PrivacyGuard - PII Detection Layer Before Your Prompts Hit Any LLM
Every dev team has that one paranoid colleague who refuses to paste client data into ChatGPT — turns out they are right and everyone else is wrong. PrivacyGuard sits between your team and any LLM, scans outbound prompts for PII and sensitive data in real-time, and optionally reroutes flagged prompts to a self-hosted Ollama instance. Ship this to one fintech or law-adjacent SaaS team and charge $500/month before lunch.
Difficulty
intermediate
Category
Developer Tools
Market Demand
Very High
Revenue Score
8/10
Platform
VS Code Extension
Vibe Code Friendly
No
Hackathon Score
🏆 8/10
Validated by Real Pain
— seeded from real developer complaints
Teams regularly paste sensitive client data into public LLM interfaces because there is no lightweight interception layer — the workaround is either avoiding AI tools entirely or manually sanitizing every prompt, both of which are slow and unreliable. Multiple threads confirm willingness to pay for a local-first solution that generates compliance audit trails.
What is it?
Developers and teams at mid-market companies regularly paste client emails, contract snippets, API keys, and financial data directly into ChatGPT or Claude without any guardrails — a compliance nightmare that HR and security teams are only now waking up to. PrivacyGuard is a VS Code extension plus a lightweight Slack bot that intercepts prompts before they leave the machine, runs a local spaCy NER scan plus regex patterns to detect SSNs, emails, credit card numbers, API keys, and named entities, then either redacts them automatically or hard-blocks the request with an audit log entry. For flagged prompts, users can toggle routing to a locally running Ollama model instead. The audit trail and team-level dashboard give compliance officers the visibility they desperately need. Why 100% buildable right now: the VS Code extension API is mature, spaCy NER runs locally in milliseconds with no external calls, Ollama has a stable REST API, and Supabase handles audit logs trivially — this entire stack existed and was stable as of early 2026.
Why now?
The March 2026 wave of enterprise AI adoption has put PII-in-LLM on every SOC 2 auditor checklist, and Ollama hitting 1M+ pulls makes local LLM rerouting a credible fallback for the first time — this exact combination was not viable 18 months ago.
- ▸Real-time PII detection using spaCy NER plus regex patterns for SSNs, emails, API keys, and credit card numbers before any LLM call.
- ▸One-click Ollama rerouting so flagged prompts stay entirely on the developer's machine with zero data leaving the network.
- ▸Team audit log dashboard showing who sent what, what was flagged, and what action was taken, exportable as CSV.
- ▸Slack bot variant that monitors any Slack-to-LLM workflow and posts a warning before the message is forwarded to an external API.
Target Audience
Security-conscious dev teams at mid-market fintech, legal SaaS, and healthcare-adjacent software companies — roughly 50,000 such teams in North America.
Example Use Case
A five-person dev team at a legal SaaS company installs PrivacyGuard, it catches a developer pasting a client NDA excerpt into Claude, redacts the named parties automatically, routes the cleaned prompt, and logs the event — the CTO shows the audit report to their SOC 2 auditor two weeks later.
User Stories
- ▸As a CTO at a 20-person fintech startup, I want to see an audit log of every LLM prompt my team sends, so that I can show our SOC 2 auditor we have data handling controls in place.
- ▸As a developer, I want PII auto-redacted from my prompts before they leave my machine, so that I never accidentally expose client data to an external API.
- ▸As a security lead, I want to configure a blocklist of sensitive entity types specific to our domain, so that compliance rules match our internal data policy.
Acceptance Criteria
PII Detection: done when a prompt containing a test SSN is flagged and redacted before reaching any LLM API. Ollama Rerouting: done when toggling the setting routes the cleaned prompt to localhost:11434 and returns a valid response. Audit Dashboard: done when team admin can view all scan events filtered by user and date exported as CSV. Stripe Billing: done when team plan upgrade gates the audit export feature and webhook correctly updates the team record.
Is it worth building?
