[Position]: AI Full Stack Developer Developer & Security Engineer
[Programming Languages]: TypeScript, Python, C#/.NET, React/Next.js, Node.js, Go, Rust, React Native,Flutter
[Years Experience]: 5 years.
[Previous Projects]: https://github.com/Nahusenay-S
https://nahusenay-simegn.vercel.app/
[Availability]: Open to all types of collaborations from long-term partnerships to one-off projects.
72+ hrs/week availability
[Other Info]: I build fast, scalable, and production-grade AI agent platforms, automation systems, and high-performance bots
Strong experience developing complex AI solutions using React.js, Node.js, and Python. Extensive background creating various enterprise-grade applications with C# and the full .NET ecosystem (ASP.NET, VB.NET included).
Passionate about performance, scalability, clean architecture, and tackling challenging problems across web, mobile, desktop, and low-level systems
Freelancer Offers
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Web developer/designer
check out my portfolio
https://sajad.dev
[Position]: Senior Full-Stack Engineer / Frontend Architect
[Programming Languages]: TypeScript, React, Next.js, Angular, Python (FastAPI, Django), Node.js, PostgreSQL, Docker, GCP/AWS
[Years Experience]: 10+ Years (Senior / Staff Architect)
[Previous Projects]:
• https://mohammadasjad.com (Portfolio)
• https://github.com/asjadaugust (GitHub)
• Lead Architect for KLM Royal Dutch Airlines Ground Business Platform (Mission-critical flight & airport operations)
[Availability]: Immediate | Remote | Contract, Freelance & Full-Stack Projects
[Other Info]:
Specialized in high-performance web apps, scalable APIs, modern frontends, and AI agent integrations. Reliable delivery, clean architecture, and clear communication. DM me to discuss your project!
[Position]: Lead Scripter / Junior
[Programming Languages]: LUAU, C#
[Years Experience]: 3 to 4 years.
[Previous Projects]: Dm me for active games I've worked on and sold to studios
[Availability]: Everyday
[Other Info]: I'm verified on Roblox with a blue checkmark, if it helps.
[What I'm looking for]: Team of devs or a dev to work closely with, sharing ownership or good pay, whatever works for you.
I usually go with a VSCode, Rojo workflow, might incorporate AI if we need to reach goals fast. I know how to use it well along with my scripting.
I can work with existing codebase and figuring out bugs.
I might not be in the server when you read this, just reach out if you're interested
3D artist/designer of game assets or renders
N/A
[Position]: Backend Developer — Java / Spring Boot, API bug fixing & REST API development
[Programming Languages]: Java 17, SQL, TypeScript, JavaScript (Vue 3)
[Years Experience]: 7 months, production ERP (Java/Spring Boot, incident resolution, SQL diagnostics)
[Previous Projects]: Multi-tenant financial management API — 34 endpoints across 7 controllers, RBAC with 5 roles, per-company tenant isolation, JWT in HttpOnly cookies, Flyway migrations, soft delete for auditable history. github.com/MatheusCristophi/ERP-Financeiro-Backend · github.com/MatheusCristophi/ERP-Financeiro-Fontend. Production ERP: log and data-driven diagnosis, root-cause tracing, fix and ship. Commit explains what was actually wrong, not a try/catch on the symptom.
[Availability]: Weekdays 18h–23h UTC-3 (overlaps US East afternoons) and weekends, up to 25h/week. Reply within 3h. Async and text-first — written English only, so nothing gets lost in a call.
[Other Info]: Fixes: 500s, NullPointer, unhandled exceptions, bogus 401/403, JWT and Spring Security misconfig, broken role checks, N+1 and missing indexes, data repair via SQL (PostgreSQL, Firebird). Builds: REST APIs with Spring Security, JWT, RBAC, Flyway migrations, DTO layer, third-party integration, Docker, JUnit/Mockito. Written scope and deadline before any code; fixes 50% on approval / 50% on delivery, builds 40/40/20. Diagnosis $30–40/h (1h min, quote before changes). APIs from $350. github.com/MatheusCristophi · linkedin.com/in/matheuscristophi · DM or matheuscr909@gmail.com
[Position]: Backend Developer — Java / Spring Boot, API bug fixing & REST API development
[Programming Languages]: Java 17, SQL, TypeScript, JavaScript (Vue 3)
[Years Experience]: 7 months, production ERP (Java/Spring Boot, incident resolution, SQL diagnostics)
[Previous Projects]:
- Multi-tenant financial management API — 34 endpoints across 7 controllers, RBAC with 5 roles, per-company tenant isolation, JWT in HttpOnly cookies, Flyway migrations, soft delete for auditable history. github.com/MatheusCristophi/ERP-Financeiro-Backend · github.com/MatheusCristophi/ERP-Financeiro-Fontend
- Production ERP: log and data-driven diagnosis, root-cause tracing, fix and ship. Commit explains what was actually wrong, not a try/catch on the symptom.
