FREELANCE • FULL STACK • DEVOPS • SECURITY-MINDED

I build high-impact digital systems that scale, convert, and stay secure.

I help businesses ship client portals, automate operations, and launch polished websites that actually drive results. Built with production-ready architecture and a security-first mindset.

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Duncan Murchison ● Available for Freelance

Duncan Murchison

Full Stack Engineer • DevOps • Security Playbooks

Full Stack Development

Build robust apps and portals with clean UX and dependable architecture.

DevOps & Automation

CI/CD, deployment workflows, infrastructure scripting, and reliability improvements.

Security Hardening

Security-first patterns, playbook-driven checks, and practical vulnerability reduction.

  • JavaScript
  • Python
  • Ruby
  • Java
  • C++
  • Node.js
  • Rails
  • Flask
  • React
  • MySQL
  • PostgreSQL
  • MongoDB
  • Docker
  • Kubernetes
  • NGINX
  • Postman

FEATURED WORK

Selected work, down to the stack

Two production systems in depth, then the rest. Every stack below comes from the project's own code, and every security practice cites the published standard it follows.

Wholesale Hub product catalog in the live demo

Multi-tenant SaaS · B2B ordering

Wholesale Hub

A wholesale ordering platform for businesses that are done with spreadsheets and phone orders. Customers browse a live catalog and order on their own; the business gets real-time orders, invoicing, shipment tracking and backorder management.

Live tenant
NexGen Truck & Trailer Parts
Tenancy
Silo: every client gets its own stack, database and Cloudflare Tunnel
Payments
Invoices built in; each client can connect their own Stripe account so customers pay online, or keep collecting payment their own way
Releases
The demo tenant is the canary; every rollout reaches it first
Try the live demo ↗ NexGen storefront ↗

Stack

Frontend
  • React + TypeScriptTyped UI components
  • ViteBuilds and dev server
  • TanStack QueryServer state and caching
  • ZodForm schemas mirror the API
Backend
  • FlaskREST API
  • SQLAlchemyORM, expand/contract migrations
  • GunicornProduction app server
  • StripeOptional billing, per client
  • EasyPostShipping labels and tracking
  • RadarVerified addresses, so orders ship
Data
  • PostgreSQLA database per tenant
  • RedisRate-limit store
  • Cloudflare R2Images and PDFs
Infra
  • DockerOne image for every tenant
  • NGINXReverse proxy
  • DigitalOceanDroplet hosting
  • Cloudflare TunnelNo open ports on the server

How tenants stay apart

Silo tenancy One signed image per commit runs in two separate tenant stacks, NexGen and the demo canary. Each stack has its own Cloudflare Tunnel, app, and Postgres and Redis. One image per commit built once · scanned · signed NexGen (live) Demo (canary) Cloudflare Tunnel Cloudflare Tunnel Flask API + React Flask API + React Postgres + Redis Postgres + Redis
Same image, separate everything else. A tenant's data, network path and backups never share infrastructure with another tenant.
  • Tenant isolation is a required CI check: nothing merges if one tenant's stack can reach another's
  • Turnstile on every public formASVS 2.4.1
  • Argon2id password hashing; breached and common passwords rejectedASVS 11.4.2 · NIST 800-63B
  • Dependencies gated by OSV-Scanner, secrets by TruffleHogSSDF RV.1.1 · ASVS 13.3.1
  • One image built per commit, scanned, signed with cosign, deployed by digestSLSA v1.2
  • Backups per tenant, with restores tested per tenant
Computer Anything home page

Business site + client portal

Computer Anything

My company's own platform: the public site plus a client portal with Stripe billing. It's where my CI/CD standard runs end to end, from the first pull request to a signed image in production.

