Series A Fractional CTO: The 90-Day Engagement
Table of Contents
- Why Series A Founders Need Fractional CTO Leadership
- What a 90-Day Fractional CTO Engagement Actually Includes
- The First 30 Days: Discovery, Diagnosis, and Quick Wins
- Days 31–60: Architecture, Hiring, and Vendor Independence
- Days 61–90: Investor Readiness, Scaling Patterns, and Handoff
- Pricing, Commercial Terms, and What to Expect
- How to Measure Success: Metrics That Matter
- Common Pitfalls and How to Avoid Them
- Extending Beyond 90 Days: When to Transition
- Next Steps: Getting Started
Why Series A Founders Need Fractional CTO Leadership
You’ve raised capital. Your product works. Now you need to build it like a real company.
This is the moment most Series A founders hit a wall. The technical decisions you made on a seed budget—the monolith that shipped in weeks, the vendor integrations you bolted together, the security story that was “we’ll sort it later”—suddenly matter. Your investors want to know your tech risk. Your first enterprise customer wants SOC 2. Your hiring manager can’t find senior engineers in your city. Your product is slow. Your AWS bill is $40K a month.
You need a CTO. But you can’t afford one yet. And you’re not sure if you want a full-time hire before you’ve validated product-market fit at scale.
This is where a fractional CTO comes in.
A fractional CTO engagement—particularly a focused 90-day sprint—gives you senior technical leadership without the full-time salary and equity commitment. It’s not consulting. It’s not architecture review. It’s operational leadership: someone who sits in your engineering meetings, makes binding technical decisions, hires your first senior engineers, and gets your product and operations ready for the next round of growth.
According to research on fractional CTO trends in 2026, companies bringing in fractional technical leadership during Series A report 40–60% faster time-to-ship, 30–50% reduction in technical debt, and measurably better investor diligence outcomes. The best part: a 90-day engagement is short enough to prove value before you commit to a longer relationship, and focused enough to move the needle on the three or four things that actually matter.
At PADISO, we’ve run dozens of Series A fractional CTO engagements across Sydney, San Francisco, and New York. We’ve seen what works, what doesn’t, and what founders should expect. This guide is what we’ve learned.
What a 90-Day Fractional CTO Engagement Actually Includes
Before we talk about timeline and pricing, let’s be clear about scope. A fractional CTO engagement is not a menu à la carte. It’s a focused package of leadership, decision-making, and execution.
The Core Deliverables
A 90-day fractional CTO engagement from PADISO typically covers:
Technical Architecture and Risk Review
Day one is diagnosis. We audit your codebase, infrastructure, data pipelines, and vendor stack. We’re looking for technical debt, security gaps, scalability bottlenecks, and vendor lock-in. We produce a written risk register: what could break, what’s slowing you down, and what’s a problem now versus a problem in six months.
This isn’t theoretical. We’re running load tests, reviewing database schemas, auditing IAM policies, and checking your observability. We talk to your engineers. We read your Slack. We understand the actual state of your platform, not the state you wish you were in.
Engineering Hiring and Hiring Process Design
Most Series A founders have never hired engineers before. They don’t know what a senior engineer actually costs, where to find them, how to interview for cultural and technical fit, or how to close them in a competitive market.
We design and lead your hiring process. We write job descriptions that actually attract talent. We source candidates—from our network and from the market. We conduct technical interviews. We close offers. By the end of 90 days, you should have at least one senior engineer hired (or in final stages), and a repeatable hiring playbook for the next two.
Vendor and AI Strategy
Every Series A company is drowning in SaaS. You’ve got 20+ subscriptions, three different analytics tools, two CRMs, and you’re not sure if you actually need any of them. We audit your vendor stack, kill what doesn’t matter, and consolidate where possible. We also map your AI readiness: where agentic AI could save you money or speed you up, what you should build versus buy, and what infrastructure you need to stay vendor-independent.
Platform Engineering and Scalability
Your product works at 1000 users. Will it work at 10,000? We review your architecture for scalability, cost efficiency, and operational maturity. We design (and often help implement) patterns for multi-tenancy if you need it, observability and alerting, database scaling, and cost control. If you’re on AWS, we audit your well-architected framework. If you’re planning a major refactor, we help you scope it.
