Most startups treat GDPR and ISO 27001 as two projects: a lawyer owns one, an engineer owns the other, and the same questions get answered twice in different documents. But the two frameworks share a spine, and running them on one system roughly halves the combined effort.
Where they overlap
GDPR's Article 32 requires "appropriate technical and organisational measures" for personal data, which is, functionally, a description of an ISMS. Access control, encryption, incident response, supplier management, training: every one of these is simultaneously an Annex A control and a GDPR measure. Implement once, evidence once, satisfy both.
What GDPR adds on top
- Records of processing (Article 30): what personal data you process, why, and where it flows. On a shared platform this is a view over your registry, not a separate spreadsheet.
- DPAs and subprocessors: agreements with every vendor touching personal data, and a public subprocessor list, which your trust center can publish automatically from the same vendor registry.
- Data subject requests: workflows for access, deletion, and portability requests, with deadlines and evidence of completion.
- Lawful bases and privacy notices: the legal layer proper, drafted once, kept current alongside your policies.
ISO 27001 proves you run security as a system. GDPR demands security as a system for personal data. The overlap isn't a coincidence, it's the same discipline with two audiences.
Why one system beats two projects
Beyond the effort saved, coherence is the real prize. When the DPA tracker, the risk register, and the incident process live in one place, a vendor breach triggers one workflow that satisfies both the auditor and the regulator. When they're separate projects, the same event produces two inconsistent paper trails, the worst possible position in a regulatory inquiry.
In practice
Certixa's plans run GDPR on the same ISMS objects as ISO 27001: shared controls satisfy both frameworks at once, records of processing generate from the registry, and subprocessor lists publish to your trust center. One system, both boxes, which is also the answer European buyers actually want to hear in security questionnaires.