Clear thinking for
better products.
Casta Product provides hands-on fractional product leadership for AI, fintech, and digital teams. Led by Karina Mashkantseva, I work directly with founders and engineering to clarify priorities, strengthen requirements, and move from product uncertainty to shipped progress.
Is your product work stuck in ambiguity?
You have a product to build, but the next decision is unclear. I help you decide what matters, structure the work, and move the team forward.
For founders and small teams that need to clarify an MVP, prioritise the roadmap, or establish a practical product operating rhythm.
For product and engineering teams that need temporary product ownership, clearer requirements, better delivery coordination, or support on a complex initiative.
Too many ideas, no clear priority.
Customer requests, investor feedback, and internal brainstorms compete for developer attention. Sprints drift without an explicit decision on what not to build right now.
Engineering is building, but requirements keep changing.
Developers hit hidden edge cases halfway through implementation. Rework multiplies, estimates slip, and engineers become frustrated translating vague briefs into production code.
Your MVP is expanding before the core journey works.
Features keep getting added before the primary user loop is proven with real data. You spend months building peripheral functionality while the core monetization journey stays unverified.
You need product ownership before hiring full-time.
Hiring a full-time Head of Product takes months and significant equity. You need immediate, disciplined product ownership to ship this quarter's milestones.
- A software development agency. I provide hands-on product leadership, discovery, and requirements ownership—not an outsourced dev shop.
- Someone to replace your entire engineering team. I partner with your existing engineers and designers to make their work clear and actionable.
- A strategy deck without delivery involvement. I stay close to the work, the backlog, and the sprint execution.
- Guaranteed growth without access to users, data, or the team. Real product progress requires direct access to reality, metrics, and team collaboration.
Ways to work together.
Practical product leadership with tailored scoping and clear outcomes. Every format is designed to unblock engineering and give you immediate momentum.
Resolve one important product question.
For one defined product choice, scope conflict, prioritisation issue, or backlog bottleneck.
- Review of one defined product question or proposal.
- Structured decision session.
- Options and trade-offs.
- Written recommendation.
- Prioritised next steps.
Define what to build before committing development effort.
For teams defining an MVP, new feature, or product area before committing engineering effort.
- Problem and target-user definition.
- Core user journey.
- Prioritised MVP or delivery scope.
- Product brief or focused PRD.
- Up to 3–5 prioritised epics or feature areas.
- Detailed user stories and acceptance criteria for the highest-priority 1–2 areas.
- High-level backlog for deferred items.
- Basic wireframes or information architecture for the core journey.
- Risks, assumptions, and open questions.
- Technical-feasibility alignment.
One product area, feature, or MVP; one primary user segment; one core journey; up to 3–5 prioritised epics/features; detailed requirements for the highest-priority 1–2 areas.
Exact scope is confirmed during kickoff based on feature complexity, dependencies, and team capacity.
Make known product work buildable and testable.
For an active delivery team that needs structured backlogs, sprint readiness, and buildable specifications.
- Backlog clean-up for one product area.
- Prioritisation and sequencing for the next 2–4 sprints.
- High-level delivery outlook for the following 1–2 planning cycles.
- Detailed PRDs or feature specifications for up to 2–3 active epics/features, depending on complexity.
- User stories and acceptance criteria for the agreed near-term work.
- Business-rule and edge-case mapping.
- Definition of Ready and Definition of Done.
- QA verification and release-readiness approach.
- Sprint-planning and refinement rhythm.
- Delivery review template and working agreement.
One product area and delivery team; detailed preparation for the next 2–4 sprints; up to 2–3 active epics/features; high-level sequencing beyond that horizon.
Exact scope is confirmed during kickoff based on feature complexity, dependencies, and team capacity.
Fractional Product Management
For early-stage to growth teams needing dedicated hands-on product leadership.
- Dedicated product ownership embedded directly in your Slack & Linear.
- Running sprint planning, refinement, and delivery reviews.
- Direct liaison between founders, engineering, and stakeholders.
- Structured roadmap prioritization and regular release tracking.
Dedicated embed covering one core product area or delivery team at 1–2 agreed days per week.
Scope and working cadence confirmed mutually during onboarding based on team size and sprint rhythm.
Founder MVP Launch
A focused build-and-handover engagement for founders who need a working web MVP and want to learn how to continue independently.
MVP Blueprint
- Product problem and target user definition
- Core use case & MVP scope definition
- Core user journey & basic information architecture
- Screen and workflow plan
- Tool & implementation approach (no-code, low-code, or AI-assisted)
- Delivery estimate & risks identification
- Explicit list of out-of-scope items
MVP Build & Handover
- Working, responsive web MVP
- Core user journey with essential forms & workflows
- Agreed third-party integrations & data flow
- Basic analytics and SEO setup
- Rigorous functional testing & launch support
- Comprehensive handover documentation & guides
- Two 1-on-1 founder training sessions
- Recorded video walkthroughs & 30-day next-step roadmap
This service is for focused web MVPs and early validation products. It does not include complex custom software, mobile applications, large-scale engineering, advanced security implementation, or compliance certification. For complex technical requirements, Casta Product may work alongside specialist engineers.
Not sure which one you need?
Choose Product Decision Review for one specific question or choice. Choose Product Clarity Sprint to define an entire product, feature, or MVP before building. Choose Product Delivery Setup to structure an active product area and make known work buildable and testable.
