We get asked the build-vs-buy question on almost every first call. The honest answer depends on a handful of numbers that most fintech product leads and CTOs haven't stress-tested. This post is the model we use when we walk through it on calls. You can copy it, tear it apart, and plug in your own numbers.

The scenario: a MiCA-licensed neobank or crypto-native fintech wanting to ship wallets (AA-native), on/off-ramps, stablecoin bill-pay, simple automation (DCA, take-profit), plus the compliance stack (Travel Rule, AML, audit log). 100k end-users at year-end, scaling to 200k in year two. EU-only at first, then MENA.

We model it three ways.

Option A: build in-house

You hire a specialist team. You integrate the sub-vendors yourself. You own the code end-to-end.

Year-one costs

  • Engineering team (loaded cost, EU senior rates):
    • 2 senior backend engineers (Web3 plus fintech): €140k/yr each. €280k.
    • 1 senior frontend engineer: €130k. €130k.
    • 1 DevOps / platform engineer: €130k. €130k.
    • 1 engineering manager (part-time, 50%): €170k × 0.5. €85k.
    • Total eng: €625k.
  • Compliance team:
    • 1 compliance engineer with MiCA plus EU TFR experience: €120k. €120k.
    • 1 compliance lead (part-time, 50%): €150k × 0.5. €75k.
    • External EU fintech counsel retainer plus opinions: €60k.
    • Total compliance: €255k.
  • Vendor integrations (direct contracts, licensed crypto fintech tiers):
    • AA wallet infra (ZeroDev or Biconomy enterprise): €60k/yr.
    • Ramp aggregator (Onramper or Meld): €36k/yr minimum.
    • Travel Rule (Notabene or 21 Analytics): €40k/yr.
    • AML (Chainalysis KYT or TRM): €90k/yr.
    • EMI rails (Modulr/Banking Circle, setup plus minimum): €30k/yr.
    • Custody (Fireblocks or equivalent, if custodial path): €120k/yr (skip if non-custodial).
    • Total vendors: €256k (or €376k with custody).
  • Infrastructure (cloud, observability, security tooling): €60k.
  • Smart-contract audits (tier-1 firm, one round plus remediation): €80k.
  • Security certifications (SOC 2 Type I program start): €40k.
  • Opportunity cost of eng team not working on the partner's core product: we leave this off the cash model but it's where most internal build decisions actually fail. It belongs on your scorecard.

Year-one total (in-house, non-custodial path)

€1.32M cash, plus €625k opportunity cost = effective €1.95M.

Custodial path adds €120k. Range with realistic EU senior rate variance: €1.8M to €2.5M first-year.

Months to first production feature

Team hired: months 1-3. Foundation code (auth, base SDK internals, chain clients, KMS): months 3-5. First end-to-end feature (wallets plus one ramp plus Travel Rule plus first AML hook): months 5-8. Compliance pre-audit and production readiness: months 9-12. First real user in production: typically month 10-14.

Option B: five specialist vendors, no bundled orchestration

You skip the full in-house build. You integrate the specialist vendors yourself but don't build custom wallet or ramp code. This is the most common "we'll just glue it together" pattern.

Year-one costs

  • Engineering team (smaller, because vendors do the heavy lifting):
    • 1 senior backend engineer (integration lead): €140k.
    • 1 mid backend engineer: €95k.
    • 1 frontend engineer: €100k.
    • Partial DevOps + EM: €60k.
    • Total eng: €395k.
  • Compliance:
    • 1 compliance engineer: €120k.
    • Counsel retainer: €40k (lighter because fewer original opinions needed).
    • Total compliance: €160k.
  • Vendor contracts (same list as Option A): €256k.
  • Integration overhead (sub-processor paperwork, DPAs, joint security reviews across 4-5 vendors, annual re-certifications): €40k (soft cost but real).
  • Infrastructure + observability: €45k.
  • Smart-contract audits (for your own wallet contracts, if you deploy any): typically skipped at this tier. €0.

Year-one total

€896k cash, plus €395k opportunity cost = effective €1.29M.

Range with realistic EU senior rate variance and vendor tier choices: €420k to €780k cash (using lower-end vendor tiers) through €1.0M to €1.3M (with enterprise vendor tiers and heavier integration team).

Months to first production feature

Integration work is shorter than full build but the compound is real. Each vendor has its own DPA, sub-processor list, sandbox quirks, webhook format, and paperwork cycle. Partners on this path typically ship 6-9 months after kickoff.

