Vendor security questionnaires are how buyers translate your product into their risk language. They show up as SIG Lite, CAIQ, custom Excel, or a portal with 12 tabs. The wording changes. The themes don’t: access, encryption, logging, SDLC, incident response, subprocessors, backups.
The failure mode isn’t “we don’t know.” It’s rewriting last year’s answers under deal pressure until someone invents a confident yes. This guide is the anti-version of that — fill the sheet, cite the proof, leave gaps honest.
What a vendor security questionnaire actually is
It’s not a quiz about your SOC 2 report. It’s a checklist of operational claims the buyer wants on the record today: who can reach production, how you encrypt customer data, how fast you notify on incidents, which vendors touch content. Your report helps. It rarely replaces the form.
For the broader landscape (formats, buyers, when to push back), see security questionnaires, explained. For SOC 2–shaped asks, use how to survive SOC 2 vendor questionnaires.
The five-step fill workflow
1. Intake the buyer’s structure
Keep their columns, IDs, and wording. Do not rebuild the sheet in your own template first — you’ll spend half a day remapping later. Export or download whatever they sent (XLSX, CSV, portal dump).
2. Theme-map before you answer
Tag each row to a control theme (access, encryption, IR, vendors…). Ten minutes of mapping saves hours of hunting the same policy section twice. Framework sheets (SIG / CAIQ) already hint at themes; custom Excel is messier but still collapses to the same pile.
3. Draft from evidence — cite or flag
- If you have a policy section, architecture note, or prior approved answer → draft + citation.
- If you don’t → mark UNVERIFIED (or equivalent). Don’t paper over it with confident prose.
- Never paste secrets into the sheet — cite where the proof lives.
4. Human approve under one owner
One person owns the export. Eng and security can edit rows; the submitter still accounts for every claim. Deal pressure is when invented “yes” cells appear — the UNVERIFIED flag is there to survive that moment.
5. Export and submit yourself
You (or your security lead) submit through the buyer’s portal. Tools should draft and cite — not auto- send or join the sales call.
What to keep reusable between deals
Build an answer bank keyed by theme, not by buyer wording. Canonical claim + evidence pointer + owner + last-verified date. That’s how SIG Lite and CAIQ stop forcing full rewrites — details in the SIG Lite / CAIQ answer bank guide.
The vault underneath matters more than the spreadsheet: versioned policies, architecture summaries, report excerpts, runbooks. See evidence vault for vendor security reviews.
Common traps (and the fix)
- Copy-paste from last year’s portal export → refresh the cited source first, then the row.
- Treating SOC 2 as a free pass → bring report + current operational answers.
- Letting sales fill blank cells at 11pm → UNVERIFIED stays visible until evidence lands.
- Rewriting every custom Excel from scratch → theme map once; reuse the claim layer.
Where Trustfill helps
Trustfill drafts cited answers from your evidence vault for SIG / CAIQ / Excel questionnaires. Gaps stay UNVERIFIED. You approve, then export. Self-serve — start with one free questionnaire, or try the sample demo.
Comparing approaches? Manual questionnaires vs Trustfill. Want the automation framing? Security questionnaire automation that doesn’t invent answers.