$500/month per team × 10 teams = $5,000 MRR at month 3. $500/month × 40 teams = $20,000 MRR at month 8. Math assumes 2% conversion from cold outreach to fintech Slack communities and direct email.
Unit Economics
CAC: $50 via direct LinkedIn outreach at 5% conversion on 20 emails per customer. LTV: $6,000 (12 months at $500/month average team size). Payback: 1 month. Gross margin: 92%.
Business Model
SaaS subscription per team seat
Monetization Path
Free solo tier (100 scans/day) converts to paid team plan at 15% when audit logs and Ollama routing are gated.
Revenue Timeline
First dollar: week 3 via beta team upgrade. $1k MRR: month 2 with 2 paying teams. $5k MRR: month 5 with 10 teams. $10k MRR: month 9 with 20 teams.
Estimated Monthly Cost
Vercel: $20, Supabase: $25, Stripe fees on $5k MRR: ~$175, spaCy model hosting is local (zero cost). Total: ~$220/month at $5k MRR scale.
Profit Potential
Full-time viable at $8k–$20k MRR with 16–40 paying teams.
Scalability
High — add JetBrains plugin, browser extension for ChatGPT web, and enterprise SSO for larger teams.
Success Metrics
Week 1: 50 extension installs. Week 3: 5 paid team trials. Month 2: 10 paying teams at $500/month, 80% retention.
Launch & Validation Plan
Post in r/netsec and r/devops asking if teams have PII-in-LLM policies, DM 20 CTOs of 10–50 person fintech startups on LinkedIn offering free 30-day team trial in exchange for a 20-minute feedback call.
Customer Acquisition Strategy
First customer: identify 20 Series-A fintech startups on Crunchbase, email the CTO directly with a subject line referencing their SOC 2 status and offer a free 30-day team install with a live audit report. Broader channels: r/netsec, r/devops, HackerNews Show HN, direct LinkedIn outreach to security-conscious CTOs, and partnership with Ollama community Discord.
What's the competition?
Competition Level
Low
Similar Products
Nightfall DLP requires cloud API calls and enterprise contracts. Microsoft Purview is overkill for startups. Rebuff focuses on prompt injection not PII — none offer a local-first VS Code extension with Ollama fallback routing.
Competitive Advantage
Runs entirely locally with no data sent to any cloud service during the scan phase — competitors like Nightfall require cloud API calls which defeats the purpose for paranoid teams.
Regulatory Risks
GDPR compliance required if storing EU user audit logs — implement data deletion endpoint and document retention policy. Low risk overall since data processing is local.
What's the roadmap?
Feature Roadmap
V1 (launch): VS Code extension, local spaCy scanner, audit log dashboard, Ollama rerouting toggle. V2 (month 2-3): Slack bot variant, custom entity blocklist builder, CSV export. V3 (month 4+): JetBrains plugin, SSO, Jira compliance report integration.
Milestone Plan
Phase 1 (Week 1-2): VS Code extension intercepts prompts and logs PII flags locally — done when spaCy catches 10 test PII patterns accurately. Phase 2 (Week 3-4): Supabase audit log, Next.js dashboard, Stripe billing live — done when first beta team pays. Phase 3 (Month 2): Ollama rerouting, team invite flow, Slack bot — done when 5 teams are active.
How do you build it?
Tech Stack
VS Code Extension API, spaCy NER (local), Ollama REST API, Next.js dashboard, Supabase for audit logs, Stripe — build backend logic with Cursor, dashboard UI with Lovable, extension scaffold with Cursor.
Suggested Frameworks
spaCy, FastAPI, LangChain
Time to Ship
3 weeks
Required Skills
VS Code extension basics, spaCy NER integration, Supabase auth and RLS, Stripe billing.
Resources
VS Code Extension API docs, spaCy quickstart, Ollama REST API docs, Supabase quickstart.
MVP Scope
VS Code extension (extension/src/), local spaCy FastAPI microservice (api/scanner.py), Supabase audit log schema (supabase/migrations/), Next.js dashboard (app/dashboard/), Stripe webhook handler (app/api/stripe/), Ollama rerouting toggle (extension/src/router.ts), team invite flow (app/team/), landing page (app/page.tsx).
