About
Security leaders who've done the work.
We're a network of senior security, IT, and compliance professionals who've spent 15+ years in the trenches - building programs, running audits, responding to incidents, and defending systems across industries. When you engage 543HQ, you get practitioners, not generalists.
Who we are
543HQ is built around a tight network of security and IT leaders who've led programs at companies of every size and shape - from pre-revenue startups building their first security policy, to mid-market companies chasing their first SOC 2, to global enterprises managing complex, multi-framework compliance across multiple countries.
We bring team members in strategically, based on what the engagement actually requires. Need a PCI DSS expert who's managed live QSA audits with Deloitte and PwC? We have that. Need someone who's built a HITRUST program at a digital health company from scratch? That too. The right practitioner for the specific problem, not the nearest available person.
Our work spans the full security lifecycle: standing up programs where none exist, maturing programs that have outgrown their original design, and operating as an ongoing security leadership function for companies that don't need a full-time hire.
We're also practitioners in AI-driven security operations - not as a pitch, but as something we've built and deployed in production. Agentic alert triage, automated compliance evidence gathering, AI governance frameworks. It's part of how we work, and it's available to our clients.
Industries we've worked in
Deep operational experience across verticals - not surface-level familiarity.
Fintech & Payments
Security programs for platforms processing billions in transactions annually. PCI DSS 4.0 compliance, SOC 2 Type II, fraud detection, and multi-brand vulnerability management. Audited by Deloitte and PwC.
Digital Health & Healthcare IT
HIPAA compliance, HITRUST r2 certification, and cloud security architecture for patient data platforms. Active members of the Health Information Sharing and Analysis Center (H-ISAC).
Global Retail
Security operations at enterprise scale across 500+ retail locations spanning the US, Canada, and UK. SOC buildout, threat detection, incident response, and PCI DSS compliance.
SaaS & Software
Security programs built from zero at high-growth software companies, through M&A, IPO prep, and public company scale. ISO 27001, SOC 2, AppSec programs, and developer security training.
Legal Tech
Security and compliance for platforms handling sensitive legal matter data. Data classification, access control, and compliance frameworks appropriate for client confidentiality obligations.
What we've built
A sample of the programs, systems, and capabilities our team has delivered across engagements.
Security Program Design & Buildout
- - Security programs built from zero at startups and growth-stage companies
- - SOC design, staffing, playbooks, and ongoing operations
- - Security policy and standards libraries aligned to NIST, ISO, and PCI
- - M&A security due diligence and post-acquisition program integration
- - Vendor and third-party risk management programs
Cloud & Infrastructure Security
- - Zero Trust architectures on AWS and Azure
- - AWS security controls: GuardDuty, Inspector, WAF, Macie, CloudTrail
- - Microsoft security stack: Defender XDR, Entra ID, Purview, Intune
- - Cloud security posture management (CSPM)
- - Network segmentation, Cloudflare, and identity-first access models
Compliance & Audit Execution
- - PCI DSS 4.0 - QSA management, SAQ-D, audit prep (Deloitte, PwC, Cognisys)
- - SOC 2 Type I & II - readiness, evidence automation, and audit management
- - HIPAA / HITECH compliance and Security Officer engagements
- - HITRUST r2 certification management
- - ISO 27001, ISO 42001, NIST CSF, and NIST 800-53
Threat Detection & Response
- - SIEM deployment and tuning: CrowdStrike NG-SIEM, Splunk, Datadog
- - EDR: CrowdStrike Falcon across enterprise and cloud environments
- - Incident response program design and live incident management
- - Threat intelligence: H-ISAC, RH-ISAC memberships and intel sharing
- - MSSP integration and 24/7 monitoring architecture
Application & Product Security
- - AppSec programs with SAST/DAST: Veracode, Sonarqube, OWASP ZAP
- - Snyk-based open source vulnerability management for engineering teams
- - Secure SDLC, code review processes, and developer security training
- - Supply chain security monitoring (npm/PyPI) with automated triage
- - AI and LLM security reviews aligned to OWASP GenAI Top Ten
AI Security & Automation
- - AI governance frameworks aligned to ISO 42001 and OWASP GenAI Top Ten
- - Production agentic security pipelines for alert triage and vuln outreach
- - Automated compliance evidence gathering at scale
- - MCP server security reviews and AI tool risk assessments
- - Security automation using Python, n8n, and custom tooling
Tools & frameworks
Technologies our team has deployed in production - not just evaluated.
Why 543HQ
Senior-led, every engagement
Every project is led and delivered by a practitioner with 15+ years of real-world experience. Not a coordinator, not a junior analyst following a playbook. Senior expertise on every call and every deliverable.
Right-sized for where you are
We've worked with companies at every inflection point - pre-revenue startups building their first policy, growth-stage teams chasing SOC 2, and global enterprises managing multi-framework compliance. We scope to your actual situation, not a standard package.
Implementation, not advice
We've built the programs, written the policies, configured the tools, and walked through the audits. We're not handing you a report. We're building alongside you and accountable to the outcomes.
AI-forward by default
We've deployed production agentic security systems - not demos, real workflows running at scale. AI-assisted triage, automated compliance evidence, security governance for AI adoption. We bring this thinking to every engagement.
Let's talk about what you're building.
Start with a free 30-minute call. No commitment, no pitch deck.
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