We sell all three models, fixed price, time and materials, and a monthly pod, against a public rate grid. The fixed price vs time and materials debate in software development is usually framed as a pricing question. It is a risk-allocation decision: who pays on the day the scope turns out to be wrong.
And the scope turns out to be wrong on most projects. Useful software gets defined while it is being built, even after serious upfront framing. Choosing fixed price vs time and materials for a software development project means deciding in advance who absorbs that uncertainty: you, us, or a mechanism that caps it month by month.
This guide is written from the seller's side, with our incentives on the table. Our public day rates run from 150 to 450 EUR depending on seniority, and our pods from 15 to 40K EUR per month.
Fixed price vs time and materials in software development: the real question
There are three possible answers to the wrong-scope question. On a fixed price, we carry the risk, so we charge for it in the number. On time and materials, you carry it and pay for what is actually consumed. With a pod, the risk is capped month by month: you buy stable capacity and reprioritize inside it.
Across more than 17 shipped projects, the original scope has almost never survived intact. No model removes that uncertainty. Each one decides whose pocket it lands in, and at what price.
Fixed price: what the risk premium buys, and the change-request trap
A fixed price is certainty sold with a premium. When we quote one, we estimate the days, multiply by the grid, then add a margin for what nobody knows yet. Take a scope estimated at 60 days: 20 days of a lead at 400 EUR and 40 days of development at 200 EUR come to 16,000 EUR as a dry sum, and that is never the fixed price. If reality drifts to 80 days, someone pays for those 20 extra days. On a fixed price, that someone is us. We know it at signature, so we price it at signature.
The second mechanism is the change request. A fixed price freezes the scope in writing, and everything outside it becomes a negotiation the seller conducts from a position of strength. An aggressive vendor sells the fixed price low and earns it back on change requests. We prefer to say it before signature: the fuzzier your scope, the higher the premium, or the more change requests will follow. Both at once is the signature of a dishonest quote.
Fixed price remains the right tool when the scope genuinely is stable: a framed migration, a specified integration, a lot with known inputs and outputs.
Time and materials: transparency instead of certainty
On time and materials you buy days at the public rates: 150, 200, 300, 400 or 450 EUR depending on the profile. No risk premium, no change requests, the scope can move every week. A senior at 450 EUR for 20 days costs 9,000 EUR, and you know exactly what those days produced.
The counterpart is demanding. Time and materials moves the risk to your side, so it requires your governance. Someone has to prioritize the backlog, settle trade-offs, read what ships. Without that steering, the model becomes a running meter. The seller's incentive on time and materials is to last. Yours is to steer. The minimum: a weekly review of delivered against planned and a short exit notice.
It fits when the product moves fast and a product owner with real weekly availability exists.
The pod: a stable team sold as a product
The pod answers a problem the other two models handle poorly: building a product over time. You buy a stable team, billed monthly, between 15 and 40K EUR depending on composition.
Concretely, 15K per month maps to one senior at 400 EUR plus two developers at 150 and 200 EUR over a full month. At 40K you are looking at six to seven people covering architecture, development and quality. Steering, quality and contracts stay in Belgium and Switzerland, the engineering runs in our Rabat center. That hybrid model makes these amounts possible at this level of seniority.
The incentive changes shape: a pod renews every month, so it has to prove its value every month. Your budget stays flat, you reprioritize inside known capacity, and the team accumulates knowledge of your business instead of losing it between projects. This is the model behind a booking platform for airport parking we operate, whose scope has kept moving since the first month.
How each model reads in a Belgian public tender
Belgian public buyers think in terms of the tender specifications. Fixed price fits them naturally: comparable prices between bidders, simple award criteria, an obligation of result. Time and materials goes through a framework agreement with day rates per profile. Our public grid maps exactly onto that format, an advantage in evaluation because it can be verified. The pod does not exist as a procurement category: it gets tendered as committed-capacity time and materials, or as a sequence of fixed-price lots. If you buy through public procurement, say so early and we structure the offer accordingly.
The clauses that matter more than the model
A good model under a bad contract does more damage than the reverse. Three clauses weigh more than the choice between fixed price, time and materials and pod:
- Exit: a short notice period and documented reversibility. If leaving is painful, your vendor knows it and negotiates accordingly.
- Intellectual property: the code, the infrastructure and the documentation belong to you on payment, with no carve-out for generic building blocks.
- Key people: the profiles who convinced you in pre-sales must be the ones who deliver, with a say on any replacement.
What each model honestly costs you
A well-priced fixed price costs more than the equivalent time and materials when everything goes well: the premium is lost. Well-steered time and materials consumes internal time that many organizations do not have, and that time never shows up in the comparison. A pod only makes sense over several months: for three weeks of work it is the wrong tool. And no model compensates for an absent sponsor on the client side. We have seen all three fail for that reason, never because of the model itself.
A short decision path
- Stable scope, known inputs and outputs: fixed price, and demand the day-level breakdown and the price of the premium.
- A living product and an available product owner: time and materials on a public grid, weekly governance written into the contract.
- A long build, a flat budget, a team that has to learn your business: a pod between 15 and 40K per month.
If you want to test this reasoning against your own scope, describe it on jadev-corp.com/quote. You get an immediate range on the public grid, then a formal quotation reviewed by an engineer within one business day. The earliest start sits two weeks after your request, the time it takes to compose the right team.