[Availability]: Weekdays 18h–23h UTC-3 (overlaps US East afternoons) and weekends, up to 25h/week. Reply within 3h. Async and text-first — written English only, so nothing gets lost in a call.
[Other Info]: Fixes: 500s, NullPointer, unhandled exceptions, bogus 401/403, JWT and Spring Security misconfig, broken role checks, N+1 and missing indexes, data repair via SQL (PostgreSQL, Firebird). Builds: REST APIs with Spring Security, JWT, RBAC, Flyway migrations, DTO layer, third-party integration, Docker, JUnit/Mockito. Written scope and deadline before any code; fixes 50% on approval / 50% on delivery, builds 40/40/20. Diagnosis $30–40/h (1h min, quote before changes). APIs from $350. github.com/MatheusCristophi · linkedin.com/in/matheuscristophi · DM or matheuscr909@gmail.com
Java / Spring Boot — API bug fixing & REST API development
500s, hanging endpoints, slow queries, broken auth? I read the logs, trace the flow and fix the root cause — not a try/catch on the symptom.
Production ERP background, where downtime costs money by the minute. Diagnosis through logs and data, fix, and a commit that explains what was actually wrong.
Fixing & maintenance:
- 500s, NullPointer, unhandled exceptions
- Endpoints returning bogus 401/403
- JWT and Spring Security misconfiguration, broken role checks
- N+1 queries, missing indexes, slow endpoints
- Data inconsistency repair and recovery via SQL (PostgreSQL, Firebird)
Building:
- REST APIs with Spring Security, JWT and RBAC
- PostgreSQL with JPA/Hibernate, versioned Flyway migrations, DTO layer
- Third-party API integration, Resilience4j rate limiting
- Vue 3 + TypeScript frontend wired to your API
- Docker environment, JUnit/Mockito tests
How I work:
- Written scope and deadline before a single line of code — in and out of scope, in writing
- Fixes: 50% on quote approval, 50% on delivery. Builds: 40% on approval, 40% at first working deploy, 20% on delivery
- Everything over text, async-friendly. Written English only, so nothing gets lost in a call.
- Repo with clean commits and README, reply within 3h
Overlaps full US business hours (UTC-3, until 6pm local).
Projects: multi-tenant financial API (34 endpoints, RBAC 5 roles, JWT HttpOnly cookies, Flyway, soft delete).
Java 17, Spring Boot, Spring Security, JPA/Hibernate, PostgreSQL, Firebird, Flyway, Resilience4j, Vue 3, TypeScript, Docker, Git.
github.com/MatheusCristophi · linkedin.com/in/matheuscristophi · DM or matheuscr909@gmail.com
Diagnosis $30–40/h (1h min, root cause and fixed quote before any change). APIs from $350, quoted per scope. Send the endpoint list or the stack trace and I'll come back with quote and deadline.
Hello, I'm interested in the graphic design opportunity. Kindly reach out to me on Telegram @physceX, as I'm currently unable to send you a DM. I'd love to discuss the job and the possibility of working with you long-term. Thank you.
[Position]: Web Developer
[Experience]: 3 years building websites
[Education]: Second-year undergrad at Texas Tech
[Previous Work]: (These are demos)
https://cognir-research.web.app
https://sandbox-built.web.app
[What I offer]: Simple, clean websites for $59 (Amazon digital gift card)
[How it works]:
You tell me what you need
I build the full site
I send you screen recordings of the entire working site so you can review everything
You only pay if you’re happy with it
If you’re not happy, no payment, no pressure
Once paid, I handle deployment + domain registration. The site goes live and stays up unless you later ask me to take it down
[Availability]: Flexible, can start quickly
[Other]: I keep things straightforward. No fluff, no pressure. Just a clean site you can actually use.
DM me if you want one.
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