My story
A little about me.
6
projects shipped
I'm Marcus — a full-stack developer who builds systems that stay up, stay fast, and don't lose money when traffic spikes.
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Demo portfolio — content is illustrative. Yours is built from your real work.
Create yours freeFull-Stack Developer · APIs & Infrastructure
Systems that don't fall over.
APIs, payments, dashboards, migrations — the unglamorous work that keeps businesses running. Here's what that looks like with real numbers attached.
0
Uptime on my microservices architecture
$0
Payments processed with zero errors
0
Records migrated with zero downtime
0
Faster API response times
Selected work
I'd rather show you than tell you.
Each case below tells the full story: the problem, what I did, and the result.
★ Case study 01 · Backend
API Optimization: 89% Faster Response Times
API Optimization: 89% Faster Response Times
Turned a slow API into a speed demon. Performance optimization that saved the company $40K monthly in server costs.
The receipts
How it went down
01 The Challenge
- The e-commerce API was taking 2.4 seconds to respond.
- During peak hours, it would timeout completely.
- Users were abandoning carts.
- The company was spending $40K monthly on servers just to keep it running.
02 The Strategy
- I profiled the entire codebase to find bottlenecks.
- Implemented database query optimization with proper indexing.
- Added Redis caching for frequently accessed data.
- Refactored N+1 queries into batch requests.
03 The Result
- Response times dropped from 2.4s to 280ms (89% faster).
- Server costs decreased from $40K to $12K monthly.
- Zero timeouts during peak traffic.
- Cart abandonment rate dropped 34%.
Fast code isn't about fancy algorithms. It's about finding what's slow and fixing it.
★ Case study 02 · Full-Stack
Real-Time Dashboard: $2M in Prevented Losses
Real-Time Dashboard: $2M in Prevented Losses
Built a system that catches problems before they become disasters. Custom analytics platform that saved millions by detecting issues in real-time.
The receipts
How it went down
01 The Challenge
- The logistics company was losing $500K monthly to operational issues they discovered too late.
- Data was scattered across 12 different systems.
- By the time they noticed problems, trucks were already off-route or shipments were delayed.
- They needed real-time visibility.
02 The Strategy
- I built a custom real-time dashboard that aggregated data from all their systems.
- Implemented WebSocket connections for live updates.
- Created smart alerts that detected anomalies automatically.
- Added predictive analytics to flag potential issues before they happened.
03 The Result
- Caught and prevented $2M in losses in the first year.
- Issue detection time went from 4 hours to 30 seconds.
- Operational efficiency increased 47%.
- Managers saved 15 hours weekly not manually checking systems.
Real-time data isn't just nice to have. It's the difference between reacting and preventing.
★ Case study 03 · Backend
Payment Integration: $8M Processed, Zero Errors
Payment Integration: $8M Processed, Zero Errors
Built the payment system that never fails. Rock-solid integration that processed millions without a single failed transaction.
The receipts
How it went down
01 The Challenge
- The marketplace needed to integrate Stripe, but their legacy system wasn't compatible.
- Previous developers tried and failed - transactions would randomly fail, money would get stuck, and support was drowning in complaints.
- They were losing $50K monthly to failed payments.
02 The Strategy
- I built a robust middleware layer with comprehensive error handling.
- Implemented idempotency keys to prevent duplicate charges.
- Added automatic retry logic with exponential backoff.
- Created detailed logging for every transaction.
03 The Result
- Processed $8M in transactions with zero errors.
- Failed payment rate went from 3.2% to 0%.
- Support tickets about payments dropped 94%.
- The system handled Black Friday traffic (10x normal) without issues.
Payment systems can't be 'mostly working'. They need to be bulletproof. Every. Single. Time.
★ Case study 04 · Database
Database Migration: Zero Downtime, 50M Records
Database Migration: Zero Downtime, 50M Records
Moved 50 million records without anyone noticing. Seamless migration from legacy database to modern infrastructure.
The receipts
How it went down
01 The Challenge
- The SaaS company needed to migrate from their legacy MySQL database to PostgreSQL.
- They had 50M records, 200K active users, and couldn't afford any downtime.
- Previous attempts caused outages and data loss.
