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Software & management systems
Admin panels, records, workflows, reports and integrations. Employee management, squads, demands, candidates and screening — whatever your operation needs.
Since 1996 · São Paulo · Brazil
Software, systems and products that ship.
3n20 brings together analysts, tech leads and developers — nearly three decades in banking, industry and utilities. We build online stores, APIs, apps, chatbots and new products from scratch: social platforms, patents, websites with built-in stores, payments and shipping.
Java · SpringNode.jsAngular · ReactKafkaPostgreSQLCloudflareApplied AI
28+Years in critical & enterprise systems
Full-stack devsBack-end, front-end, mobile & integration
Full storePIX, cards, PayPal, shipping, admin, email
Apps & APIsPanels, mobile web, workers & automation
Technologies we use daily
Modern stack for management systems, e-commerce, banking integration and high-performance websites.
Back-end
Java · Spring Boot · NestJS · Node.js · TypeScript · Python · REST · GraphQL
Front-end
Angular · React · HTML5 · CSS3 · JavaScript · PWA · responsive
Data & messaging
PostgreSQL · MongoDB · Redis · Kafka · TypeORM · SQL
Cloud & DevOps
Cloudflare Workers · GitHub Actions · CI/CD · DNS · KV · APIs
Payments & store
PIX · Mercado Pago · Asaas · PayPal · Correios · Uber · Resend
AI & automation
Chatbots · IBM Watson · generative AI · transactional email · analytics
Enterprise
Lotus Notes · SAP · Oracle · legacy integrations · agile squads
Physical product
Prototype · optics · packaging · INPI/PCT patent · supply chain
What we build with you
Six service lines — from template websites from R$ 799.90 to custom landing pages at R$ 999.90 and management systems with dozens of users.
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Full online stores
E-commerce with checkout, automatic PIX, cards, international PayPal, shipping quotes, order panel, transactional email and funnel analytics.
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Websites & landing pages
Professional presence, SEO, bilingual PT/EN, forms and WhatsApp. Catalog of 12 segment templates — from R$ 799.90; custom sites at R$ 999.90.
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Integrations & enterprise
Agile squads, business PIX, account opening, portability, Kafka messaging, CI/CD and systems that cannot go down — large financial institutions experience.
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AI, chatbots & automation
Chatbots, voicebots and cognitive flows (IBM Watson) evolved into applied generative AI — support, screening and operations without noise.
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Innovation, hardware & patents
From idea to shelf: prototype, optics, materials, INPI/PCT patent, packaging, brand and go-to-market. Sensor Tattoo Fix is the live case.
Portfolio & cases
Products, enterprise systems, stores and delivered websites — a real development portfolio.
Product · patent
Sensor Tattoo Fix
Optical lens for smartwatches on tattooed skin. Patent pending, production, official store, PIX/cards/PayPal, admin, Mercado Livre, Shopee, Amazon and international shipping.
StoreMLShopeeAmazonPayPal INT
View product
E-commerce · ops
Sensor Tattoo Fix store
Full stack we replicate for clients: checkout, Cloudflare Worker, KV, labels, shipping, orders, Resend email and admin panel.
Management · enterprise
Squad management system
NestJS + Angular + PostgreSQL panel for professionals across every tech profile — squad intake, screening, HR and coordination at enterprise scale.
- DemandsSquad intake, grade, profile and status
- ProfessionalsEvery tech profile — dossier, screening and approval
- UsersProfiles, authentication and settings
- EmailAutomatic notifications for HR and coordinators
Websites · 12 segments
3n20 template catalog
Auto shops, healthcare, legal, food, gyms and more — from R$ 799.90, live within 48 hours after the brief is approved.
View catalogLanding · services
Recupera Tributos
Specialized team for tax credit recovery — analysis and recovery of overpaid or improperly charged taxes, with landing page and lead capture.
Website · consulting
ES Sports Consulting
Sports consulting for athletes at every level and category — bilingual site, digital presence and service offering for professionals and amateurs.
Professional websites
12 templates ready to customize
Pick a layout, we adapt your brand, copy and WhatsApp. Delivery within 48 hours — ideal for local businesses, clinics and offices.
Templates from R$ 799.90 · custom R$ 999.90 · delivery within 48 hours
Demo
Visual demo · content and identity are customized in the real project.
How we work
Same method for software, store or physical product — validate, build, operate.
01 — Understand
Problem & scope
Initial call, requirements, timeline and budget. No empty jargon: what needs to work on Monday.
02 — Build
Iterative development
Code, integrations, tests and deploy. We use AI and modern tools to move fast without sacrificing quality.
03 — Protect & patent
IP when it matters
For inventions and physical products: technical drawings, reports, INPI/PCT filing and protection strategy — as with Sensor Tattoo Fix.
04 — Operate
Delivery & support
Launch, training, monitoring and evolution. A store that sells, a system the team uses, a site that converts.
Featured case
Sensor Tattoo Fix — product + digital ops
One portfolio project — proof we do end-to-end, not just code.
Millions of tattooed people lose heart rate and workouts on smartwatches. We built an optical lens with patent, production, full e-commerce and six sales channels.
- EngineeringOptics, materials, 30+ models
- DigitalCheckout, admin, analytics, API
- OperationsShipping, email, marketplaces, INT
FAQ
Does 3n20 only make the Sensor Tattoo Fix lens?
No. 3n20 is a software house — management systems, online stores, websites, integrations and AI. Sensor Tattoo Fix is one portfolio product: we developed the optical lens, patent, digital operations and store, but that is only part of what we do.
Can you build a full online store for my business?
Yes — checkout, PIX, cards, PayPal, shipping, order panel, email and admin. Same stack validated on the Sensor Tattoo Fix store.
What about the R$ 799.90 template websites?
Yes. Pick one of 12 catalog models — we customize your brand, copy and WhatsApp and publish. From R$ 799.90.
How long for R$ 999.90 websites?
Up to 48 hours after the brief is approved and materials are sent (logo, copy and photos). May vary with revisions and content volume.
Do you build internal management systems?
Yes — records, workflows, panels, reports and integrations. Experience with squad systems, HR and enterprise operations.
Let's build something together?
Website, store, management system, integration or new product — initial chat with no commitment.
Contact
Tell us what you need — we reply within a few hours.