Coherent product build
LifeOS Junior
A coherent, full-stack product build - useful as proof of a complete product shape.
Vue 3 · TypeScript · Express · PostgreSQL · Docker · CI
Serie3 - fractional CTO & senior product engineering
You're not hiring developers. You're installing an engineering organization.
Serie3 is senior engineering leadership in two forms: a fractional CTO for the team you already have, or a fixed-scope build that ships a serious product to production when you don't. Every decision is documented, reviewed, and validated - so what stays behind is a stronger engineering organization than you started with.
Built for funded founders and teams who need senior technical leadership - to strengthen the engineers they have, or to ship the first serious product before they hire any.
01 / What You Get
Not a deliverable. A capability - installed, then yours.
Early technical decisions compound. The traps are familiar: a demo that works but collapses when it has to become a real system, or a growing team with no senior hand on the architecture. Agencies hand back code your team can't extend; freelancers become a single point of failure; hiring a CTO takes six months and a quarter-million a year. Serie3 brings the four things startups usually assemble piece by piece - architecture, senior implementation, predictable delivery, and engineering leadership - and you engage them the way that fits: as a fractional CTO for your team, or as a fixed-scope build. What stays behind, either way, is the system and the standards that outlast the engagement.
01
Architecture that survives contact with reality
A system designed to be built, operated, and evolved - not a prototype you throw away the moment it succeeds.
02
Production implementation, not a proof of concept
The real application, platform, integrations, data model, and deployment surface - shipped, monitored, and handed over with a runbook.
03
Predictable AI delivery
The speed of AI, with every change reviewed against the architecture and every decision recorded - so velocity produces a clean codebase, not one no one can maintain.
04
Technical leverage for the founder
The clarity to raise, hire, and sell - with honest answers about what's solved and what isn't, written where you can use them.
02 / Engagement
Two engagements. Clearly separated.
They don't overlap. One is delivery, the other is judgment. Choose the engagement that matches your current need - they are independent, and can be combined when it creates value.
Option 1 - Build Engagement
You need software delivered.
Whether you're starting from scratch or extending an existing engineering team, Serie3 delivers a defined outcome - architected, shipped to production, and handed over. Fixed scope, fixed fee, a clear end - not an open-ended retainer.
Building a comparable team the usual way means a senior architect and two or three engineers: roughly USD 600k-1M a year, and four to six months to hire. A build engagement compresses that into 8-16 weeks for a single fixed fee.
Three sizes
Focused Build
USD 100k-150k (+0.25-0.5% optional)
6-8 weeks
A narrow product with clear scope, one primary user journey, and limited integration risk.
Core Platform
USD 150k-225k (+0.5-1% optional)
10-12 weeks
A meaningful product surface: backend, frontend, integrations, data workflows, and production deployment.
Complex System
USD 225k-300k (+1-1.5% optional)
14-16 weeks
Platforms involving AI, real-time behavior, multi-role workflows, data infrastructure, regulated domains, or high architecture risk.
Build engagements run USD 100k-300k, optionally paired with 0.25-1.5% equity - upside alignment, never a substitute for the fee.
Option 2 - Fractional CTO
You already have engineers.
I help them become a high-performing engineering organization: setting technical direction, raising the standard, and making delivery predictable. The goal is to leave your engineering organization stronger than when I arrived.
The product is judgment, not code.
Typical responsibilities
- Architecture & technical direction
- Hiring & mentoring engineering leads
- Engineering standards & process
- Safe AI adoption in engineering
- Technical strategy
- Product roadmap
- Executive & board guidance
USD 8-24k / month · ongoing, 1-3 days/week
No software delivery included.
What you keep
Every build leaves behind more than working software: the documented decisions, runbooks, and standards your next team inherits - not a black box they have to reverse-engineer.
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Architecture decisions, written
Each non-trivial choice documented as a decision record. The founder can read it; the next engineer can extend from it.
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Production deployment + runbook
The system ships live, with a runbook covering deploy, rollback, monitoring, and the failure modes that actually matter.
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Weekly founder-readable updates
Plain-English progress every week: what shipped, what's next, what's at risk, what needs your decision.
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An afternoon's handoff
A written handover an incoming CTO or first engineering hire can absorb in an afternoon and pick up from cold.
Starting structures, not menu prices. Final scope is set in a written agreement. Serie3 takes no equity-only work.
03 / The System
AI speed, predictable delivery.
The advantage isn't using AI - everyone uses AI. The advantage is Spec-Driven Engineering: every requirement is written as a spec, every architectural decision is documented, and every change is reviewed and validated against it. The result is predictable delivery - the codebase stays clean and understandable even when it's built at AI speed. It's how one senior architect produces the output of a team without losing control of the result.
- 01
Discovery
Define the business goal, product shape, user journeys, system boundaries, and the technical risks worth taking seriously.
- 02
Architecture
Establish the core model, integration boundaries, deployment approach, data flows, and the non-negotiable quality constraints.
- 03
Governed Build
AI-assisted development under review, with clear ownership, tests, documentation, and decision records at every step.
