SOC 2 vs ISO 27001: which should your startup do first?

This guide is for founders and engineering leads who keep seeing both SOC 2 and ISO 27001 on security questionnaires and need to pick one to start with. By the end you will know what each one actually is, how the audits differ, which buyers ask for which, how much of the work is shared, and how to sequence them so you only build your security program once.

On this page

• What each one is

• SOC 2 vs ISO 27001 at a glance

• Which one your buyers will ask for

• How the audits and timelines work

• How much of the work overlaps

• If you need both, the order that saves work

• How NexusVoid helps

What each one is

SOC 2

SOC 2 is a report, not a certificate. A licensed CPA firm examines your system and gives an opinion on whether your controls meet the Trust Services Criteria published by the AICPA. Security is always in scope; Availability, Confidentiality, Processing Integrity and Privacy are optional.

A Type I report tests control design on a single date. A Type II report tests whether the controls operated effectively over a period, usually 3 to 12 months. Enterprise buyers mostly want Type II. SOC 2 is flexible: you describe your own controls, and the auditor tests what you described.

ISO 27001

ISO/IEC 27001 is an international standard for an information security management system, or ISMS: the policies, roles, risk process and review cycle you use to manage security. The current version is ISO/IEC 27001:2022. The transition period for certificates issued against the older 2013 version ended on 31 October 2025, so any certificate you get now, or ask a vendor for, should cite 2022.

The standard has two parts. Clauses 4 to 10 are mandatory and describe the management system: context and scope, leadership, planning and risk, support, operation, performance evaluation and improvement. Annex A lists 93 reference controls in four themes: 37 organizational, 8 people, 14 physical and 34 technological. You do not have to implement every Annex A control, but you must justify each inclusion or exclusion in a Statement of Applicability.

SOC 2 vs ISO 27001 at a glance

The biggest practical difference is what the auditor is looking at. A SOC 2 auditor reads your system description and tests whether the controls you listed actually ran. An ISO 27001 auditor checks that you run a working management system: that you assessed risk, chose controls because of it, measured how they perform, audited yourself and reviewed the results with leadership.

The second difference is what the buyer receives. A SOC 2 Type II report is long and detailed, and a security reviewer can see exactly which controls were tested and where the exceptions were. An ISO 27001 certificate is one page that states your scope. Careful buyers will also ask for your Statement of Applicability, and sometimes your latest audit summary, to see what sits behind it.

Which one your buyers will ask for

There is no rule here, only patterns. Ask your top prospects before you commit, because one large deal can settle the question.

• US buyers, especially mid-market and enterprise software companies, usually ask for SOC 2 Type II by name.

• European buyers more often ask for ISO 27001, and GDPR-minded procurement teams are used to it.

• India-based enterprises, banks and many government-linked buyers commonly ask for ISO 27001.

• Global enterprises often accept either, and sometimes want both.

• If you sell to a mix, the region of your largest near-term deals should decide which comes first.

Neither one is a legal requirement in itself. They are market requirements set by procurement. Neither replaces privacy law such as GDPR or India’s DPDP Act, sector rules such as HIPAA, or payment rules such as PCI DSS, though the controls you build for SOC 2 or ISO 27001 cover a lot of the security ground those also expect.

How the audits and timelines work

SOC 2

1. Readiness: set scope, write policies, close gaps, connect evidence sources. Often 4 to 12 weeks for a small cloud team.

2. Optional Type I: design tested as of one date.

3. Type II window: 3 to 12 months of controls running, with evidence collected throughout.

4. Fieldwork and report: the auditor samples evidence and issues the report a few weeks after the window closes.

5. Repeat each year, ideally with back-to-back windows so there is no gap in coverage.

ISO 27001

1. Build the ISMS: scope, information security policy, risk assessment method, risk treatment plan, Statement of Applicability, objectives and the Annex A controls you selected.

2. Run it: operate the controls, then complete at least one internal audit and one management review before the certification audit.

3. Stage 1 audit: the certification body reviews your documentation and readiness.

4. Stage 2 audit: they test whether the ISMS and controls are actually working. A successful Stage 2 leads to the certificate.

5. Surveillance audits in years one and two, then a recertification audit in year three.

For a startup with reasonable engineering hygiene, either one commonly takes a few months to get audit-ready. ISO 27001 often needs more up-front documentation because of the management system. A SOC 2 Type II takes longer on the calendar because of the observation window. Auditor and certification body fees vary widely with scope, headcount and firm, so get several quotes.