Investor-Ready Tech Story
Your Series B investors will ask hard questions. What’s your tech stack and why? What’s your security posture? How do you handle data? What’s your AI strategy? What’s your hiring plan? We help you build a narrative that’s honest, specific, and investor-ready. This includes a technical diligence document, a product roadmap that aligns with business goals, and talking points for board meetings.
Security Audit Readiness (SOC 2 / ISO 27001)
If you’re selling to enterprise customers, you need SOC 2 Type II or ISO 27001. These take months to implement. We assess your current state, design your compliance programme, and help you get audit-ready. We typically partner with Vanta to automate evidence collection and reduce the manual work. More on this below.
What’s Out of Scope
A fractional CTO engagement is leadership, not execution. We’re not building your product. We’re not writing code (except where it’s necessary to unblock the team or prove a pattern). We’re not doing DevOps full-time. We’re not managing your support queue.
If you need custom software development or platform engineering—a major rebuild, a new data pipeline, an AI agent—that’s a separate engagement. We offer platform development services in Sydney, San Francisco, New York, and other cities for exactly this reason.
A fractional CTO engagement is about leadership, decisions, hiring, and de-risking. It’s about getting your house in order before the next round.
The First 30 Days: Discovery, Diagnosis, and Quick Wins
The first month is about building trust and moving fast on things that matter.
Week 1: Listening and Diagnosis
We arrive with no assumptions. We spend the first week listening.
- Engineering team interviews: One-on-ones with every engineer. What’s working? What’s broken? What’s slowing you down? What do they wish the CTO would fix?
- Founder alignment: Deep dive with you and your co-founders. What are your growth targets for the next 12 months? What’s your Series B story? What’s keeping you up at night, technically?
- Code and infrastructure audit: We clone your repos, spin up your infrastructure, run your tests, and try to break things. We’re looking for obvious gaps: missing tests, no observability, hardcoded secrets, database scaling issues.
- Vendor and tool audit: What are you paying for? What’s actually being used? What could be consolidated or killed?
- Customer and sales calls: We talk to your best customers and your sales team. What are they asking for? What technical concerns come up in deals?
By the end of week one, we’ve got a diagnostic report: a written risk register, a list of quick wins, and a hypothesis about what matters most.
Week 2–3: Quick Wins and Credibility
We move fast on things that are obviously broken and don’t require consensus.
Examples from real engagements:
- Kill a broken CI/CD pipeline: One company was spending 30 minutes per deploy. We fixed it in three days. The team’s morale went up immediately.
- Consolidate observability: Another company had three separate monitoring tools. We migrated to one, cut costs by 40%, and got better alerts.
- Fix a database scaling issue: A third company was hitting query timeouts at peak load. We indexed, denormalised, and added read replicas. Solved in two weeks.
- Audit and tighten IAM: Every Series A company has overly permissive AWS access. We fixed it, documented it, and trained the team.
These aren’t glamorous. But they build credibility. Your team sees that the fractional CTO actually ships, not just talks. And you’ve got momentum heading into the harder work.
Week 3–4: Hiring Plan and Roadmap
By now, we understand your technical gaps. We draft a hiring plan: who you need, when, and why. We also sketch a 12-month technical roadmap that aligns with your business plan.
This roadmap is not a Gantt chart. It’s a narrative: “Here’s what we’re solving this quarter. Here’s what we’re learning. Here’s how that informs next quarter.” It connects technical work to business outcomes. Investors love this.
We also start sourcing your first senior hire. We’re reaching out to candidates, scheduling coffee chats, and building a pipeline.
End of Month 1: Checkpoint
At day 30, we present:
- Risk register: Technical debt, security gaps, scaling bottlenecks, and vendor lock-in, prioritised by impact.
- Quick wins completed: What we’ve shipped, what it cost, what it saved.
- Hiring plan: Role, seniority, salary range, and sourcing strategy for the next 3–6 months.
- 12-month technical roadmap: Aligned with your business plan and investor expectations.
- Vendor audit and consolidation plan: What to keep, what to kill, what to consolidate.
- Investor-ready tech story: Draft narrative and talking points for your next board meeting.
At this point, you should feel like you’ve got a CTO. You’ve got clarity. You’ve got momentum. And you’ve got 60 days left to build on it.
