Fixed-scope contract
A fixed-scope contract is a software agreement that fixes what will be built and the acceptance tests for it before work starts, so both sides agree in advance what counts as finished and what happens if the brief changes partway through.
Submit a project Compare fixed-scope and milestone contractsReviewed by David Nguyen (CEO) · Updated 6 Oct 2026 · 3 min read
This term is one of the entries in the OutsourcingVN glossary of words buyers meet while negotiating a software contract.
Why it matters
The scope is the document a dispute gets measured against. Once requirements and acceptance criteria are written down and both sides sign off on them, a request that falls outside that list becomes a change rather than an argument about whether the original brief covered it. OutsourcingVN is operated by Netbase JSC, and most of the disagreements buyers describe about a past project trace back to a scope that was agreed informally rather than written down this way.
An example in practice
A retailer commissions a checkout rebuild with a written list of payment methods, discount rules and a named acceptance test for each one. Three weeks in, the retailer asks for a loyalty-points redemption flow that was never on the list. Because the original scope is written, that request is recognised immediately as new work needing its own estimate and schedule, rather than something the team should have "just known" to include.
Common misreadings
A fixed scope is not a fixed plan for the whole relationship — it covers one defined piece of work, and a second phase can be scoped separately once the first is accepted. It is also not a promise that nothing can change: a change is still possible, it is simply handled through an agreed change-request step rather than absorbed silently. And a fixed scope does not remove the need for discovery; the scope is only as good as the requirements gathering that produced it, which is why rushing past discovery to "lock" a scope early is a common way these contracts go wrong.
Plan the next step for your project
Common questions
Yes, through an agreed change-request step; the point is that the original list is fixed, not that nothing can ever be added to it.
Usually the supplier drafts it after a discovery phase, and the buyer reviews and signs off on the final version before work starts.
Related decisions
Choosing between a fixed scope, a milestone-based contract and an outcome-based one, and what each shifts between buyer and supplier, is covered in the fixed-scope vs milestone contracts guide. When you know the requirements well enough to write them down, describe them in a brief, and Netbase will respond through Netbase's own outsourcing-services platform; you can submit a project when you are ready.