JS Jared Smith Founder & Engineering Leader
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Topic guide

Security for startups

Pre-Series-A security gets scoped wrong three ways: founders treat SOC 2 as a security project (it isn't), they hire a CISO before they need one (a $300K mistake at the wrong stage), and they bolt classic appsec onto AI-native architectures that need a different stack entirely. Each of the posts below reframes one of those decisions and gives the actual numbers from real engagements.

Read in order if you're starting from scratch — SOC 2 first to anchor the revenue framing, then vCISO math to size the security org, then the AI-native stack to scope the actual work. The engagement-teardown post is for when you've decided the work is needed and want to know what the next 90 days look like in practice. The auth-migration post is for when you've already shipped and need to fix it without forcing every user to re-authenticate. Two later groups pick up where the overview stops: the layer-by-layer posts on prompt injection, agent credentials, and tenant isolation are for teams already shipping agents, and the pair on benchmark claims is for reading a security vendor's 96% before the call rather than after. If you got here searching for a startup security consultant: fractional security leadership is the same work, scoped monthly instead of hourly — the vCISO math post covers what that costs.

The reading order

  1. 1.

    SOC 2 Is a Revenue Tool, Not a Security Tool

    $25–45K total over 90 days. Scope it as a sales project, not a security project. The playbook for unlocking enterprise pipeline before Series A.

    April 27, 2026 4 min read

  2. 2.

    Why Auto-Filled Security Questionnaires Kill AI Deals

    Auto-filling two hundred questionnaire fields reads as risk, not progress — one clarifying question on a live call collapses an answer nobody on your team wrote. SOC 2 answers maybe sixty of those questions and is silent on the dozen the deal actually hinges on: prompt injection, tenant isolation, what each model provider's terms say about retention and training.

    July 7, 2026 13 min read

  3. 3.

    What Cyber Insurance Underwriters Ask AI Startups

    Premiums run roughly $1,500–1,800 a year for $1M in coverage. The application is the exposure: Travelers got its insured's entire policy rescinded after a ransomware claim revealed the MFA attestation wasn't true. ISO issued three generative-AI exclusion endorsements in January 2026 — find that language in your quote.

    July 10, 2026 9 min read

  4. 4.

    vCISO Math for AI Founders: Why 5 Hours a Month Beats a Full-Time Hire

    Full-time CISO costs $200–400K and is over-leveled for pre-Series-A work. Fractional vCISO is $2–4K/month. The graduation criteria are explicit.

    April 6, 2026 9 min read

  5. 5.

    Security Engineer or vCISO? Your First Hire, by Stage

    A $220K security engineer dropped into a 12-person startup invents their own job while the enterprise questionnaire in your pipeline sits untouched. Pre-seed it's hygiene, not a role. Seed is 15–25 real hours a month of decisions, so fractional. The first security engineer earns the seat at Series A, when the work flips from decisions to engineering.

    July 17, 2026 10 min read

  6. 6.

    Shadow AI at a Startup That Can't Buy a CASB

    A CASB is the right tool at 500 employees and the wrong conversation at 12. Three free things instead, inside two weeks: a card-statement-and-SSO-log audit of what's actually connected, a no-blame survey for what isn't, and a one-page data-classification rule. You outgrow it around 25-30 people with no security owner.

    July 22, 2026 9 min read

  7. 7.

    How I'd Run Security at an AI-Native Company in 2026

    The four-layer stack — prompt injection defense, agent credentials, secrets handling, audit logging. None of these come for free in classic appsec.

    April 20, 2026 9 min read

  8. 8.

    Prompt Injection Defense for a 5-Person AI Startup

    EchoLeak (CVE-2025-32711, CVSS 9.3) exfiltrated Microsoft 365 Copilot data zero-click and walked straight past Microsoft's own cross-prompt injection classifier. The deterministic answer is about a week of work, most of it deletion: every tool scoped to the session's user, outputs validated and not just inputs, a human gate on anything state-changing.

    July 3, 2026 9 min read

  9. 9.

    Secrets Management for AI Agents on Small Teams

    GitGuardian counted 28.6 million secrets exposed in public GitHub commits in 2025, over 24,000 of them in MCP configuration files. The model never needs the key: a broker between the model and every side effect, least privilege scoped to the tool rather than the agent, and one kill switch you've actually tested. Includes what not to buy yet.

    July 15, 2026 10 min read

  10. 10.

    Multi-Tenant AI SaaS in Phoenix: Isolation That Holds

    Storage scoped correctly and the retrieval read not — one missing where clause, and top-k similarity returns the nearest chunks from every tenant, with a clean log and a passing test suite. Covers shared versus per-tenant provider keys (OpenAI enforces rate limits at the organization and project level, not per raw API key), one scoped queryable with no unscoped path into it, and the CI test that fails the day someone adds one.

    August 6, 2026 11 min read

  11. 11.

    Detection Got Cheap. Remediation Didn't.

    Microsoft's MDASH harness runs 100+ agents and scored 96% on CyberGym at a 50% cost saving over their current offering — and changes nothing about your capacity to fix what it finds. At 12-40 people the constraints are engineer time and the political cost of blocking a release. Write the three-tier rubric before the next scan runs, give the queue one owner, budget fix capacity at 10% of engineering time.

    July 29, 2026 10 min read

  12. 12.

    What a 96% Security Benchmark Actually Measures

    CyberGym is 1,507 historical bugs already patched in the public record, and the agent is handed the pre-patch codebase plus a textual description of the vulnerability — that's reproduction, not discovery. The evidence worth weighing is the 16 new vulnerabilities in the Windows networking and authentication stack and the held-out driver with 21 injected flaws, all identified with zero false positives. Five questions to ask before the vendor call.

    July 28, 2026 10 min read

  13. 13.

    What 90 Days of a Fractional Security Engagement Actually Looks Like

    The week-by-week composite of a typical 90-day fractional CISO engagement. $32–42K total cost. What graduation looks like at month four.

    May 3, 2026 8 min read

  14. 14.

    Migrating 225K Users from AWS Cognito to Auth0 Without Forcing a Single Logout

    Production identity migration without forcing 100K users to re-authenticate. Hash incompatibility, lazy migration, MFA token handling — the implementation details vendor docs skip.

    March 30, 2026 9 min read

  15. 15.

    Surviving Technical Due Diligence as an AI Founder

    What the investor's technical reviewer opens first, the AI-specific flags that re-price rounds in 2026, and the gaps you should deliberately leave alone.

    June 30, 2026 13 min read

Other topic guides

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  • Engineering leadership Engineering leadership at startup scale — hiring from one engineer to fifteen, rituals that work at small teams, the staff-engineer interview loop.
  • Elixir and the BEAM for AI systems Why language choice matters for AI systems — BEAM concurrency for agents, what Go frameworks cost you, and why Elixir is the language AI writes best.

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