Days 31–60: Architecture, Hiring, and Vendor Independence
The second month is about solving the structural problems and closing your first senior hire.
Architecture and Scaling Patterns
Now that we understand your product and your growth targets, we design for the next phase of scale.
This might include:
- Multi-tenancy design: If you’re selling to enterprise, you need proper tenant isolation. We design the data model, the query patterns, and the compliance boundaries.
- Data pipeline architecture: If you’re building analytics or AI features, we design the data infrastructure. This includes ETL/ELT patterns, data warehouse schema, and cost control (ClickHouse is cheaper than Redshift; Superset is cheaper than Tableau).
- AI and agentic workflow design: If you’re building AI features, we design the architecture: LLM choice, prompt engineering patterns, vector storage, retrieval-augmented generation (RAG), and cost control. We help you understand the difference between a chatbot and an actual agent.
- Observability and cost control: We design your monitoring, logging, and tracing. We also design cost controls: budget alerts, resource tagging, and cost anomaly detection. By the end of 90 days, you should know exactly where your AWS spend is going and have guardrails in place.
If you need detailed platform engineering support, we can escalate to our platform development team in Sydney or your local city. But the fractional CTO engagement covers the design and decision-making.
Hiring Execution
By day 60, we should have your first senior engineer in final stages (offer stage or just accepted). This is hard. Series A salaries are competitive. You’re competing against well-funded startups and big tech companies. You don’t have a strong employer brand yet.
Here’s how we do it:
- Sourcing: We tap our network. We also use LinkedIn, AngelList, and referrals. We’re looking for engineers who have shipped before, who understand early-stage constraints, and who are excited by your problem.
- Screening: We do a 30-minute technical screen. We’re not looking for LeetCode wizards. We’re looking for people who can ship, who care about code quality, and who can mentor junior engineers.
- Technical interviews: We conduct a take-home assignment or a pairing session. We’re evaluating depth, communication, and problem-solving approach.
- Reference checks: We talk to their previous managers. We ask hard questions about strengths, weaknesses, and fit.
- Offer and close: We help you position the role, negotiate the offer, and close the candidate. We also help with equity packages and vesting schedules (4-year vest with a 1-year cliff is standard).
By day 60, you should have at least one senior engineer hired or in final stages. You should also have a repeatable hiring playbook for the next two hires.
Vendor Independence and AI Strategy
We complete the vendor audit and consolidation. We kill what doesn’t matter. We consolidate where possible. We also map your AI readiness: what you should build, what you should buy, and what infrastructure you need to stay independent.
This includes a written AI strategy document: your AI vision for the next 12 months, the business case for each AI initiative, and the technical roadmap to get there.
Days 61–90: Investor Readiness, Scaling Patterns, and Handoff
The final month is about getting investor-ready and setting up for success beyond 90 days.
Investor-Ready Technical Diligence
Your Series B investors will run technical due diligence. They’ll ask:
- What’s your tech stack and why?
- What’s your security posture? Have you had a security audit?
- How do you handle data? GDPR? Data residency?
- What’s your AI strategy? Are you building or buying?
- What’s your hiring plan? Can you execute?
- What’s your technical debt? What’s your plan to pay it down?
- What’s your vendor lock-in? Can you migrate if needed?
We prepare for all of this. We produce a technical diligence document: a comprehensive overview of your architecture, your security posture, your vendor strategy, and your roadmap. This document is honest. It acknowledges debt. But it shows that you’ve got a plan to address it.
We also help you build a product roadmap that aligns with your business plan. This isn’t a feature list. It’s a narrative: “Here’s what we’re solving this quarter. Here’s why it matters. Here’s how it moves the needle on our key metrics.”
Security Audit and Compliance Readiness
If you’re selling to enterprise, you need SOC 2 Type II or ISO 27001. These take months to implement. We assess your current state and design your compliance programme.
We typically partner with Vanta to automate evidence collection. Vanta connects to your cloud infrastructure, your code repos, and your identity provider. It automatically collects evidence of your security controls and compliance practices. This cuts the manual work by 70% and gets you audit-ready in weeks instead of months.
Our security audit service covers:
- Current state assessment: Where are you today? What controls do you have? What’s missing?
- Compliance programme design: What policies do you need? What processes? What evidence?
