Building a SaaS Product With an Agency

What an agency is good for

Getting from nothing to a working product in months rather than the year it takes to hire, onboard and ramp a team. That is a real advantage when the market window matters or the funding is contingent on evidence.

We have built first versions that raised the round that hired the team that took over. That is a good outcome and it is the one to plan for.

What an agency cannot do

• Decide what your product should be — that is the founder's job and cannot be delegated
• Care about it at 11pm the way a founder does
• Talk to your customers with your context
• Own the roadmap past the horizon you are paying for

The products that failed with us were the ones where the client wanted us to decide what to build. The ones that worked had a founder who knew, and used us to move faster.

Structuring the engagement

1. Discovery and prototype, 2–4 weeks. A clickable version to put in front of ten potential customers.
2. Build the first version, 10–16 weeks. One core workflow, done properly.
3. Launch and iterate, 3–6 months. Real users, weekly releases, rapid change.
4. Transition. Either handover to your team, or a reduced retainer alongside them.

Naming the transition point at the start changes what gets built. Code written knowing someone else will inherit it is documented differently, and that difference is worth a great deal at handover.

What the first version must contain

• One workflow, complete — not three, half-built
• Multi-tenancy from day one; retrofitting it is a rewrite
• Sign-up, billing and cancellation, because a product nobody can buy is a demo
• Basic analytics, or you cannot tell what is working
• An admin view so you can support customers without a developer

Multi-tenancy is the one that catches people. It touches every query in the system, and adding it in month eight is genuinely a rebuild.

Owning what you paid for

1. The repository is in your organisation from the first commit
2. Every third-party account is in your name
3. Architecture decisions documented as they are made, not at the end
4. No agency-proprietary framework anywhere in the stack
5. Onboarding documentation written for a developer you have not hired yet

Ask any agency you speak to how a new in-house team would take over. A vague answer is the answer.

The honest cost picture

A first version is typically £40,000–£120,000 depending on the workflow. Then iteration for six to twelve months, then either a team or a retainer.

Where founders get caught out is assuming the build is the cost. Support, hosting, payment fees and the iteration that follows launch are ongoing, and a product that launches with no budget left to respond to its first users tends not to have second ones.

Frequently asked questions