TL;DR — The dominant software-agency model sells you a senior architect on the sales call and assigns juniors to the actual code once the contract is signed. T-Square runs the opposite way: every commit is written and reviewed by engineers with 8+ years of production experience. Here is why we made that choice, what it costs and how to verify it before signing.
The bait-and-switch most clients never see
Walk into a sales call at most large dev agencies and you will meet a principal engineer. They will sketch architectures on a whiteboard, ask the right questions about your domain, and quote a rate that feels reasonable for the seniority on display. Then the contract is signed and the principal engineer disappears.
What ships is a team of 2–4 mid-level or junior engineers, coordinated by a project manager, with the principal engineer doing a one-hour weekly review. You pay a blended senior rate. You get a blended junior team. The principal’s name stays on the contract; the principal’s hands stay off the keyboard.
Why this exists
The model is not malicious — it is economic. Agencies scale revenue by leveraging senior time across more juniors. Margin lives in the spread between senior billing rates and junior salaries. If the agency could replace the seniors entirely with juniors at senior billing rates, they would. Many do.
The cost of this model is invisible until the product hits production: regressions, brittle architecture, technical debt that compounds, security gaps that get caught by auditors instead of code review, and APIs that need to be redesigned 18 months in.
How T-Square works differently
- Every engineer has 8+ years of production experience. No exceptions, no juniors on critical paths, no “we will train them on your project.”
- The person on your sales call writes your code. Not reviews it weekly — actually opens the PRs.
- No offshore sub-contracting. What you sign is what ships.
- One operating tier. No “premium” and “standard” — everyone bills the same because everyone delivers the same.
What it costs (and what it buys)
Senior-only is more expensive per hour. It is usually cheaper per outcome. Senior engineers make fewer architectural mistakes, write less code per feature, ship fewer regressions and reduce the project-management overhead that exists primarily to compensate for junior judgement gaps.
We have run engagements both ways across our 8+ years as a studio. The senior-only model wins on total cost in every project that ran longer than three months. The blended model only wins on short, well-specified work where there is nothing left to think about.
How to verify when hiring a partner
- Ask for the LinkedIn and GitHub of the engineer who will write your code, not the engineer who will pitch it.
- Ask for the names that will appear on the pull requests of your project.
- Ask what the staffing model looks like in week 6, not week 1.
- If the answer is vague, hesitant, or “we will assign someone closer to start,” you are looking at a junior model with a senior-priced wrapper.
Frequently asked questions
How can I verify a vendor is actually using senior engineers?
Ask for the LinkedIn profile and GitHub of the engineer who will write your code, not the sales engineer. Ask for the names on the pull requests of your project. If the answer is vague or “we will assign someone soon,” it is a junior model with a senior-priced wrapper.
Is senior-only more expensive?
Hourly rate is higher; total cost is usually lower. Senior engineers ship fewer regressions, need less project management, write code that is easier to maintain and design architectures that age well. Most studios save the difference within the first quarter.
Working on something similar?
T-Square is an independent software engineering studio. We architect, build and operate production-grade systems for learning, AI and custom software products. Talk to a senior engineer if you’d like a second opinion on your architecture or roadmap.