- Vanta implementation: We configure Vanta, integrate it with your infrastructure, and train your team.
- Audit readiness: By the end of 90 days, you should be audit-ready. Your auditor should be able to walk in and get through SOC 2 or ISO 27001 in 4–6 weeks.
For financial services companies in Australia, we also cover APRA CPS 234, ASIC RG 271, and AUSTRAC compliance.
Scaling Patterns and Operational Excellence
We document the patterns that got you here. How do you do code review? How do you handle incidents? How do you plan releases? How do you track technical debt? How do you measure engineering productivity?
We also design for the next phase of scale. If you’re hiring your second senior engineer, how do you structure teams? How do you delegate? How do you maintain code quality as you grow?
This might sound like management consulting. It’s not. It’s operational. We’re building playbooks that your team can execute without us.
Handoff and Transition Plan
By day 90, we’ve either:
- Handed off to a full-time CTO: If you’ve hired a CTO or a VP of Engineering, we make sure they’re set up for success. We do a detailed handoff, document everything, and stay available for questions.
- Extended the engagement: If you want to keep working together, we discuss what comes next. This might be a longer fractional arrangement, or it might be shifting to project-based work (platform engineering, AI strategy, security audit).
- Moved to a different service model: If you need ongoing support, we might shift to our AI & Agents Automation service or our platform development team.
The key is that you’re not left hanging. By day 90, your team should be capable of executing the plan without us. But we’re available if you need us.
Pricing, Commercial Terms, and What to Expect
Let’s talk money. This is where most fractional CTO engagements fail: unclear pricing and misaligned expectations.
Pricing Structure
A 90-day fractional CTO engagement from PADISO is typically priced as a fixed-fee package, not hourly. This is intentional. We’re taking on the risk of delivering outcomes, not just hours.
Typical pricing ranges:
- $60K–$80K AUD for a 90-day engagement with a Series A company (pre-revenue or under $500K ARR) with a team of 3–5 engineers.
- $80K–$120K AUD for a Series A company with $500K–$2M ARR and a team of 5–10 engineers.
- $120K–$180K AUD for a Series A company with $2M+ ARR, a team of 10+, or complex technical requirements (fintech, healthcare, AI-heavy).
These are all-inclusive: our time, our network, our tools, our accountability. There are no surprise invoices.
We also offer a lower-friction entry point: our AI Quickstart Audit is a fixed-fee 2-week diagnostic for AU$10K. This tells you where you actually are, what to ship first, what to retire, and what 90 days could unlock. Many founders start here, then move into a full 90-day engagement.
What’s Included
For the fixed fee, you get:
- One senior fractional CTO: Typically 20–30 hours per week, embedded in your team.
- Access to our network: Hiring support, vendor introductions, technical advisors.
- Documented deliverables: Risk register, hiring plan, roadmap, investor-ready tech story, security audit readiness.
- Weekly check-ins: We meet with you every week to review progress and adjust priorities.
- Slack/email support: You can reach us between meetings if something urgent comes up.
- Handoff support: If you hire a full-time CTO, we help with the transition.
What’s Not Included
- Custom development: If you need code written, that’s a separate engagement (our platform development service).
- Ongoing support beyond 90 days: If you want to extend, we discuss pricing for the next phase.
- Equity: We take cash, not equity. We’re not a co-founder. We’re a service provider.
- Exclusivity: We work with other companies. We just don’t work with direct competitors.
Payment Terms
Typically:
- 30% upfront when we sign the engagement letter.
- 40% at day 30 (end of discovery phase).
- 30% at day 90 (delivery of final report and handoff).
We’re flexible on this if you have a different cash flow or investor timing.
Why Fixed Fee?
Fixed fee aligns incentives. We’re not trying to maximize hours. We’re trying to maximize outcomes. We want you to succeed. We want your team to be capable without us. We want you to raise your next round. That’s how we build a reputation.
Hourly billing creates perverse incentives: the consultant wants the problem to be bigger and take longer. Fixed fee is the opposite. We want to move fast and solve the problem.
How to Measure Success: Metrics That Matter
At the end of 90 days, how do you know if the engagement worked?
We measure success against three categories:
Technical Outcomes
- Technical debt quantified and prioritised: You have a written risk register. You know what could break and when.
