Hire the Best Software Development Freelancers
in Brazil

I’m a Software Engineer with strong experience in Python, JavaScript, and full-stack web development, focused on building scalable, high-performance applications. I specialize in backend development with Flask, REST APIs, and MySQL, along with modern frontend solutions using HTML, CSS, and dynamic JavaScript interfaces. My work includes API development, database design, automation scripts, and system integration, as well as handling complex workflows such as audio processing, multimedia pipelines, DICOM processing, and data transformation. I’ve also worked with tools and libraries like PyQt / PySide and ffmpeg, giving me a versatile skill set across both web and desktop environments. I’m experienced in debugging, performance optimization, and clean architecture, ensuring that every solution is not only functional but also maintainable and efficient. I also leverage advanced AI-assisted development tools (including Claude Max) to accelerate delivery, improve code quality, and explore optimized solutions when tackling complex problems. Whether it's building a system from scratch, improving an existing codebase, or solving critical bugs, I focus on delivering reliable, production-ready results. If you’re looking for a developer skilled in Python, Flask, JavaScript, APIs, MySQL, automation, and scalable systems, I can help turn your ideas into solid, working software.

It was the most important moment of my 13+ years of career. It was when I realized that there is always a trade-off in technology. You have to do something intentionally bad in order to succeed as a Small Medium Business in the Digital Transformation. And 70% fail because they insist on doing this very thing well. A while back, when I finally landed a job in a corporation, I was excited that I was going to use state-of-art technology. But, one of my first features immediately added some bugs. As I fixed those bugs, I introduced another, but also other bugs started to pop up caused by previous developers. In laymen terms, it is like a Rubik’s cube. As you carry on assembling the second face, you may accidentally mess up the first bit. It wasn’t like that when I started my career in technology in the civil service a long time ago. Yes, I was frustrated because we used old boring technology. But, we didn’t have to put out the fire all the time because that limited technology prevented us from getting in this position. Coincidence or not, the easiest way to solve the Rubik’s cube is putting constraints. If you move towards, you have to move backwards at some point. Fast forward to nowadays, some of my clients want to create highly customized User Experience. As the project starts to grow, hyper customization introduces more complexity. Then, you make a small change and get unexpected results. You didn't account for all the complex consequences. And this happens again and again, and you can’t avoid it. The software had become brittle. You start to miss deadlines or have to hire more developers to fix cracks faster, and eventually I get hired. That’s the time I have the hard talk: don’t bite more than you can chew, stop chasing the perfect User Experience (good User Interface is not a problem though) with a small team. If a BigTech didn’t have to hire thousands of engineers to provide that, they certainly wouldn’t. Anyway, User Experience is only noticed by B2C clients, and this is where Big Techs thrive. In B2B or internal tool software, who pays for the software won’t even use it. Hey, my name is João, I’m a software architect and developer, feel free to send me a message asking how I can make your business grow. What technologies do I work with? The simple ones: HTML, CSS, Bootstrap, Bash, XML, PostgreSQL, Apache Camel, Apache Knowledge Is Everything, Keycloak. If you need a hypercustomized solution, I can decently program in Java, Python and JavaScript, though. If you have any doubts, don’t hesitate to contact me.

Senior Full-Stack & AI Engineer (12 years) helping startups and SMBs ship scalable web apps and AI features that actually work in production — not lab demos. My sweet spot is well-scoped, high-leverage work: build the system, harden it, then layer in AI where it earns its keep. My stack: TypeScript, Python, React, React Native, and Electron — deployed via Docker and Terraform on GCP and Cloudflare. Production systems I've shipped currently serve ~800K monthly requests across 10+ live properties. What clients hire me for: - Full-stack delivery — Next.js/React + FastAPI/Flask/Node (TypeScript), clean architecture, scalable APIs. - AI integrations — LLM features (Claude/GPT/Gemini), RAG over your data, agents and agent harnesses, automation pipelines, computer-use, computer vision, AR. - "Make it reliable" — auth, billing, CI/CD, Docker, Terraform, Cloudflare/GCP/AWS — deploys cleanly, stays maintainable. Proof of impact: - Built a RAG logistics platform extracting PDF data at 97% accuracy, cutting manual entry 85%. - Introduced AI-driven TDD workflows that lifted delivery velocity 58% with zero regressions. - Production footprint of work I've shipped: ~800K requests, ~20K unique visitors, ~40K threats blocked monthly — across 10+ live properties. ⚡ Special Offer: Right now I'm offering a limited competitive rate to early Upwork clients. Agency-level engineering at freelancer pricing — before my standard rates lock in.

