Building a Secure and Compliant FinTech App: A FinTech CTO’s Guide to Payment Gateways, APIs, and Audits
September 30, 2025Harnessing Data from Unconventional Sources: Can an 1873 Indian Head Cent Inform Algorithmic Trading Strategies?
September 30, 2025As a VC, I’m always hunting for that one detail—the thing most investors miss—that separates a decent startup from a breakout. Lately, I’ve been zeroing in on one factor: **tech stack efficiency**. It’s not flashy, but trust me, it’s the new GTG 1873 Indian Head Cent of startup investing. Let me explain why.
The Hidden Gem in Startup Valuation: Technical Excellence
Think about a rare coin. Its value isn’t just face value—it’s in the mint mark, the luster, the tiny flaws only experts spot. The same goes for startups. The real value isn’t in the pitch deck. It’s in the codebase, the architecture, the way the team builds.
When I review a company, I treat technical due diligence like a coin collector inspecting an 1873 Indian Head Cent. I’m looking for the subtle tells: Is the system built to scale? Can it handle stress? Is it secure? These are the things that determine if a startup is a coin toss or a long-term hold.
Understanding the Tech Stack as a Grading System
Here’s how I break down a tech stack—like a coin grader with a loupe:
- Architecture: Modular? Decoupled? Or is it a tangled mess?
- Performance: Does it buckle at 10,000 users? Or handles 100,000 like it’s nothing?
- Security: Is it a fortress or a leaky boat?
- Maintainability: Can a new hire contribute in a week? Or is it spaghetti code?
- Cost Efficiency: Are they burning $10k/month on AWS for a feature that costs $500?
The ‘TrueView’ of Technical Due Diligence
Surface-level metrics lie. Just like a coin’s TrueView imaging reveals hairlines and contact marks, VCs need to see under the hood. Here’s what I dig into:
1. Code Quality and Modularity
A monolithic codebase is a red flag. Great teams build modular, testable systems. Their code should feel clean—like a well-maintained tool, not a duct-tape repair.
- Modular with clear separation of concerns
- Documentation that’s actually useful (READMEs, API references)
- Consistent coding standards (no “works on my machine” drama)
Here’s what good looks like—a microservice built for flexibility:
// TypeScript + Express.js for clean microservices
class UserService {
private userRepository: UserRepository;
constructor(repository: UserRepository) {
this.userRepository = repository;
}
async createUser(userData: User): Promise
// Validation and logic live here—not buried in a 500-line function
return await this.userRepository.save(userData);
}
}
// Dependency injection keeps it testable and adaptable
const userRepo = new DatabaseUserRepository();
const userService = new UserService(userRepo);
2. Performance Metrics and Scalability
High-performing startups design for scale on day one. I ask: How does it hold up when traffic spikes? Here’s what I look for:
- Load testing (I love seeing Locust or Gatling results)
- Smart database indexing and query optimization
- Async tasks for background work (think: email queues, not blocking HTTP calls)
- CDN and caching—because latency is a silent killer
Example: A startup should show me how their system handles load. Not just “it works,” but “here’s the data.”
// Load test in Python with Locust
from locust import HttpUser, task, between
class WebsiteUser(HttpUser):
wait_time = between(1, 5)
@task
def load_homepage(self):
self.client.get("/")
@task
def load_user_profile(self):
self.client.get("/user/123")
3. Security and Compliance
Security isn’t a checkbox. It’s a mindset. I want to see:
- Regular audits—and not just after a breach
- Strong encryption (AES-256, TLS 1.3, not “we use HTTPS”)
- Compliance with GDPR, SOC 2, HIPAA—whichever applies
- Authentication that’s actually secure (OAuth 2.0, JWT, not “magic links with no expiry”)
Here’s a secure auth flow—short, but it shows they’re thinking ahead:
// JWT with refresh tokens—because 24-hour sessions are a risk
const jwt = require('jsonwebtoken');
const bcrypt = require('bcrypt');
class AuthService {
async login(email: string, password: string): Promise
const user = await this.userRepository.findByEmail(email);
if (!user || !await bcrypt.compare(password, user.passwordHash)) {
throw new Error('Invalid credentials');
}
const accessToken = jwt.sign(
{ userId: user.id },
process.env.JWT_SECRET,
{ expiresIn: '15m' }
);
const refreshToken = jwt.sign(
{ userId: user.id },
process.env.REFRESH_SECRET,
{ expiresIn: '7d' }
);
return { accessToken, refreshToken };
}
}
Seed Funding vs. Series A: The Tech Stack Evolution
Seed Stage: Proving Technical Competence
At seed, I’m not looking for perfection. I’m looking for **technical discipline**. The team should build fast, but not hacky. Show me:
- Clean code that’s easy to understand
- Basic DevOps (CI/CD, automated tests—no “we’ll do it later”)
- Monitoring (Sentry, LogRocket—so they know when things break)
- A roadmap that’s realistic, not just wishful thinking
At this stage, the team should say: “We built this fast, but we didn’t sacrifice quality.”
