Every founder who needs software built lands on the same three options: hire an agency, hire through a freelance marketplace, or hire a solo full-stack developer. The advice online is terrible because the person writing it is always selling one of the three. Here's how the math actually works, including the parts that are bad for me to say.
The short answer, in a table
For a first MVP or site rebuild, a single engagement in the €10K–€40K band:
| Solo full-stack dev | Agency | Freelance marketplace | |
|---|---|---|---|
| Typical quote | €12K–€40K fixed | €30K–€120K | €3K–€30K (wide) |
| Time to kickoff | 2–6 weeks | 4–10 weeks | 1–2 weeks |
| Time to launch | 6–14 weeks | 12–24 weeks | 4–20 weeks (unpredictable) |
| Who talks to you | The person writing code | PM, account manager, sometimes the lead | Whoever picked up the brief |
| Scope changes | Fast, usually same day | 1–2 week PM loop | Friction; sometimes invoiced silently |
| Design quality | Depends on the individual | Usually solid, can be generic | Roulette |
| Bus factor | One person | Team, redundancy | Low (you can find another, but continuity is zero) |
| Warranty | Varies; good ones offer 30 days | Usually contractual | Almost never |
| Worst failure mode | Capacity limit, schedule slip | Budget bleed, handoff gaps | Ghosting, broken code |
Those are the tendencies. Individual examples differ. Anyone claiming their model has no downsides is selling.
Where each one actually wins
Solo full-stack developer wins when:
- Scope is one product, one team, 8–16 weeks of work
- You want to talk to the person writing code, not a PM
- You need design, frontend, backend, and deploy all owned by the same person
- Your budget is €12K–€60K and you want to see it go into code, not overhead
- You value speed of decisions over org-chart redundancy
Agency wins when:
- The project is large enough that one person can't physically hold it (6+ months, multiple workstreams)
- You have an existing enterprise procurement process and need MSAs, SOC2, SSO, NDAs vetted by their legal
- You need a specific deep specialty you can't hire directly (real-time ML, embedded, high-frequency systems)
- Your own team is going to be involved heavily and needs a structured counterpart
- You have budget for the PM layer and genuinely benefit from it (multi-stakeholder project, slow-moving org)
Freelance marketplace wins when:
- The scope is tiny and well-defined (€500–€3K, a specific feature or fix)
- You have the technical chops to evaluate code and manage directly
- You're OK rotating contractors and losing context between engagements
- You're buying hours on a specific, tactical thing, not a product
Outside those windows, each model usually burns money.
The red flags, by model
Agency red flags:
- Fixed-price quote with no scope document attached
- Can't tell you which engineer will work on your project
- Sales rep is technical but won't let you talk to the lead engineer
- Case studies listed without metrics (no load times, no conversion numbers, no uptime)
- "Retainer" that starts at €20K/month with no clear deliverable
Freelance marketplace red flags:
- Hourly rate under €40 for a "senior" (either exploitation or misrepresentation, both bad for you)
- Portfolio that's mostly screenshots with no live URLs
- Vague testimonials ("Amazing work!") without project details
- Conversation happens only inside the platform's chat and never on a call
- Unwilling to sign a contract outside the marketplace terms
Solo developer red flags:
- No public case studies with real numbers
- Refuses to commit to fixed scope on work that's clearly scopeable
- Can't walk you through the tradeoffs of their own stack choices
- "I'll do whatever you want" — good contractors push back on specs, they don't agree with everything
- No warranty, no support period, no handoff plan
The honest downsides of the solo model (the one I run)
Fair's fair. I run this model, so I should name what sucks about it:
Capacity. I take two projects at a time. Not twenty. If you find me at the wrong moment, your start date is 6 weeks out. Agencies can usually kick off in a fortnight.
Bus factor. I get sick, I take holidays, I could in theory get hit by a bus. I mitigate this with code in your repo from day 1, staging always live on your domain, docs shipped with every milestone — but redundancy is not the same as having a team of five.
Specialty depth. I'm a strong generalist full-stack. If you need someone who's shipped 50 Redis migrations or 10 Stripe Connect marketplaces, a specialist shop will have more scar tissue than me on that specific thing.
Org match. If you're a 100-person company with procurement, legal review, and a quarterly SDLC, I'm a bad fit. I don't want to be your vendor with 14 approval steps. An agency handles that better because it's their core competency.
If any of those is a hard requirement for you, pick the other option. I'd rather tell you on the call than 3 weeks into a project that doesn't work.
How to actually decide
Four questions, in order:
1. Is the work one coherent product, or is it a portfolio of workstreams? One product → solo wins. Five workstreams running in parallel for 9 months → agency.
2. How much of the budget do you want going into code? Rough rule: solo puts ~85% of the budget into shipped work, agency puts ~55% (the rest is PM, account, design lead, margin). If €30K is tight, solo gives you more product per euro.
3. What's the cost to you if the project takes 50% longer than quoted? If you can absorb a 4-week slip and it's annoying but survivable: solo or agency are both fine. If a slip destroys you (conference demo, funding window, seasonal launch): go with whichever has real scheduling slack. Usually neither — but agencies at least have other engineers they can redirect.
4. Can you write a one-page brief? If yes — solo or an agency that accepts fixed-scope will both give you a comparable quote. If no — you either don't know what you want enough to build it yet, or you need to hire someone to help you figure it out. In that case, start with a short discovery engagement (1–2 weeks fixed price) before committing to a build.
What I'd actually tell a friend
If a founder-friend messaged me and said "I need an MVP, €20K budget, 3 months, I have a clear idea" — I'd tell them to find a good solo developer. I'd warn them about the bus factor, tell them to read case studies with real metrics, and tell them to insist on milestone-based fixed pricing. (More on that in fixed scope vs hourly and MVP costs.)
If they said "€100K budget, 6 months, three integrations with enterprise systems, and legal is going to read the contract" — I'd tell them to pick an agency and be willing to pay for the overhead. They'll need it.
If they said "I need someone to fix a bug in my checkout" — marketplace, pick a €60/hr dev with good reviews, move on.
The models don't compete. They serve different shapes of work. The mistake is picking the wrong one for the shape you have.
If you want a second opinion on whether your project is solo-shaped, agency-shaped, or somewhere in between — I'll tell you honestly on a 20-min call, even if the answer is "not me." Book a call.