Environments
Staging and production, running the same images
Payments
Stripe Elements: card details never touch the server
Visit computeranything.dev ↗

Stack

Frontend
  • React + TypeScriptTyped UI components
  • ViteBuilds and dev server
  • TanStack QueryServer state and caching
  • ZodForm schemas mirror the API
Backend
  • FlaskREST API
  • SQLAlchemyORM and migrations
  • GunicornProduction app server
  • StripeBilling and card payments
Data
  • PostgreSQLPrimary database
  • RedisRate-limit store
  • Cloudflare R2Images and PDFs
Infra
  • DockerStaging and production stacks
  • NGINXReverse proxy
  • DigitalOceanDroplet hosting
  • Cloudflare TunnelNo open ports on the server

From pull request to production

  1. Pull requestTests, lint and a type-checked frontend build
  2. Security scanTruffleHog for secrets; npm audit and Trivy for dependencies
  3. Build onceOne image per commit, pushed by digest
  4. Signcosign signs every build from main
  5. DeployManual, to a protected production environment
  6. WatchDaily scans of what's running, scheduled backups, uptime monitoring
Computer Anything Blog home page

Full-stack blog

Computer Anything Blog

Markdown posts with tags, votes and comments. Accounts are protected by Turnstile, and email goes out through Resend.

  • Flask
  • React
  • PostgreSQL
  • Redis
  • Resend
  • Cloudflare
Visit the blog ↗
API Looter catalog of public APIs

Open source

API Looter

A catalog of public APIs you can try from the browser. Server-rendered with Flask and Jinja, rate-limited with Redis, and scanned with CodeQL, Bandit and Snyk in CI.

  • Flask
  • Jinja
  • Redis
  • Docker
  • Snyk
  • Cloudflare
Try API Looter ↗
Tulla Contracting home page hero

Client site

Tulla Contracting

Redesigned and rebuilt, with four forms including a job application that takes resume uploads. Static pages on Cloudflare; a Worker handles every form with Turnstile, Cloudflare Email Sending, and R2 for the uploads.

  • HTML
  • CSS
  • JavaScript
  • Workers
  • Turnstile
  • R2
Visit the site ↗

SOCIAL PROOF

Client work and the results it delivered

Tulla Contracting

Construction / Contracting

Redesigned and rebuilt the company's website, turning their brand and the realities of the contracting trade into a responsive site that makes their services easy to find and contact them about.

  • Web Development
  • Responsive Design
  • User Experience
“Working with Duncan was an absolute game-changer for our company. From the very first consultation, he demonstrated an impressive depth of knowledge, creativity, and professionalism that immediately put us at ease. Duncan took the time to understand our brand, our values, and the unique challenges of the contracting industry, translating all of that into a stunning, user-friendly website that exceeded every expectation.”
Visit Website ↗

Stellar Horizon Venture Corp

Upwork client

Restored outbound email after a DNS conflict between Google Workspace and Squarespace, then set up DMARC so mail stopped bouncing or landing in spam, in time for the client meetings that led to a major contract.

  • DNS Security
  • Email Authentication
  • DMARC Setup
“I can't say enough good things about working with Duncan. I ran into a major DNS issue while connecting my Google Workspace and Squarespace accounts that completely broke my email. I could still receive messages, but I couldn't send anything, which became a huge problem because we had important client meetings coming up and I couldn't even send the calendar invites. Duncan jumped in right away, tracked down every issue with my DNS records, corrected the configuration, and also set up DMARC properly so my emails would stop getting rejected or ending up in spam. He explained what was wrong, fixed everything much faster than I expected, and made sure it was all working before wrapping up. Because he got everything resolved so quickly, I was able to send out the meeting invitations, hold the meetings as planned, and ultimately secure a major contract for my company. His work had a direct impact on our business. If you're dealing with Google Workspace, Squarespace, DNS, email authentication, or anything similar, I would absolutely recommend Duncan. He's knowledgeable, responsive, and gets the job done. We'll definitely be using him again for our future IT needs”
View on Upwork ↗

NexGen Truck & Trailer Parts

Truck & trailer parts wholesale

Built their Wholesale Hub instance, the first one live: customer ordering plus inventory management and day-to-day operations, designed to fit their business and wholesalers in general.

  • Custom Platform
  • Inventory Management
  • B2B Ordering
“Duncan was working on an application for my trucking and trailer wholesale parts company. He went so above and beyond, that I now have access to an entire inventory management system, and BOS (Business Operating System). Every single issue we spoke about, he took the time to come up with a solution that would not only work for my specific business, but for wholesalers in general. I would recommend Computer Anything LLC to ANY business with tech issues, regardless of what they are!”
Visit Website ↗

LET’S BUILD

Need a freelancer who can handle frontend, backend, and DevOps?

Tell me what you’re building and I’ll help you scope, architect, and ship it fast.

duncan@computeranything.dev Book a Call