Custom Software Development & Penetration Testing in Charleston, SC

QUANT LAB USA pairs custom software engineering with hands-on penetration testing rooted in the MITRE ATT&CK framework. We are a Macon, Georgia firm serving Charleston remote-first across the same Eastern Time zone, with travel into Charleston, Berkeley, and Dorchester counties for major builds and on-site network work. Charleston operators typically need the same things: multi-tenant SaaS that scales cleanly, booking and billing that holds up in peak season, and a pen test report that unblocks enterprise procurement and SOC 2.

Charleston's software demand spans tech, tourism, and industry. The Charleston Digital Corridor catalyzed a Silicon Harbor startup scene — Blackbaud on Daniel Island is the anchor, and a long tail of SaaS, fintech, and software companies has grown around it. The Port of Charleston is one of the busiest container ports on the East Coast, and the logistics base feeding it needs dispatch and inventory tooling. Boeing South Carolina in North Charleston anchors an aerospace manufacturing cluster with its own supplier software needs. And the Lowcountry tourism economy — historic downtown, Mount Pleasant, and the beaches — runs on reservations, ticketing, and guest-experience platforms. It is a compact metro with a genuinely diverse set of software needs and rising security expectations from enterprise buyers.

Most Charleston shops are either boutique design studios or staff-augmentation bodies. We sit in the middle: founder-led delivery with enterprise-grade engineering practices and in-house offensive security. No offshore handoff and no junior outsourcing — William Beltz scopes, builds, and ships. That matters when a Silicon Harbor SaaS needs both a clean codebase and a pen test report that closes an enterprise deal, or when a tourism operator needs a booking flow that does not buckle on a festival weekend.

Charleston buyers want senior accountability without consultancy overhead. Our model delivers exactly that: every engagement is scoped, built, and shipped by the founder, on a fixed-scope and fixed-price proposal with a written acceptance milestone — not open-ended time-and-materials billing. Our pen testing is in-house capability, not a subcontracted line item: Active Directory abuse paths, lateral movement, ADCS certificate abuse, Kerberoasting, wireless attacks, and web application exploitation, with every finding mapped to a MITRE ATT&CK technique ID. And every line of software we ship is reviewed against the same threat models we use on offensive engagements.

We run full Eastern Time overlap from Macon, which keeps standups and reviews on Charleston's clock. Most kickoffs are a video call followed by a single on-site afternoon — typically downtown, on Daniel Island, in Mount Pleasant, or in North Charleston — to walk the workflow we are replacing. From there, build cycles run weekly: every Friday you get a deployed staging URL, written notes on what changed, and the next-week plan. Pen testing engagements run from secure remote infrastructure with strict source-IP allowlisting and authenticated VPN tunnels for internal scope, and we travel to Charleston for sensitive scoping and for internal tests requiring on-site network access. Reports ship in two formats: a technical deliverable with reproduction steps for the security team, and a board-readable executive summary with a prioritized remediation roadmap. Most Charleston engagements close inside 4–6 weeks from kickoff to final report.