- Architecture designed for the next phase of scale: You can support 10x growth without a major refactor.
- Observability and cost control in place: You know where your spend is going. You have alerts. You have guardrails.
- Security audit readiness: If you need SOC 2 or ISO 27001, you’re audit-ready (or on track to be within 4–6 weeks).
- Vendor strategy clarified: You’ve killed what doesn’t matter. You’ve consolidated where possible. You understand your lock-in.
Hiring Outcomes
- At least one senior engineer hired or in final stages: You’ve got momentum. You’ve got a repeatable hiring playbook.
- Hiring process designed: You know how to interview, how to source, how to close. Your team can execute without the fractional CTO.
- Salary and equity benchmarked: You know what to pay. You understand the market.
Business Outcomes
- Investor-ready tech story: You can articulate your technology strategy in 5 minutes. You have a diligence document. You have talking points.
- 12-month roadmap aligned with business plan: Your engineering team knows what matters. They know how their work moves the needle.
- Team confidence: Your engineers feel heard. They feel like there’s a plan. They’re more likely to stay.
- Decision-making clarity: You know how to make technical decisions. You’re not blocked on architecture questions.
Some of these are quantifiable. Some are qualitative. But they all matter.
Common Pitfalls and How to Avoid Them
We’ve done this dozens of times. Here are the patterns we’ve seen fail:
Pitfall 1: Unclear Scope or Changing Priorities
The problem: You start with one set of priorities (hiring, architecture, security). Midway through, you decide you actually need a major product refactor. Or you want to build an AI feature. The fractional CTO is now pulled in five directions.
How to avoid it: Write down your three priorities at the start. Communicate them to your team. If something new comes up, we discuss it explicitly. We might say, “Yes, we can do that, but it means we deprioritise hiring.” Clear tradeoffs.
Pitfall 2: Treating the Fractional CTO Like a Consultant
The problem: You ask for a report. You don’t act on it. The fractional CTO has no authority to make decisions. Nothing changes.
How to avoid it: The fractional CTO needs decision-making authority. They need to be able to say, “We’re killing this tool,” and have that stick. They need to be in your engineering standup. They need to be involved in hiring decisions. They’re not advisory. They’re operational.
Pitfall 3: Not Enough Time from the Founder
The problem: The fractional CTO wants to meet weekly. You’re too busy. You cancel meetings. You don’t read the reports. Nothing gets decided.
How to avoid it: Block 2–3 hours per week for the fractional CTO. This is non-negotiable. If you’re too busy to spend 2–3 hours per week on your technical strategy, you’re too busy to run the company.
Pitfall 4: Misaligned Expectations on Hiring
The problem: You expect the fractional CTO to find and close your next three senior engineers. They find candidates. But you don’t like them. Or you don’t move fast enough on offers. The candidates accept other jobs.
How to avoid it: Be clear about what hiring success looks like. We source and interview. You make the final decision and close the offer. We help with messaging and negotiation. But you have to move fast. In a competitive market, the best candidates have multiple offers.
Pitfall 5: Not Documenting Decisions
The problem: The fractional CTO makes a decision. Three months later, a new engineer joins and asks, “Why did we choose this architecture?” No one remembers. The decision gets questioned.
How to avoid it: We document everything. Architecture decisions go in an ADR (Architecture Decision Record). Hiring criteria get written down. Security policies get documented. Your team can execute without the fractional CTO because everything is written down.
Extending Beyond 90 Days: When to Transition
At day 90, you’ve got a choice.
Option 1: Hire a Full-Time CTO
If you’ve found someone great and you’re ready to commit, hire them. We help with the transition. We do a detailed handoff. We’re available for questions for the first month or two. Then you’re off.
This is the ideal outcome. You’ve got a CTO who understands your company, your team, and your roadmap. They can execute independently.
Option 2: Extend the Fractional Engagement
If you’re not ready to hire a full-time CTO—maybe you’re still validating product-market fit, or you’re waiting for the next round of funding—you can extend the fractional engagement.
Typical extensions are 3–6 months at a reduced rate (maybe 20% discount). This gives you continuity while you figure out your next hire.
Option 3: Shift to Project-Based Work
If you’ve got a specific project—a major platform refactor, an AI feature, a security audit—we can shift to project-based engagement. This is where our platform development team comes in.
