteria and writes a report (Type I at a point in time; Type II over a period, usually 3–12 months). It's the default ask from US enterprise buyers.
The practical differences
- Output: ISO gives a certificate you can publish; SOC 2 gives a confidential report you share under NDA.
- Flexibility: SOC 2 lets you define the control set; ISO's Annex A gives you a catalogue with justified selection, more prescriptive, and therefore more comparable between companies.
- Cadence: ISO runs a three-year cycle with annual surveillance; SOC 2 Type II is effectively an annual re-examination.
- Recognition: a European procurement team may not accept SOC 2 at all; a US one will usually accept ISO 27001 but may still prefer SOC 2.
The decision rule
Certify where your revenue is. European pipeline → ISO 27001 first. US-only pipeline → SOC 2 first. Both → ISO 27001 first, then reuse the ISMS for SOC 2.
The "ISO first" ordering when both matter isn't chauvinism: an ISMS is a durable management system, and the policies, risk register, and evidence it produces map directly onto SOC 2's criteria. Going the other way, bolting a management system onto a SOC 2 control list, is more rework.
The overlap is the point
Access control, incident response, vendor management, backups, training: both frameworks want the same underlying facts. On a platform where one control maps to many frameworks, the second certification is mostly re-reporting existing truth, not new work. The same logic carries GDPR on the same ISMS.
For a European SaaS from €149/month, the order writes itself: ISO 27001 + GDPR now, SOC 2 when the US pipeline demands it.