Core User Journey
Install extension -> connect team workspace -> first PII flag caught and logged in under 60 seconds -> CTO shares audit report -> team upgrades to paid.
Architecture Pattern
Dev types prompt in VS Code -> extension intercepts -> local FastAPI spaCy scanner runs -> if clean, pass to LLM API -> if flagged, redact + log to Supabase + optionally reroute to Ollama -> audit event stored -> dashboard reads Supabase -> Stripe gates team features.
Data Model
Team has many Users. User has many ScanEvents. ScanEvent has one PIIReport (entity types found, action taken, timestamp). Team has one BillingSubscription.
Integration Points
spaCy for local NER scanning, Ollama REST API for local LLM rerouting, Supabase for audit log storage and auth, Stripe for team billing, VS Code Extension API for editor integration, Resend for team invite emails.
V1 Scope Boundaries
V1 excludes: JetBrains plugin, browser extension, custom regex rule builder, SSO, mobile app, white-label.
Success Definition
A paying team's security lead finds the audit dashboard themselves, exports a compliance report, and renews the subscription without any founder involvement.
Challenges
The hardest non-technical problem is convincing individual developers to install a tool that feels like surveillance — positioning must emphasize protection of the dev, not monitoring by the employer. Distribution inside companies requires a champion (usually a CTO or security lead), not a bottoms-up viral loop.
Avoid These Pitfalls
Do not build the Slack bot before the VS Code extension is validated — split focus kills the MVP. Do not gate the free tier so hard that devs never experience the value. Finding your first 10 paying teams will take longer than building the product — budget 3x more time for cold outreach than development.
Security Requirements
Auth: Supabase Auth with Google OAuth and magic link. RLS enabled on audit_events and team_members tables scoped to team_id. Rate limiting: 200 req/min per team via Vercel middleware. Input validation on all API routes. GDPR: data deletion endpoint at DELETE /api/team/data, 90-day audit log retention default.
Infrastructure Plan
Hosting: Vercel for Next.js dashboard and API routes. Database: Supabase Postgres with RLS. Storage: none required in V1. CI/CD: GitHub Actions with Vercel preview deploys. Environments: local dev, Vercel preview per PR, Vercel prod. Monitoring: Sentry for errors, Vercel Analytics. Infrastructure cost: ~$45/month.
Performance Targets
Expected load at launch: 200 DAU, 5,000 scans/day. spaCy scan target: under 50ms locally. Dashboard API response: under 300ms. Page load: under 1.5s LCP. Caching: CDN for static assets, Supabase connection pooling.
Go-Live Checklist
- ☐Security audit on RLS policies complete
- ☐Stripe checkout tested end-to-end
- ☐Sentry error tracking live
- ☐Vercel Analytics dashboard configured
- ☐Custom domain with SSL active
- ☐Privacy policy and data retention policy published
- ☐5 beta teams signed off on audit log accuracy
- ☐Rollback plan: revert to previous Vercel deployment
- ☐ProductHunt and HN Show HN launch posts drafted.
How to build it, step by step
1. Scaffold VS Code extension with yo code generator and TypeScript template. 2. Build local FastAPI endpoint with spaCy en_core_web_sm model for NER plus regex for SSNs and API keys. 3. Wire extension to intercept GitHub Copilot Chat and Claude VS Code extension outbound calls via extension API hooks. 4. Set up Supabase project with audit_events table and RLS policies. 5. Build Next.js dashboard with Supabase auth showing scan history per team. 6. Add Ollama rerouting toggle in extension settings that calls localhost:11434. 7. Integrate Stripe for team subscription with webhook updating team.plan in Supabase. 8. Build team invite flow with Resend email and Supabase team_members join table. 9. Write landing page with Lovable emphasizing SOC 2 and compliance angle. 10. Deploy dashboard to Vercel, publish extension to VS Code Marketplace.
Generated
March 31, 2026
Model
claude-sonnet-4-6