We design the project, scope the work, and execute. You get a dedicated team for 2–3 months. Then they hand off to your team.
Option 4: Ongoing Advisory
Some companies want ongoing CTO advisory: quarterly board meetings, annual strategy reviews, hiring support as you scale. We offer this too.
You get monthly or quarterly office hours with a senior CTO. You can ask questions, get advice, and get introductions. It’s lighter than a fractional engagement, but it’s there when you need it.
If you’re in Sydney, San Francisco, or New York, we have dedicated teams for CTO advisory. We can also serve companies in other cities.
Next Steps: Getting Started
If you’re a Series A founder and you’re thinking about bringing in fractional CTO leadership, here’s how to move forward:
Step 1: Assess Your Current State
Start with our AI Quickstart Audit. It’s a fixed-fee 2-week diagnostic. We tell you where you actually are, what to ship first, what to retire, and what 90 days could unlock. It’s AU$10K. It’s the fastest way to get clarity.
Step 2: Book a Call
Schedule a 30-minute call with one of our fractional CTOs. We’ll discuss your situation, your priorities, and whether a 90-day engagement makes sense. We’ll also talk about pricing and timing.
You can book a call here:
- If you’re in Sydney: Book a call with our Sydney CTO advisory team
- If you’re in San Francisco: Book a call with our San Francisco CTO advisory team
- If you’re in New York: Book a call with our New York CTO advisory team
- Or visit our services page to learn more about all our offerings.
Step 3: Align on Scope and Priorities
If we decide to work together, we’ll spend a week understanding your situation. We’ll interview your team. We’ll audit your codebase. We’ll talk to your investors (if relevant). Then we’ll propose a scope: three priorities for the 90 days.
These might be:
- Hiring: Find and close your first senior engineer.
- Architecture: Design for 10x scale and document it.
- Investor readiness: Build a diligence document and a roadmap.
Or they might be:
- Security: Get audit-ready for SOC 2.
- Cost control: Cut your AWS bill by 30%.
- AI strategy: Design your AI roadmap for the next 12 months.
It depends on your situation. But we’ll be clear about what we’re committing to.
Step 4: Execute
We start on day one. We’re embedded in your team. We’re in your standups. We’re making decisions. We’re shipping.
Every week, we check in. We review progress. We adjust priorities if needed. We keep you informed.
At day 30, we present our first set of deliverables. At day 90, we deliver the full package: risk register, hiring plan, roadmap, diligence document, security audit readiness, handoff plan.
Step 5: Transition or Extend
At day 90, we discuss what comes next. Do you hire a full-time CTO? Do you extend the fractional engagement? Do you shift to project-based work? We help you make that decision.
Final Thoughts
A 90-day fractional CTO engagement is not a silver bullet. It won’t fix a broken culture. It won’t save a product that doesn’t work. It won’t raise your next round for you.
But if you’ve got a good product, a good team, and you’re ready to scale—and you need senior technical leadership to get there—it works. We’ve seen it work dozens of times. We’ve seen founders go from stressed and uncertain to confident and clear. We’ve seen teams go from scattered to aligned. We’ve seen companies go from Series A to Series B ready.
The 90-day engagement is focused. It’s fast. It’s outcome-driven. And it’s designed to set you up for success beyond the engagement.
If that sounds like what you need, let’s talk. Book a call with one of our CTOs. We’ll figure out if it’s the right fit.
And if you want to learn more about our approach, check out our case studies to see how we’ve helped other companies. You can also read more about how to drive success in the first 90 days with a fractional CTO, or explore the fractional CTO playbook to understand the broader context.
For those interested in understanding different service models, we recommend reviewing advisory versus consultative approaches to see how fractional CTO engagements differ from traditional consulting.
If you’re curious about when to hire a fractional CTO, that’s another useful reference. And for a deeper dive into fractional CTO priorities, this talk covers communication, delegation, and scope adaptation over short engagement horizons.
For those building roadmaps, Atlassian’s guidance on roadmap planning is invaluable for aligning a 90-day CTO engagement with strategy and delivery.
Finally, if you want to understand the broader trends in fractional CTO adoption, the data-driven article on fractional CTO trends in 2026 provides context on engagement structure, decision rights, communication cadence, and exit planning.
Let’s build something great together.