- 04
Production Readiness
Real users: deployment, observability, a security baseline, and founder-facing technical clarity.
- 05
Handoff
A coherent codebase, architecture notes, operating instructions, and a clear path to hire or continue.
04 / Fit
Built for problems that can't be faked with a template.
Good fit
- You either have an engineering team that needs senior leadership, or you need the first serious product built before you hire one.
- You're funded, revenue-backed, or capitalized enough to invest seriously - from about USD 8k a month, or USD 100k+ for a build.
- The technical work has real weight: architecture, integration, data depth, AI, or operational importance.
- You want senior judgment, not just more hands.
- You value the engineering organization you keep as much as the speed you get.
Not a fit
- You need a landing page or a simple CRUD app.
- You want the cheapest possible MVP.
- You expect equity to replace cash.
- You want a large agency team, or code without architectural judgment.
- You're looking for a permanent co-founder or a full-time CTO seat.
05 / Proof
Why Serie3 exists.
Serie3 was founded by Boban Karisik after two decades designing and leading enterprise software systems. The methodology behind it evolved from solving the same delivery, architecture, and quality problems across real-world platforms, not from theory - the hard part was never writing the software, it was making quality predictable.
The internal lab is proof the method is current: complete, product-shaped systems built with the exact AI-assisted delivery method your engagement would use - same architecture discipline, same documentation, same production hygiene.
01
Government digital services
Identity, integration, auditability, and operational resilience in public-sector systems.
02
Fintech and regulated platforms
Transaction systems, security-sensitive integrations, and availability under real constraints.
03
Operational intelligence
Data platforms, digital twins, simulation, real-time response, and AI-assisted decision surfaces.
04
AI delivery that stays maintainable
A proven way to build with AI agents at speed while keeping the architecture clean, the decisions documented, and the code something a team can still maintain.
Internal Lab
Proof the method is current - not client references.
Enterprise platform credibility
Zora MDM
Enterprise master data management platform with stewardship workflows, auditability, and operational documentation.
PostgreSQL · PostGraphile · Vue 3 · Authentik · NATS
Hard-system credibility
Sentinel
Real-time OSINT and geospatial intelligence system: ingest, normalization, anomaly detection, situation lifecycle, and self-hosted deployment.
Real-time · Geospatial · OSINT · Self-hosted
These are internal lab projects, not client case studies. Their job here is to prove method, range, and engineering seriousness - not to stand in as revenue references.
Evidence
What a build actually produces
No logos. No testimonials. The concrete artifacts a build engagement leaves behind - here is what they are.
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01
Specification
Every feature written as a clear, testable spec before code - so what's being built is agreed up front, not assumed.
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02
Architecture Decisions
A dated record of each significant technical choice and the reasoning behind it - the context your next engineer would otherwise have to reverse-engineer.
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03
Validation Scenarios
The concrete cases the system is checked against - expected behavior, edge cases, and failure modes, written down and run.
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04
Evidence Report
Proof that what was specified actually works: results tied back to each requirement, so 'done' means demonstrated, not claimed.
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05
System Documentation
How the system is built and operated - architecture, data model, integrations, and the runbook to deploy, monitor, and recover it.
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06
Handover Package
Everything an incoming engineer or CTO needs to take ownership in an afternoon - code, decisions, docs, and operating instructions in one place.
24 of these documents from a real build, organized exactly as they're handed over. Your details just let me follow up.
Or read the executive summary (PDF)06 / Contact
Bring a serious problem.
Whether you need a fractional CTO for your team or a serious product built, send a concise note: where you are, what you need, your rough budget and timeline, and why it matters technically. You'll get a real answer within 48 hours.
Not a fit for staff augmentation, generic outsourcing, equity-only projects, a permanent full-time CTO seat, or commodity websites.
FAQ
Questions
Is Serie3 an agency?
No. Serie3 is a senior engineering capability delivered as a system - architecture, predictable delivery, and founder-facing technical judgment. And though it's led by one architect, what you buy isn't headcount: it's the system, standards, and documented decisions a team would produce, without the cost and management of building one.
Do you work for equity only?
No. Every engagement carries a cash fee that stands on its own. Equity is optional upside alignment, never a substitute for budget.
Do you work as a fractional CTO?
Yes - it's one of two separate engagements. As fractional CTO the work is judgment, not delivery: technical direction, hiring and mentoring, engineering standards, and strategy - leaving your team stronger than it started. It's the senior technical seat for the stretch before you hire a permanent one, not a forever executive role. If you need software actually built, that's the separate build engagement - and the two can be combined.
What stage is best?
Seed to Series A. For a build: when you need a serious product before a full team exists. For a fractional CTO: when you have engineers but no senior technical leader to set direction and standards.
What happens when an engagement ends?
After a build: a clean handover to your team, a focused support phase, another defined phase, or help making your first technical hires. After a fractional-CTO engagement: your team keeps the standards and direction, and can roll into a build if delivery becomes the next need.
Are the internal products client case studies?
No. LifeOS Junior, Zora MDM, and Sentinel are internal lab work: evidence of method, architecture range, and delivery discipline - not customer outcomes.