Loading Complex Problems
We turn complex ideas into high-performance software. Cutting-edge technology for companies that aim for market leadership.
Everyone's building with AI now. We do too—aggressively. The difference is knowing where it stops working. That's where we start.
Fintech, logistics, B2B platforms in 5+ countries
ENGINEERING JUDGMENT
The promise of AI-first development is seductive: faster, cheaper, scale with vibes. But your fintech platform, logistics network, or B2B system isn't a chatbot. It's your business—and when complexity breaks, you need judgment, not guesses. 300 Software is the team that knows exactly where AI works brilliantly and where it stops. We use AI aggressively as an accelerator. But we deliver with engineering rigor.
Founded in 2017 by Guilherme Mello (18 years engineering, EMBA from IESE), 300 Software is a lean team of senior professionals solving the problems that matter. We've spent years building—and rebuilding—mission-critical systems for Everchain (fintech), BusUp (mobility), Frontier Airlines, and others. No commodity solutions. No overscoped roadmaps. Just solid engineering for the complexity that counts.
See how we work
HOW WE HELP
We meet you where complexity lives. AI as acceleration, engineering judgment as the product.
Before code, there's judgment. We audit systems, design for complexity, and guide you through architectural decisions. Discovery to detailed roadmap.
Learn more
Make your systems talk. We unify ERPs, CRMs, and legacy software in a single automated flow, eliminating manual barriers and technical debt.
Learn more
AI-augmented delivery of mission-critical systems. Fintech platforms, logistics networks, B2B infrastructure—built with precision where complexity counts.
Learn more
Aging systems slowing you down? We modernize architecture, migrate safely to cloud, and refactor with precision—keeping complexity under control.
Learn more
Scale your technical depth with senior engineers embedded in your operations. We move at your pace, speak your language, own the outcomes.
Learn moreAt 300 Software, we combine technical depth with speed. Our senior team moves decisively—understanding complexity fast, building solutions that last, shipping outcomes that matter. No bloat. No buzzwords. Just solid engineering.
Talk to an engineer
Fintech, logistics, B2B platforms. We've built and rebuilt these systems. We understand the edge cases, regulations, integrations that actually matter.
We move fast because we're focused. Senior team, clear priorities, AI as acceleration. You ship results in weeks, not quarters.
Systems handling millions of transactions. Legacy migrations without breaking business. Real-time data pipelines. This is what we're built for.
The right architecture matters. The right tech stack matters. The right tradeoffs matter. We make decisions with precision and accountability.
AI does what AI does well. We handle the rest—with rigor, judgment, and accountability that keeps your systems running strong.
EverChain has enjoyed a successful partnership with 300 Software since 2020, focused on implementing new software products and ongoing maintenance. The team is highly productive and internal stakeholders have been particularly impressed with their knowledge, efficiency and experience.
Our experience with the system developed by 300 Software has been very good. The system is very reliable and intuitive, greatly assisting in the team's adoption and adaptation. It met our needs as we expected and post-implementation support has been excellent.
I had the opportunity to work with both Guilherme and Mario as part of the same development team — together they were pillars. They consistently demonstrated technical competence, ownership, and accountability in delivering sprint commitments. As a team, they brought both technical depth and professionalism to the organization, and I would confidently recommend them for environments that value reliability, collaboration, and strong delivery outcomes.
Senior professionals solving high-stakes problems—because complexity deserves real engineering.
View full team
Founder & Chief Executive Officer
Chief Financial Officer
Frequently Asked Questions
We work with the most robust stacks on the market, including JavaScript (React, Node.js, Vue), Python (Django, Flask), Java, .NET, as well as cloud technologies such as AWS, Azure and Google Cloud Platform. We select the ideal technology based on your project's needs.
We conduct an initial immersion (Discovery) to understand the project scope. Based on that, we present a detailed schedule and transparent quote. We work with agile methodologies (Scrum/Kanban) to ensure continuous delivery and full visibility of progress.
Yes. We offer support and evolution packages (SLA) to ensure your software continues to work perfectly, receiving security updates and new features as your business grows.
Absolutely. In custom software development contracts, all source code and documentation generated belongs 100% to the client after delivery and project completion. We guarantee this in the contract.
Yes, we are experts in system integration. We analyze your current infrastructure and develop APIs and middlewares to connect your legacy systems with new digital platforms securely and efficiently.
Timelines vary by scope. A focused MVP typically takes 6–10 weeks, while a full platform with multiple integrations can take 3–6 months. We define a realistic schedule during our initial Discovery phase so you have clear milestones from day one.
We work with organizations solving genuinely complex problems. That's usually enterprises and scale-ups with mission-critical infrastructure, real data volumes, or regulatory complexity. If you're building with commodity solutions or AI-first, we're probably not your fit. If you're solving a real engineering problem, let's talk.
We price based on complexity and value, not just headcount or hours. Fixed-price works for well-scoped engagements with clear requirements and low risk. Time & materials suits evolving platforms or ongoing technical leadership. We recommend the right model after understanding scope, risk, and your business outcomes.
Yes. We offer a paid Discovery phase where we map your requirements, define the architecture, and deliver a detailed roadmap. It's a low-risk way to experience how we work before committing to a full project.
Yes. Our team operates fully in English and Portuguese. We have delivered projects for clients in the United States, Europe, and Latin America, and our entire delivery process — documentation, sprint reviews, and communication — runs comfortably in either language.
We follow agile sprints with regular reviews where you see working software, not just status reports. Day-to-day communication runs through Slack or your preferred tool, and all tasks are tracked in ClickUp or Jira. You always know what is being built and what comes next.
You get a dedicated Squad — a cross-functional team (developer, QA, tech lead) allocated exclusively to your project. We do not share resources across multiple clients simultaneously. Your squad becomes a direct extension of your team.
Scope changes are a natural part of software development, and we plan for them. New requirements are evaluated, prioritized, and incorporated into the next sprint or documented as a change order. We never begin out-of-scope work without your explicit approval.
Web Development
Mobile App
IT Consulting
Complex Systems
Innovation
API integration
Web Development
Mobile App
IT Consulting
Complex Systems
Innovation
API integration
Web Development
Mobile App
IT Consulting
Complex Systems
Innovation
API integration
