Comparison · Engagement model
Monthly retainer or fixed price for AI
Engaging an AI partner with a monthly retainer and dedicated team, or with a fixed-price one-off project. What works for an SME.
In brief
If the scope is clear, stable and limited, a fixed-price project gives budget certainty and is the simplest choice. If the process is complex, evolves as you build it, or you plan to continue over time, a monthly retainer with a dedicated team handles change better and reduces renegotiations. The right question is how stable your scope is, not which model sounds cheaper.
Option A
Monthly retainer with a dedicated team
You pay a monthly fee for dedicated people (Project Manager + AI Engineer) with a combined hours pool, and client-approved milestones drive the work.
Pros
- +Absorbs scope changes without renegotiating the contract every time
- +With Soraia, unused hours roll into later months and excess hours are credited against the following ones
- +Naturally covers evolution and maintenance after the first release
- +A stable team that builds knowledge of your process month after month
Cons
- −Total cost is less predictable up front if you don't set a clear goal
- −Requires an internal point person to set priorities and approve milestones
- −If the pace of work drops, you risk paying for hours you don't fully use
Best for
- SMEs with a complex process, or one that changes as you build it
- Those expecting the agent to evolve over time, not just a single release
- Companies that want a team that stays and knows the context
Option B
Fixed-price AI project (one-off)
You agree scope, deliverables and price in advance, and pay a set amount for that defined perimeter.
Pros
- +Certain, predictable budget: you know exactly what you spend
- +Easy to get approved by a CFO or board because it's a single figure
- +Clear vendor accountability on the agreed perimeter
Cons
- −Every change to scope becomes a renegotiation, often slow
- −Post-release maintenance and evolution are usually excluded
- −If the perimeter is mis-estimated, the vendor cuts quality or you go over budget
- −Poorly suited to processes you only truly understand while building them
Best for
- Clear, stable, bounded scope from the start
- A single well-defined agent or automation
- Those who need a firm number for an already-approved budget
| Criterion | Monthly retainer with a dedicated team | Fixed-price AI project (one-off) |
|---|---|---|
| Budget predictability | Medium (monthly fee, depends on pace) | High (fixed figure) |
| Flexibility on scope changes | High (absorbed in the hours pool) | Low (renegotiation for each change) |
| Evolution and maintenance | Included in the retainer | Usually excluded from the fixed price |
| Fit for changing processes | Yes | No, needs a stable scope |
| Code ownership | Client's from day one | Depends on the contract |
| Typical starting point | From 3,000 euro per month | One-off figure agreed on scope |
The verdict
This isn't an ideological choice, it depends on how stable your scope is. If you know exactly what you want to build and it won't change, fixed price gives budget certainty and is easier to approve. If the process is complex, only becomes clear as you build it, or you plan to evolve and maintain it, a monthly retainer with a dedicated team handles change without constant renegotiations. Soraia works on a retainer precisely because AI agents almost always evolve after the first release, but still sets milestones and an agreed target: so you get the flexibility of a retainer plus a clear obligation of result.
FAQ
What people usually ask us.
With a monthly retainer, do I still pay if I do little work one month?
Isn't fixed price always safer for my budget?
Does a retainer lock me into the vendor?
How do you handle maintenance and evolution after the first release?
How do I choose between the two models for my case?
Not sure which one fits your case?
20 minutes with the CEO to work out the right choice for your processes. No pitch, no obligation.