Option C: one bundled infrastructure vendor

You integrate OVAAL. One contract, one SDK, one compliance pack covering every sub-processor downstream.

Year-one costs at the Scale tier (80k users, typical for this scenario)

  • OVAAL setup: €32,500 one-time.
  • OVAAL SaaS (Scale tier): €4,999/mo × 12 = €59,988.
  • OVAAL transaction share (18% of OVAAL's take, estimated): €45,600/yr.
  • Your integration team (OVAAL integration is 4 to 8 weeks of focused work):
    • 1 senior backend engineer, 2 months: €140k × (2/12) = €23,333.
    • 1 frontend engineer, 2 months: €100k × (2/12) = €16,667.
    • Total integration eng: €40k.
  • Your compliance review (reviewing OVAAL's compliance pack, signing DPA): €15k (2 weeks of compliance lead time).
  • Counsel (reviewing OVAAL's DPA, not drafting fresh opinions): €10k.
  • Infrastructure + observability (smaller footprint): €20k.

Year-one total

€223k cash including the integration engineering burst. After integration, monthly run-rate is €4,999 SaaS plus transaction-share only. No ongoing full-time eng team dedicated to crypto infrastructure.

Range across tiers (Launch at 25k users → Enterprise at 200k+ users with full dual-regime): €180k to €280k first-year cash.

Months to first production feature

4 to 8 weeks from signed paperwork to cohort production. First 50-500 real users in month 2 or 3 post-signing. Full GA in month 3-4.

Side-by-side

                        In-house     Specialists    OVAAL
                        (Option A)   (Option B)     (Option C)

Year-1 cash             €1.32M       €896k          €223k
+ opportunity cost      €625k        €395k          €40k
= effective cost        €1.95M       €1.29M         €263k

Months to first prod    10-14        6-9            2-3
Vendor contracts        4-6          4-5            1
Compliance packs        1 (yours)    1 (yours)      1 (ours to yours)
API surfaces to learn   5+           5+             1
Ongoing FT team needed  4-6          2-3            0.25 (support only)

Where the math changes

Option A wins if:

  • You need capabilities outside any vendor's scope (licensed custody, non-EU jurisdictions, exotic chains, bespoke compliance logic regulators require for your license).
  • Your crypto stack is your core differentiator and you need to own every line of it.
  • You already have the senior Web3 team on payroll and incremental capacity is cheap.

Option B wins if:

  • You need best-in-class depth in one or two capabilities (ZeroDev's AA maturity, Onramper's ramp coverage, Notabene's Travel Rule history) more than you need integration reduction.
  • You're already using one or two of these vendors and the marginal integration cost is small.
  • You have strong engineering capacity to absorb the multi-vendor maintenance load on an ongoing basis.

Option C (us) wins if:

  • Time to market matters more than maximal depth in any single capability.
  • Your product differentiation is in identity, brand, or market fit, not in reimplementing stablecoin orchestration.
  • You want one compliance pack to clear, one vendor relationship to maintain, and published commercial ranges you can budget against.
  • Non-custodial architecture fits your regulatory model (CASP, EMI, VARA, CBB).

Assumptions you should stress-test

  • EU senior eng loaded cost: we used €140k for senior backend Web3. Real numbers vary €110k-€180k across London, Berlin, Amsterdam, Warsaw, Vilnius. Plug your real number.
  • Vendor tier pricing: we used licensed-fintech tier numbers. Startup tiers are cheaper; enterprise tiers at 500k-plus users are materially higher for Chainalysis/TRM and AA infra.
  • Opportunity cost: we added full eng-team cost as opportunity. Some teams treat this as zero (excess capacity), others treat it as 2-3× the salary (real roadmap loss). Your call.
  • Regulatory scope: Option A and B numbers assume EU-only. Adding MENA means regional counsel (+€30-60k), regional compliance tooling, and additional rail relationships.
  • Year two onwards: Option A and B retain the team cost. Option C's marginal cost drops sharply after integration. The crossover advantage compounds.

The real question

The real question isn't "which option is cheapest." It's "where do you want your engineering team's attention?" If the answer is "on our core product differentiation, not on reimplementing orchestration every other vendor already built," Option C pays for itself.

If you want to walk through the numbers with your specific user count, jurisdictional scope, and existing stack, get the integration brief and we'll model it on the first call.

See also: our published commercial ranges and the architecture walkthrough that explains why the integration timeline is what it is.