buildAgency · Custom AI Software

Senior engineer. Production AI apps shipped in 4-8 weeks, from $25K.

I build production AI software for founders and operators in Australia. Most of my time goes into teaching at buildAcademy and shipping at Shopfront. I take on a small number of build projects each quarter when the project and the client are a fit.

If that's you, here's how it works.

Send a Project BriefOr email me directly

Two ways to work with me

Start with Discovery if you're scoping. Skip to Build if you're already there.

Discovery Sprint

1 week
$2,500

A written technical scope you own, whether you build with me or not.

A 1-week engagement to take a rough idea and turn it into a buildable technical scope. You walk away with a document you own: architecture, build estimate, recommended stack, key risks. Use it to build with me, hire another engineer, or build it yourself.

Useful if

  • You have an idea but aren't sure if it's buildable
  • You've got a half-built prototype and want a senior look
  • You want to scope properly before committing real money
  • You've talked to other agencies and the quotes feel off

What you get

  • 1-hour kickoff call to understand the problem
  • Written technical scope (10-20 pages)
  • Architecture diagram
  • Honest build estimate with timeline
  • 30-min review call to walk you through it

Discovery cost is credited toward Build if you continue within 60 days.

Enquire about Discovery

Build

4-8 weeks
From $25,000

Production AI software, deployed and live.

A full custom build, scoped tightly, shipped fast. You get a working application on your own domain: auth, payments, database, AI integration, everything wired up properly. Final scope and exact price are set in Discovery so there are no surprises.

Useful if

  • You're a founder with budget and an idea ready to ship
  • You're a business with a process that needs custom software
  • You've done Discovery (with me or elsewhere)
  • You want one engineer accountable end-to-end, not an agency

What's included

  • Authentication and user registration
  • Stripe integration (subscriptions or one-time payments)
  • Database and data layer
  • AI feature integration (LLM-powered, done properly, not a wrapper)
  • Deployment to your own domain
  • Weekly progress updates
  • 30 days of post-launch support

Final scope and exact price set during Discovery. I take on 1-2 Build projects per quarter.

Enquire about Build

This isn't for you if

Your budget for the build is under $25,000. I run buildAcademy for that audience. You can build it yourself after our 3-week cohort for under $1,000 worth of tools if you like.

You want hourly billing or constant scope changes. I work on fixed scope and fixed price. Changes after Discovery are change orders.

You need an ongoing engineering team or daily availability. I do one-shot builds. If you need a full-time team, I can refer you to people who do that well.

You're optimising for the cheapest option. I'm not the cheapest. Overseas agencies will quote a third of what I will. Some of them are good. Talk to them too.

Still here? Good. Here's a bit about me.

About me

I'm Callum Holt. I'm a senior engineer at Shopfront, an AI-powered resale platform processing thousands of listings per day across eBay, Depop, Grailed, and Shopify. I built and own the AI enrichment pipeline that powers it. Before that I built LinkedIn automation infrastructure at BellaSales, an AI sales platform, on Temporal, Neon, and AWS ECS.

I run buildAcademy, a cohort program teaching non-technical founders how to ship real AI apps. I'm Head of Partnerships at MLAI Australia, and I run buildClub Melbourne, a weekly co-working session for AI builders.

I take on a small number of buildAgency projects each quarter when the work is interesting and the client is serious. That's what this page is for.

Connect on LinkedInEmail me directly

Common questions

Ready to scope your project?

Send a project brief. It takes about 5 minutes. I review every brief personally and reply within one business day, either with a Discovery Sprint proposal, a recommendation to do something else, or an honest "this isn't a fit." No hard sell.

Send a Project Brief

Prefer email? callum@13labs.au