SOC 2 vs ISO 27001: which does a European startup actually need

A prospect asks for your "security certification" and you go looking. Every second guide tells you to get SOC 2. Most of those guides are written from a North American desk, where SOC 2 is the default ask. If you are selling from Europe, the honest answer is usually the other one, and the two are not interchangeable deliverables.

The short answer: the buyer decides, not you

This is not a matter of taste. Which one you need is set by the customer in front of you. North American enterprise buyers overwhelmingly ask for SOC 2. European and international buyers, and most public-sector and regulated procurement, recognise ISO 27001. If a specific deal has named a standard, that is the one to get. If nobody has specified and your pipeline is mostly European, ISO 27001 is the safer default because it is recognised in more places.

What each one actually is

• SOC 2 is an attestation. A licensed CPA firm examines your controls against the Trust Services Criteria and writes a report. A Type I attests the controls are designed correctly at a point in time; a Type II attests they operated effectively across a window, commonly three to twelve months. You refresh the report every year.
• ISO 27001:2022 is a certification. You build a working information security management system (the ISMS), a certification body audits it in two stages (Stage 1 reviews your documentation, Stage 2 tests whether the controls are actually followed), and you get a certificate valid for three years.

That structural difference, a yearly attestation report versus a three-year certificate, is what makes the two feel different to live with, and it is where the cost shapes diverge.

What each costs in year one

The auditor invoice is only one of four lines, and usually not the biggest. Reusing the planning bands the estimator runs on:

• SOC 2 Type II auditor fee: roughly 12,000 to 30,000 dollars.
• ISO 27001:2022 Stage 1 plus Stage 2 audit: roughly 14,000 to 38,000 dollars.
• Compliance-automation tooling: a band from about 7,000 to 30,000 dollars a year depending on headcount and how many frameworks you run.
• Independent penetration test: about 4,000 to 12,000 dollars, expected by auditors and enterprise buyers for either standard.

On top of those sits your own team’s time, writing policies, wiring up logging and assembling evidence, which is typically the single largest line for either framework. So the two land in a broadly similar first-year range, with ISO 27001 often slightly higher because the two-stage audit plus the required management system (with its own mandatory internal audit and management review) add work.

Where the renewal economics diverge

They cost about the same to start and then behave differently. SOC 2 is a report you commission again every year, so year two looks a lot like year one. ISO 27001 front-loads the effort: after the initial certification, years two and three are lighter surveillance audits that sample a subset of controls rather than re-examining the whole ISMS, and a fuller recertification audit comes at the end of the three-year cycle. If you expect to hold a standard for years, ISO 27001’s renewal path is the cheaper one; if you are not sure you will keep it, SOC 2’s pay-as-you-go yearly cadence carries less commitment.

Which one you can show a buyer faster

The two also differ on how quickly you can put proof in a buyer’s hands, which matters when a deal is waiting on it. SOC 2 has a fast point-in-time option: a Type I report attests that your controls are designed correctly on a single date, so once the controls are in place a Type I can be issued within weeks. A common play is to hand a prospect the Type I as a bridge, then run the Type II observation window (a three-month minimum, six is common) in the background and deliver the fuller report later.

ISO 27001 has no point-in-time shortcut. Before a certification body will run the Stage 2 audit, the management system has to be genuinely operating: at least one internal audit and one management review completed, and in practice around three months of records for the auditor to sample, with Stage 2 falling within six months of Stage 1. So the fastest honest ISO deliverable is not a certificate but evidence of progress, a completed Stage 1 or a signed Statement of Applicability. If a single deal needs proof this quarter, that asymmetry can decide it: SOC 2 Type I is the quickest thing you can genuinely put on the table.

What you can show publicly, and what stays under NDA

One more difference decides how each standard shows up in your sales and marketing, not just your audit budget: whether you can display it. A SOC 2 report is a confidential deliverable. It spells out your controls in detail and, in a Type II, any exceptions the auditor found, so it is not something you post on a trust page; a prospect signs an NDA and you hand it over deal by deal. You can show a SOC 2 seal to say the report exists, but the report itself stays private. That adds a small gate to every deal, an NDA before the evidence changes hands.

ISO 27001 works the other way. The outcome is a public one-page certificate you can display on your website and in a pitch, and a buyer can verify it directly with the certification body that issued it (accredited certificates also appear in public registries such as IAF CertSearch). What stays private is the detail behind it: your Statement of Applicability and the ISMS records. So ISO 27001 doubles as a self-serve trust signal anyone can check without asking, while SOC 2 is proof you disclose under NDA. If a visible, verifiable mark on your site is part of what you are buying, that asymmetry is a point for ISO 27001; if your buyers simply want to read the report under NDA, it does not change the decision.

If you might need both, the overlap pays

Plenty of teams selling on both sides of the Atlantic end up needing both. The good news is that the two frameworks share most of their underlying controls, so the evidence you gather for one does most of the work for the other. The estimator reflects this: a combined SOC 2 Type II plus ISO 27001 auditor engagement lands around 22,000 to 55,000 dollars, which sits below the roughly 26,000 to 68,000 you would pay for two separate audits, and one automation platform covers both rather than doubling the tooling bill.

The European trap: ISO 27001 is not GDPR

This one catches European founders often. ISO 27001 is an information security certification; the GDPR is a data-protection law, and they are not the same thing. Holding ISO 27001 helps you demonstrate the "security of processing" that Article 32 of the GDPR requires, and it is strong evidence of good practice, but it does not make you GDPR compliant on its own, and there is no official GDPR certificate you can buy. You still need a lawful basis for processing, data-subject request handling, records of processing and the rest. Treat ISO 27001 as the security half of the story, not the whole of your data-protection obligations.

Pick the standard your buyers actually ask for, budget for all four cost lines rather than just the auditor, and if the answer is "both", lean on the overlap instead of running two projects in parallel.