⭐⭐⭐⭐⭐ Rated API-driven automations that turn busywork into business impact. I connect your tools so your team can focus on what matters. Rapid API integrations. Reliable automations. Real results. Since 2009, I’ve helped companies turn messy, manual workflows into reliable automations. With 70+ successful freelance jobs and 7+ years of fully remote work, I design, build, and ship solutions that save time and scale. What I do best -API integration & process automation (core focus) -No-code/low-code: Zapier, Make (Integromat), Bubble -Scripting: Python & JavaScript for custom logic, webhooks, and ETL -Google Workspace: Google Apps Script, Gmail API, Sheets API, Forms, and cross-platform integrations Typical outcomes -Automate repetitive tasks (lead routing, invoicing, reporting) -Connect CRMs, payment gateways, and SaaS tools into one flow -Replace spreadsheets & copy-paste with robust, auditable pipelines -Build “human-in-the-loop” failsafes and clear run logs Toolbox -Zapier (paths, filters, loops, custom Python) -Make.com (routers, iterators, arrays, webhooks) -REST/GraphQL APIs, OAuth2, web scraping, and Django backends -Bonus skills: C/C++/C#, Java, PHP, HTML5/CSS, MySQL, game dev basics Why clients hire me -Proven delivery: 70+ global projects shipped on time -Clear communication, quick iterations, and long-term maintainability Let’s talk -Share the problem you want to automate and the tools you use—I’ll propose a fast, phased plan (MVP → scale) you can approve and run with.

AI, Data Science, and Full-Stack Development Specialist | 4+ Years of Freelancing Experience I hold a Professional Certificate in Data Science from MIT and am recognized as a Microsoft Innovative Educator Expert (MIEE) with over 30 Microsoft certifications and badges. Over the last four years, I’ve been a dedicated freelancer, helping businesses leverage data-driven insights, machine learning, and robust software solutions to achieve sustainable growth. As the owner of a dev shop, SimpleDev, I lead a team of experts who specialize in crafting high-impact applications, AI-driven systems, and automation strategies. My focus is on delivering results that truly transform how companies operate—whether by building end-to-end platforms, integrating advanced analytics, or optimizing existing processes for efficiency and scalability. Key Services AI & Machine Learning Implementation Data Analytics & Visualization Custom Software Development Process Automation & Optimization Cloud Integration & Deployment If you’re looking to elevate your operations with AI, streamline workflows, or build a robust software solution, let’s connect. I’m here to help you navigate the path to digital transformation—on time, on budget, and with measurable impact.

Hi everyone, I am a freelancer specialized in declarative languages, such as Prolog and its derivations. These programming languages are in general used to solve combinatorial problems related to areas such as Artificial Intelligence (AI) and Operations Research (OR). To solve these problems, mathematical modeling is used, with programming languages and tools like Prolog (and its several branches), PICAT, MINIZINC, OR-TOOLS, Z3 solver, ASP, PULP, etc. I also have some knowledge of other classical programming languages, such as C, V, C++, Python, and others. I find the V programming language really cool! Besides, my hobbies are Linux, small and cheap computers, so I also jumped into the embedded systems area. In addition I can offer you following services։ ☞ Coding and typesetting of documents in LaTeX (containing tables, figures, mathematical symbols, equations, etc.). ☞ LaTeX typesetting & editing of articles, reports, dissertations, doctoral thesis, posters, presentations, CVs, and other documents. ☞ Bibliography management via BibTeX, BiBLaTeX. ☞ Word/Office to LaTeX conversion. ☞ Creation of Beamer presentations in LaTeX. ☞ Writing of mathematical formulas in LaTeX. ☞ Onboarding documents online with LaTeX. ☞ Any other LaTeX work. ☞Technical translations related to CS ☞Based on my background, I can teach you many CS subjects via online classes. If you want to know more about myself: I have an amateur channel on YouTube, search for "Claudio Cesar de Sá" or go directly to: @claudio_sa where I show some of my expertise and hobbies. I usually work upon invitation, so please do not hesitate to contact me!