How much of the work overlaps

Most of it. The AICPA publishes a mapping between the Trust Services Criteria and ISO 27001, and both frameworks are describing the same good practice in different words. The shared core looks like this:

• Access control: least privilege, MFA, joiner and leaver processes, periodic access reviews.

• Change management: code review, branch protection, separated environments, controlled deploys.

• Vulnerability management: scanning code, dependencies and cloud, patching on a timeline, regular pentests.

• Logging, monitoring and incident response: alerting, an incident plan and records of real or practiced incidents.

• Vendor risk: a list of suppliers that touch your data and evidence that you reviewed them.

• People: signed policies, onboarding checks and security awareness training.

• Business continuity: backups, restore tests and a recovery plan.

What is genuinely different is mostly on the ISO side: the formal risk assessment and treatment process, the Statement of Applicability, internal audits, management review, and documented security objectives you measure. Going the other way, SOC 2 needs a written system description and a Type II window of evidence that ISO does not ask for in the same form.

If you need both, the order that saves work

If you will likely need both within a year or two, which is common for startups that sell internationally, the sequence matters less than how you build the first one.

1. Start from one control set, not one framework. Write each control once, in your own words, and map it to both SOC 2 criteria and ISO 27001 Annex A.

2. Run a real risk assessment early, even for SOC 2. ISO requires one, SOC 2 expects one, and it tells you which controls matter.

3. Collect evidence continuously from your systems. The same access review export or pull request record then counts toward both audits.

4. Do the first audit your buyers need now.

5. Add the ISO-specific pieces, or the SOC 2 system description and window, as the second project. It should be weeks of focused work, not a restart.

The mistake to avoid is building SOC 2 in one tool or spreadsheet with its own policies and evidence, then starting a separate ISO 27001 project a year later. That doubles the evidence collection forever, and the two programs drift apart.

How NexusVoid helps

NexusVoid runs your security program for you, like an autonomous CISO, and compliance comes out as a by-product. If you have no CISO, it acts as one. If you have a CISO or vCISO, it automates most of their routine work.

Aegis keeps one shared control set across SOC 2, ISO 27001, DPDP, GDPR, HIPAA, PCI DSS and other frameworks, so one control and its evidence count toward every framework it satisfies. It tailors policies to your company, collects evidence automatically from your cloud, GitHub, identity provider and devices, keeps the risk register and vendor list ISO 27001 expects, answers security questionnaires from your evidence, and produces auditor-ready exports.

Argus and Striker do the security work both audits test: finding issues in code, dependencies, cloud and secrets, opening fixes as pull requests, retesting when fixes merge, and running pentests with a report in under 60 minutes. Auditors and certification bodies stay independent. NexusVoid gets you ready and keeps you ready.

Frequently asked questions

Is ISO 27001 harder than SOC 2?

Different, rather than harder. ISO 27001 asks for more up-front structure: a risk process, a Statement of Applicability, internal audits and management review. SOC 2 Type II asks for proof that controls ran over months, which takes longer on the calendar. Teams that already work in a disciplined way usually find the technical controls are the same for both.

Will a European customer accept a SOC 2 report?

Often, yes, especially software and technology buyers who are used to US vendors. Some procurement teams, particularly in regulated sectors or the public sector, specifically require ISO 27001 certification. The quickest way to know is to ask before you start, and to check the wording in your prospect’s security questionnaire or contract.

Can one audit firm do both?

Some firms offer both, through a CPA practice for SOC 2 and an accredited certification body for ISO 27001. Running the audits together can reduce duplicated interviews and evidence requests. Check that the ISO side is accredited, and that the SOC 2 side is a licensed CPA firm, before you sign.

Do we need ISO 27001:2022 or is 2013 still fine?

Use 2022. The transition period for 2013 certificates ended on 31 October 2025, so certificates against the old version are no longer valid. The 2022 version reorganized Annex A into 93 controls in four themes and added new ones, such as threat intelligence and information security for cloud services.

What does a buyer actually check on an ISO 27001 certificate?

The scope statement first: whether the product and locations they care about are covered. Then the version, the issue and expiry dates, and whether the certification body is accredited. Careful buyers also ask for your Statement of Applicability to see which Annex A controls you included and why.

If you are deciding between SOC 2 and ISO 27001, or need both and want to build it once, talk to a founder. Book a call at /contact and we will look at your buyers and your current setup with you.