Series A: Scaling with Efficiency
By Series A, the system should breathe under pressure. I want to see:
- Cloud-native architecture (Kubernetes, serverless—not just “we’re on AWS”)
- Cost optimization (auto-scaling, spot instances—not $100k/month for a beta)
- Observability (distributed tracing, APM—so they see the full picture)
- Leadership (a CTO who’s built systems that scale, not just features)
Example: A startup using AWS Lambda and DynamoDB for a serverless API—low cost, high scale:
// Serverless API with AWS Lambda and DynamoDB
const AWS = require('aws-sdk');
const uuid = require('uuid');
const dynamoDb = new AWS.DynamoDB.DocumentClient();
exports.handler = async (event) => {
const data = JSON.parse(event.body);
const params = {
TableName: process.env.TABLE_NAME,
Item: {
id: uuid.v1(),
data: data,
createdAt: new Date().toISOString()
}
};
await dynamoDb.put(params).promise();
return {
statusCode: 201,
body: JSON.stringify(params.Item)
};
};
What Investors Look for in a Tech Stack: The VC Checklist
Here’s my go-to list when reviewing a startup technically:
1. Technical Debt Assessment
- How much of the codebase is patchwork?
- Is there a plan to fix it? Or just “it works, so we’ll leave it”?
- Are there tests (unit, integration, E2E)—or just “we hope it doesn’t break”?
2. Developer Experience
- Can a new engineer push code in a day? Or is there a 3-month ramp-up?
- Is onboarding structured—or a Slack thread of outdated notes?
- Are code reviews a ritual—or a “who cares” afterthought?
3. Infrastructure as Code (IaC)
- Is infrastructure managed as code (Terraform, Pulumi)? Or is it “I clicked around in AWS”?
- Can they spin up a new environment in minutes? Or does it take a week?
- Are dev, staging, and prod environments consistent?
4. Data Management
- How’s data stored—structured, or “we’ll figure it out when we need it”?
- Backups? Or “we’re backed up, I think”?
- Is there a data governance policy—or just “everyone has access”?
Actionable Takeaways for Founders and VCs
For Founders:
- Build modular from day one. Spaghetti code is a valuation killer.
- Implement CI/CD and automated tests early. It’s not overhead—it’s insurance.
- Document everything. Code, APIs, infrastructure. Future you will thank you.
- Track cloud costs. $10k/month on a $100 feature is a red flag.
- Audit security regularly. It’s not “if” but “when” something goes wrong.
For VCs:
- Use this checklist. Don’t just eyeball the tech.
- Ask for proof: “Show me how it handles 10x traffic.” Not “we think it will scale.”
- Talk to engineers. The CTO’s spin doesn’t tell the whole story.
- Look for improvement. Are they refactoring? Or just adding features?
- Ask: Will this architecture handle a 10x or 100x business?
Conclusion: The Technical Stack as a Valuation Multiplier
A rare coin’s value is in its details. A startup’s is too. The most valuable companies aren’t just built—they’re crafted. With care, precision, and foresight.
My job? Find those startups where the tech stack is a silent advantage. Where every line of code, every infrastructure choice, every product decision is deliberate. The difference between a good company and a great one? It’s in the nuances. The subtle things that matter most.
Remember: the tech stack is the new GTG 1873 Indian Head Cent. What’s the product built on? That’s the real value. Invest accordingly.
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