Fixed fee per phase · 6–12 weeks to a live release · fixed scope
A platform built from scratch, with the money part done right the first time.
For founders and companies without an engineering team. I design and build the product — marketplace, SaaS, wallet, internal accounting tool — in fixed-scope phases, with billing, payouts and ledgers engineered from day one instead of retrofitted in year two. One senior engineer who has done this before, and a codebase you own.
GigSocial's creator marketplace, built from an empty repository and still running with me years later · Sponsored's Stripe Connect marketplace · eifas's fintech platform modernized at 100% uptime · my own products live on Stripe: Count21, eSalon, ArenaMaster.
01 / Fit
Is this you?
The founders this works for have the business worked out and want the software built by someone they can trust with the decisions.
You know the business — the customers, the pricing, how money should move — and you don't have a technical co-founder.
The product takes money: subscriptions, marketplace fees, wallets, payouts, invoices. Getting that wrong isn't a bug, it's a liability.
You've had an agency quote that reads like a menu, or a no-code build that hit its ceiling.
You'd rather one senior engineer make the architectural calls and explain them than manage a team of five.
You have budget for a real build and want a fixed fee per phase, not an hourly meter.
You want to own the codebase, the accounts and the infrastructure from the first commit.
Not sure whether you need a platform, or a Shopify store and a Stripe link? Ask. I'll tell you — including when the answer is “you don't need me yet.”
Who this works for. Founders who have the business worked out and don't want to project-manage getting it built. You get one senior engineer who makes the calls, tells you when something is a bad idea, and ships — you approve phases, not tickets. You don't need to speak the language — I'll explain every decision in plain terms and put it in writing.
02 / Deliverable
What you receive
A live product, in phases you approve one at a time. Each phase ends with something running that you can put in front of customers.
Phase 0 — Scope and architecture: a written plan with what's in phase 1, what it costs, and what's deliberately later. Yours to keep whether or not we continue.
Phase 1 — The core loop, live: the smallest version customers can pay for, with authentication, roles, admin, and the money layer built properly — Stripe Billing for subscriptions, or the marketplace money build for two-sided flows.
Phase 2 onward — Growth: onboarding, search, messaging, notifications, integrations, reporting — in the order the business needs them, each phase fixed-scope and fixed-fee.
Production infrastructure you own: hosting, monitoring, backups, error tracking, deploy pipeline — on accounts in your name.
Plain-language documentation of what was built and why, plus the technical docs a future hire needs.
Handover: you own everything. Keep me on as a fractional lead, hire in-house, or both — the code doesn't care.
03 / Sequence
How it works
- 1
The conversation
You describe the business. I ask the questions that decide the architecture: how money moves, who pays whom, what has to be true on day one. If I'm not the right fit, I say so and, where I can, point you at who is.
- 2
Phase 0 — Scope (1–2 weeks)
Written architecture and a phased plan with a fixed fee per phase. You can take this document to anyone; it's yours whether or not we continue.
- 3
Phase 1 — Build to live (typically 6–10 weeks)
Weekly demos of working software. The money layer — billing, ledger, payouts — goes in first, not last, because it's the part that decides the rest of the architecture.
- 4
Launch, then phase 2
Real customers, real payments, monitoring you can read. Then the next phase, scoped and priced the same way — or a pause, with working software and the docs to hire against.
04 / Access
What I need from you
- A decision-maker who can answer questions within a day or two.
- The business model written down, even roughly: who pays, how much, when, and who gets paid out.
- Budget for phase 0 and phase 1 before phase 0 starts.
- Accounts opened in your name as we go — Stripe, hosting, domain. I set them up; you own them.
You don't need to read code. You need to know your business and make decisions when asked.
05 / Scope
Where the fences are
- For non-technical founders and companies building a product that handles money, with budget for a serious build.
- Not for idea validation on a shoestring or a pitch-deck prototype. At that stage a no-code tool and a Stripe Payment Link will serve you better and cost less — and I'll say so.
- Not for rescuing someone else's half-finished build. That starts with an independent review, not a rebuild.
- Visual design and mobile apps come from a vetted network I've worked with for years; one point of accountability stays with me.
- Each phase is fixed-scope. Changes mid-phase go into the next phase, not into the current invoice.
06 / Confidentiality
Confidentiality
A mutual NDA is available on request before we start — I'll sign yours or send mine. The code is written in your repository, under your ownership, from the first commit. There is nothing to hand back later.
I keep a private reference architecture that makes every build faster. Nothing specific to your business goes into it.
AI-assisted development tooling is used under the same confidentiality obligations, behind the same review gates I run on my own production systems. You can opt out before we start.
07 / FAQ
Straight answers
How much does a platform build cost?
It depends on scope, which is exactly why phase 0 exists. For orientation: the money layer alone — ledger, payouts, escrow — is a €12–25k fixed-fee build, and a first live release of a complete platform is typically a multiple of that. You get an exact number per phase before each phase starts, never an hourly estimate.
Why phases instead of one quote?
Because a single quote for a whole product is either padded or wrong. Phases keep each fee honest, and you can stop after any of them with working software and documentation.
Who owns the code?
You do, from the first commit, in a GitHub organization in your name. Same for Stripe, hosting and every other account.
What stack will you use?
Rails or Next.js on Postgres, Stripe for money, boring infrastructure you can hire for. The choice is made in phase 0 and written down with the reasons, so a future engineer understands it.
How does one engineer ship a whole platform?
I run an agent-assisted delivery setup for the mechanical work, behind the same review and test gates I use on my own production systems. That's why a solo engagement ships at team pace. The judgment — architecture, money flows, what not to build — is mine.
What happens when it's live?
Three options: I stay on as fractional lead at €8–15k a month, you hire in-house against the documentation, or both. The handover is designed for all three.
Who does the work?
Andrej Dragojevic, directly. Not an agency, not a junior with a checklist. One senior engineer, a vetted network for design and mobile when scope needs it, EU/US overlap.
One ladder
Audit, migrate, build, or lead — pick the rung that fits
Every engagement is fixed scope with a number attached. The audit is the small first yes; its fee comes off whatever you book next.
Build
6–12 weeks to live
Platform build
Fixed fee per phase
A whole product for founders without an engineering team — with billing, payouts and ledgers engineered from day one.
You're here
Tell me what you're building. The first conversation is how the scope gets written.
Fixed-scope phases, one senior engineer, a codebase you own. No booking link — write to me, I reply within one business day.
No booking link, on purpose. Write to andrej@invocation.io or use the form. I reply within one business day.