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Every agency offers both and every agency has a preference. This is what each model genuinely protects, what neither of them protects, what has to be true before a fixed price can be quoted honestly, and what to prepare before you ask anyone for a number.
Fixed price moves the risk of an inaccurate estimate to the supplier and requires a scope defined before work starts. Time and material keeps the risk with the buyer and buys the freedom to change direction mid project. For a founder with a fixed budget and a defined first version, fixed price is usually the safer contract. For open ended work, an unclear product or a long running team, time and material is more honest. The deciding question is not which is cheaper but whether the scope can be written down before anyone quotes.
Fixed price buys a defined outcome for a defined amount. Time and material buys people for a period. The first requires the scope up front and prices the uncertainty into the number. The second defers both the scope and the total.
Almost every comparison of the two ends up describing the paperwork. The part that matters commercially is simpler: in one model the supplier absorbs the cost of having estimated badly, in the other you do. That single difference explains every other difference, including why suppliers push whichever one suits the shape of the work in front of them.
It also explains why the models suit different buyers. A company funding a first version from a limited runway needs certainty more than flexibility. A company running a product with a permanent roadmap needs the opposite, because in that setting a fixed scope is a fiction that will be renegotiated every quarter anyway.
Fixed price protects the total. Time and material protects the ability to change your mind. Neither protects the thing most projects actually fail on, which is building a product against a misunderstanding of the business.
The number. You know before you start what the first version costs and what is inside it, which is what makes the decision fundable, defensible to a board and comparable between suppliers. Overruns inside the agreed scope are the supplier's cost, not yours.
Flexibility. Changing direction mid build means a change request, priced separately, because the original number assumed the original scope.
The right to change direction without a negotiation. If your understanding of the product is still moving, or the roadmap is permanent rather than a single release, paying for capacity reflects reality more honestly than pretending the scope is fixed.
Certainty. The total is discovered rather than agreed, and the incentive to estimate accurately sits on the side of the table that is not paying.
Whether the product answers a real problem. Both models will deliver exactly what was agreed, on time, and leave you with an app no one opens. The companies that come to us after a failed project rarely had a contract problem. They had a supplier who understood the framework and not the operation.
A scoping stage before the contract, where the supplier argues with your requirements rather than pricing them.
A fixed price is not a discount. It is a transfer of estimating risk, and it can only be transferred once somebody has read the requirements.
When the scope cannot be written down, when you are buying a permanent team rather than a release, when the work is research, or when the codebase is someone else's and has not been audited yet.
The reverse failure is more common, though. A supplier agrees to a fixed price on a scope no one has read properly, then discovers the gap in month two. At that point the buyer is choosing between a change request and a supplier quietly cutting quality, and neither option was in the plan.
Three things: a scope written at feature level, named constraints, and an agreed definition of done. Without them a fixed price is a guess wearing a contract.
This is why a scoping stage exists. Ours runs as an app discovery workshop, and its output is the document a fixed price is calculated from. The commercial models themselves sit on our pricing page, and the factors that move the number are broken down in our guide to mobile app development cost.
Four things, and none of them is a specification. The business problem, who uses it, the constraints you cannot move, and what the first release has to do. A supplier that needs more than this before talking to you is optimising for paperwork.
Sending the same four things to every supplier also makes the quotes comparable, which is otherwise close to impossible. If you want the longer version, we wrote it up as a guide to briefing an app development company, with the stage by stage view in working with an app development agency.
Fixed price by default, on a scope we wrote together. Changes are priced as changes rather than absorbed silently, and larger contracts carry a one year warranty on what we build.
We prefer fixed price because most of our clients are funding a specific release rather than a permanent team, and because it forces the uncomfortable conversation to happen before the money is spent rather than in month three. The scoping stage is where we argue about what belongs in the first version. The contract is just where that argument gets written down.
Where the work genuinely is open ended, a long roadmap, an internal platform, a product in permanent development, we say so and propose a team instead. Quoting a fixed price on work that cannot be scoped is not a favour to anyone.
The model sits on our fixed price app development page, and the two verticals where it matters most, because the environment is unforgiving and the scope is concrete, are field service app development and custom HVAC software development.
Working from Poland on a nearshore model for clients across Europe and for companies in New York, which in practice means the scoping calls sit inside your working day rather than at the edge of it.
Usually the headline number is higher, because it includes the cost of the supplier carrying the estimating risk. Whether it ends up more expensive depends on how accurate the estimate was, which is exactly the thing neither side knows at signing. What it buys is a total you can plan around.
Under fixed price it becomes a change request with its own scope and price, and you decide whether it is worth it. That sounds rigid, and it is also the mechanism that stops a project drifting. Under time and material the change is simply absorbed, which feels easier and shows up later in the total.
Fixed price, in almost every case, provided the first release can be defined. A defined scope and a known total is what makes the spend survivable if the product needs a second attempt. How we scope that first version is described on our page for MVP development for startups.
Yes, after an audit. The audit answers whether the app can be built and released from a clean machine and what is actually in it, and the first phase is scoped from those findings. The process is described in our guide to taking over an existing mobile app.
Maintenance is a different commitment from a build, because the work arrives rather than being planned. We run it as an agreed monthly scope with a defined response, described on our app maintenance services page and priced in our guide to app maintenance cost.
It depends on whether mobile development is a permanent need or a project. One release every two years does not justify a hired team; a permanent roadmap eventually does. We set the two side by side in building in house versus outsourcing.
Thomas sets the company's long term strategy and direction, identifies market opportunities, and owns business development and client acquisition. He builds strategic partnerships that last beyond a single project. He works with clients from the first strategy conversation, so their business goals, not just their feature list, drive every decision.
Tell us what you are building and what cannot move, and we will tell you whether it should be scoped as a fixed price release or run as a team.
30 minutes, no preparation needed.