For one defined product choice, scope conflict, prioritisation issue, or backlog bottleneck.
Define what to build before committing engineering. Clear user journeys, scope trade-offs, and buildable backlog.
Make known product work buildable and testable. Backlog clean-up, sprint rhythm, and QA readiness for an active team.
Predictable Boundaries, Zero Surprise
Each engagement covers one agreed product area, user segment, and decision scope. The final number of features, stories, and documents depends on complexity and is confirmed in the statement of work.
Transparent Scope Governance
Agreed scope work covers the specific product area, planning horizon, and deliverables listed in the statement of work. Additional features, user segments, integrations, research rounds, or major scope changes are quoted separately.
How I move from uncertainty to shipped progress.
A practical four-stage rhythm that replaces guesswork with clear requirements and disciplined delivery.
Understand
I evaluate the problem space, commercial context, technical constraints, and real user friction before writing a single spec.
Focus
I help make the hard trade-offs, cutting through distractions to isolate the critical user journey that creates measurable business value.
Structure
I translate priorities into clear specifications, edge-case maps, and acceptance criteria that engineering teams can build without hesitation.
Learn
I verify shipped releases against real usage feedback, review delivery metrics, and feed objective insights directly into the next sprint iteration.
Clear ownership. Proven in production.
Direct founder-to-founder partnership combining 0-to-1 startup momentum with enterprise platform rigor.
Karina Mashkantseva
- Fractional Product Manager & 0-to-1 Founder (StensWay)
- Former Platform Product Owner, FNZ WealthTech
- Certified Scrum Product Owner (CSPO)
- ISTQB Certified Quality Engineering Rigor
- Based in Thessaloniki, Greece (CET / EET / GMT)
Work directly with me—from initial brief to shipped release.
When you engage Casta Product, you work directly with me, Karina Mashkantseva. As a hands-on fractional product manager and product owner, you won't be passed off to junior associates, outsourced analysts, or agency account handlers.
I integrate straight into your existing communication cadence—joining your Slack, collaborating in Linear or Jira, and writing tickets your developers can pick up without ambiguity. Having built an AI-enabled coaching platform from zero as a founder and managed platform tools in enterprise wealthtech at FNZ, I understand both the urgency of startup delivery and the rigor required for enterprise scale.
"Good product management isn't about producing endless documentation. It's about giving engineering the clarity they need to ship the right thing the first time."
Enterprise Wealth Calculation Tools
Product Owner for Goal Planner, Portfolio Optimiser, and Cashflow Planner within the enterprise platform. Owned backlogs, business rules, acceptance criteria, calculations, and platform API integrations.
AI-Enabled Coaching Platform
Took an AI-assisted coaching platform from initial concept to live operational release. Designed multi-tenant journeys, prioritized MVP scope, created automation workflows, and led end-to-end testing.
Select a Time for Your Strategy Call.
Directly synced to Google Meet. Pick a convenient 30-minute slot below to review your product challenge, assess engineering readiness, and explore collaboration.
Everything you need to know.
Direct answers on engagement structure, communication tools, and time commitments.
What is Casta Product and how does the fractional model work?
Casta Product (casta-product.com) is the hands-on fractional product management and product ownership practice led by Karina Mashkantseva. We partner directly with early-stage to growth startups, AI companies, and fintech teams that need senior product leadership without the overhead or delay of recruiting a full-time executive.
Depending on your product stage, you can engage Casta Product through a focused 90-Minute Decision Review, a 2-Week Product Clarity Sprint, a 4-Week Delivery Setup, an ongoing Fractional PM embed, or a Founder MVP Launch. We integrate straight into your Slack, Linear, or Jira to structure clear requirements and keep engineering shipping.
How does fractional product management differ from a full-time Product Manager?
A full-time Product Manager provides ongoing ownership as part of your internal team. A fractional engagement gives you focused, hands-on product support for an agreed scope and time commitment—typically around one day per week to start.
I can help clarify priorities, structure the backlog, write delivery-ready requirements, align with engineering and QA, and support the team through delivery while you assess your ongoing product needs.
Which communication and management tools do you work with?
What stage of company is the best fit for Casta Product?
What are your working hours and time zone availability?
How do we handle IP and confidentiality?
All proprietary code, roadmaps, customer data, and requirements written during the engagement remain 100% your intellectual property. A mutual non-disclosure agreement (NDA) is executed prior to sharing proprietary materials.
Can you build my entire product?
Clear terms. Fair practices. Zero surprises.
Operating standards, payment structures, cancellation policies, and pre-purchase legal safeguards before you engage.
Engagement, Refund and Cancellation Summary
Operated by Stensmann Group s.r.o. (Czech Republic, IČO: 11916109). Not registered for VAT; no Czech VAT is added to stated prices.
Decision Reviews & Sprints payable in full prior to kickoff. Founder MVP Launch split 50% before kickoff and 50% before final handover. Retainers monthly in advance.
Product Decision Reviews require 48h notice to reschedule. Fixed-fee engagements may be cancelled before start date for full refund; non-refundable once active work begins.
Statutory 14-day right of withdrawal for consumer buyers. Waived upon express immediate-start consent once fully performed. ADR via Czech Trade Inspection (ČOI).