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Co-Build vs Agency vs CTO

Year-1 numbers. Speed-to-revenue. Equity math. When each wins.

A
By Antor
· 📅 April 19, 2026 · ⏱ 10 min read

Every pre-seed founder asks the same question in some form: "How do I get this thing built without losing my shirt?" The three real answers — equity-aligned co-build, fixed-price agency, full-time CTO — have wildly different cost, speed, and risk profiles. After running each model across multiple ventures, here's the decision matrix I'd hand to a founder version of myself today.

Define the three paths

Co-Build

An equity-aligned partnership with a founder-operator who brings their team. Cash: low or zero. Equity: 15–35%. Duration: 6–18 months active build + ongoing advisory.

Agency

A fixed-price or retainer engagement with an external team. Cash: high ($8k–$20k/mo). Equity: zero. Duration: project-bounded (4–12 weeks typically).

CTO Hire

A full-time technical co-founder or senior engineering leader. Cash: very high ($180k–$250k/yr). Equity: 1–2%. Duration: long-term (3+ years intended).

Year-1 cost comparison

Assuming you ship a real product (not a prototype) by month 6 and have it live in production by month 12:

Cost typeCo-BuildAgencyCTO Hire
Cash year 1$0–$120k$80k–$200k$220k–$280k
Equity15–35%0%1–2%
Hiring cost00$30k–$50k
Ramp time cost00–$10k$30k–$40k
Team brought along6 people5–8 people0

Speed-to-revenue comparison

How long until you have a paying customer? Real numbers from comparable engagements:

  • Co-build: 8–14 weeks. The partner has shipped 10+ before; pattern recognition collapses decision time.
  • Agency: 12–20 weeks. Good agencies match co-build on raw output but lose 2–4 weeks to scope-mgmt and approvals.
  • CTO hire: 24–40 weeks. First 8 weeks is ramp + first hire (one engineer). Real shipping starts month 3–4.

If runway is < 12 months, this difference matters enormously.

Risk + dilution comparison

Co-build risks

  • Partner doesn't deliver — but 30-day trial sprint mitigates this
  • Higher dilution if Series A pricing is bad (15%+ to partner before Series A)
  • Co-founder dynamics — strategic disagreement at month 18

Agency risks

  • Cash burn with no equity protection
  • Vendor lock-in if they own the codebase weirdly
  • Quality drop after the senior on your pitch is gone

CTO hire risks

  • Bad hire = $80k+ in severance and 4 months of velocity loss
  • Burnout / churn — 30% of pre-seed CTO hires leave within 18 months
  • Decision bottleneck — every architecture decision goes through you both

The decision matrix

Pick your dominant constraint:

Your situationBest fit
Pre-revenue, <$300k runway, no tech co-founderCo-build
Post-revenue, $500k+ runway, fixed scope projectAgency
Post-Series-A, scaling phase, hiring underwayCTO hire
Solo founder, AI-heavy product, no technical backgroundCo-build
Multi-founder team with a domain-expert CTO alreadyAgency (for specialist work)
Regulated industry (banking, healthcare)CTO hire (long-term continuity)

When co-build wins (and when it doesn't)

Wins when:

  • You have a customer wedge but not a product
  • Cash conservation matters more than dilution
  • You want to ship in < 12 weeks
  • You'd benefit from having a peer to make decisions with

Doesn't work when:

  • You're already a strong technical founder — adding another CTO-level peer creates over-redundancy
  • The product is highly regulated or has 3+ year cycle times
  • You're optimizing for max equity retention pre-Series A (then Agency wins)

Real founder examples

Three composite scenarios from real partnerships I've watched (names changed):

Founder A — pre-seed B2B SaaS, 9 months runway, no tech

Picked co-build. Partner brought 6-op team, shipped MVP in 7 weeks, had first paying customer in week 11. Raised $2M seed at month 14. Outcome: founder kept 55% equity, partner has 25%, Series A took 20%. Founder is happy.

Founder B — Series A AI infra play, $4M runway, technical CEO

Picked agency for a 12-week marketing site + analytics dashboard. Spent $80k. Got exactly what they specced. CEO continued running engineering with 4 in-house. Outcome: textbook agency engagement, no surprises.

Founder C — Series B fintech, regulated market, looking for VP Eng

Picked CTO hire. Spent 4 months recruiting, paid $250k year-1 + 1.5% equity. Wrong fit hire month 9, replaced at month 12. Eventually settled with the second hire who's been there 2 years. Outcome: necessary for regulatory + long-term continuity, but expensive year 1.

your move

Founder A's path looks like yours?

Two equity-aligned co-build slots per year. 30-day trial sprint built in. If your situation matches the matrix above, let's talk.

Explore co-build partnership