- The CTO was terrified of trying again.
02 The Strategy
- I designed a zero-downtime migration strategy.
- Set up dual-write system to keep both databases in sync.
- Implemented gradual rollout - migrated users in batches of 1,000.
- Created automated rollback procedures in case of issues.
03 The Result
- Migrated all 50M records with zero downtime.
- Users didn't notice anything changed.
- Data integrity was 100% - not a single record lost or corrupted.
- Query performance improved 67% on the new database.
The best migrations are the ones users don't notice. Boring is beautiful when it comes to infrastructure.
★ Case study 05 · DevOps
Automation Pipeline: 40 Hours Saved Weekly
Automation Pipeline: 40 Hours Saved Weekly
Automated the boring stuff so the team could build. CI/CD pipeline that made deployments effortless and error-free.
The receipts
How it went down
01 The Challenge
- The development team was spending 40 hours weekly on manual deployments.
- Each deploy took 2 hours and required 3 people.
- Deployments often broke production.
- They could only deploy on Fridays, which meant waiting a week to fix bugs.
02 The Strategy
- I built a complete CI/CD pipeline from scratch.
- Automated testing, building, and deployment.
- Set up staging environments that mirrored production.
- Implemented automated rollbacks if health checks failed.
03 The Result
- Deployment time went from 2 hours to 5 minutes.
- Team saved 40 hours weekly.
- Deployments increased from 1 per week to 20+ per week.
- Production incidents dropped 78% due to automated testing.
Automation isn't about replacing people. It's about freeing them to do work that actually matters.
★ Case study 06 · Architecture
Microservices Architecture: 99.99% Uptime
Microservices Architecture: 99.99% Uptime
Rebuilt a monolith into a system that never goes down. Architecture redesign that made the platform scalable and reliable.
The receipts
How it went down
01 The Challenge
- The monolithic application was crashing weekly.
- When one feature broke, the entire platform went down.
- Scaling was impossible - they had to scale everything even if only one feature needed more resources.
- Uptime was 97.2%.
02 The Strategy
- I redesigned the architecture into microservices.
- Split the monolith into 12 independent services.
- Implemented service mesh for communication.
- Added circuit breakers to prevent cascading failures.
03 The Result
- Uptime increased from 97.2% to 99.99%.
- Platform handled 5x traffic growth without infrastructure changes.
- Deployment speed increased 10x - teams could ship independently.
- When issues occurred, they affected only one service instead of everything.
Microservices aren't about being trendy. They're about building systems that can grow and fail gracefully.
How I can help
Ways to work together.
What I can take off your plate as a Full-Stack Developer.
01Start here
Feature build
A production-ready feature, from database to UI.
- Scoped spec before any code
- Tests and monitoring included
- Deployed to your infrastructure
If this is youTeams with a roadmap and not enough hands.
02
Performance rescue
Slow app? Find the bottleneck and kill it.
- Profiling and diagnosis
- Query & caching optimization
- Before/after benchmarks
If this is youProducts losing users to load times.
03
Fractional engineering
Senior engineering muscle, a few days a week.
- Architecture reviews
- Code quality & mentoring
- On call for the scary stuff
If this is youStartups not ready for a full-time senior hire.
What people say
Don't take my word for it.
★★★★★
“Marcus migrated 50 million records without a second of downtime. Our previous attempt took the site down for a day.”
SMSofia Martins
CTO, logistics platform
CTO, logistics platform
★★★★★
“He rebuilt our API and response times dropped 89%. Churn from performance complaints basically vanished.”
JWJames Whitfield
Head of Product, SaaS
Head of Product, SaaS
★★★★★
“The payment integration has processed $8M and never once paged us at 3am. That's the review.”
ABAisha Bello
COO, marketplace startup
COO, marketplace startup
How I work
Simple. Fast. Sharp.
01
Tell me the problem
We start with a short call or message about what you need and when you need it.
02
I do the work
You get progress updates as I go — no chasing, no surprises.
03
You get results
Delivered, revised until you're happy, and documented so it keeps working.
Let's talk
Ready to get started?
Tell me what you're working on and where it's stuck. I'll get back to you with how to move it forward.