Currently at Trace Finance · São Paulo, Brazil

Jefter Viana

Senior Software Engineer · Backend

I build mission-critical financial systems: ledgers, payments and regulatory reporting.

Get in touch
Jefter Viana

About

I'm a backend software engineer with almost 6 years of experience in mission-critical financial systems. I've worked on payments, cards, credit, fraud prevention and digital assets, always focused on scalable and resilient solutions, mostly on AWS.

I look for the solution that best fits the real problem, not the most complex one. At Liqi, for example, I helped consolidate Lambda functions into a monolith and migrate from DynamoDB to a relational database, cutting infrastructure costs by at least 40%.

Payments
Pix, TED, boletos, CNAB and Open Finance
Cards & Credit
Card processing and secured lending
Fraud & Identity
Fraud prevention, KYC, OTP, authorization and IAM
Digital Assets
Tokenization and crypto as a service
Ledger & Regulatory
Financial ledger and regulatory reporting (PSAV)

Experience

  1. Trace Finance · Senior Software Engineer

    Built the financial ledger that backed the PSAV license.

    Feb 2026 — present

    • Built an event-based, append-only, immutable financial ledger that met the regulatory requirements for the PSAV license.
    • Developed a reconciliation engine across the system, bank statements and on-chain movements.
    • Sole engineer of the Finance & Accounting squad, since day one.
    • Algorithms to create, validate and translate regulatory reports: DeCripto, e-Financeira, ACAM212, IN188 and MTL.
    • On-chain integrations with Etherscan, Tronscan and Helius.
    • PostgreSQL views and routines that automate reconciliation in the data layer itself.
    • PostgreSQL
    • Etherscan
    • Tronscan
    • Helius
    • BigQuery

  2. Liqi Digital Assets · Senior Software Engineer

    Cut infrastructure costs by at least 40% and built KYC from scratch.

    Jul 2025 — Jan 2026

    • Built a KYC solution from scratch, sized for at least 3,000 validations on day one.
    • Consolidated Lambda functions into a monolith and migrated from DynamoDB to a relational database: at least 40% cost reduction.
    • Integrations with IDWall and BigData Corp for customer validation and identification.
    • Evolved the asset tokenization services, including integrations with B3.
    • Infrastructure services for digital asset custody on the Crypto as a Service team.
    • AWS Lambda
    • DynamoDB
    • PostgreSQL

  3. Paag · Senior Software Engineer

    Built PAAG-ID's SMS and email OTP from scratch.

    Nov 2024 — Jul 2025

    • Helped create PAAG-ID, an SDK-based sign-up and login product that reuses already-validated data.
    • Built the SMS and email OTP system from scratch, with expiration and attempt control.
    • Geolocation system for security and fraud prevention.
    • Evolved the anti-fraud platform with per-user risk scores and interactive dashboards.
    • Anti-fraud
    • OTP
    • KYC

  4. Linker · Software Engineer

    Built secured lending on top of a state machine.

    Jul 2022 — Nov 2024

    • Built the secured credit service, a state-machine-based microservice.
    • Worked across four teams: OpenAPI, Cards, Onboarding and Bank Slips, focused on root-cause bug fixing and building new features.
    • Pix transfer endpoint that automatically creates Pix keys.
    • Batch payments with CNAB files.
    • Launch of a new card model with credit function.
    • Permission control with AWS Cognito.
    • Pix
    • CNAB
    • AWS Cognito

  5. PicPay · Junior Software Engineer

    Automated domestic and international TED transfers.

    Jan 2022 — Jul 2022

    • Backend APIs and services for the social network of a new investment brokerage product.
    • Engine that automates domestic and international wire transfers.
    • Python
    • FastAPI
    • Kafka
    • Redis
    • Neo4j
    • MongoDB

  6. Razy Corretora de Seguros · Software Development Intern

    Built a CRM from scratch that distributes leads automatically.

    Feb 2021 — Jan 2022

    • Built from scratch a CRM that distributes leads among sales consultants through a load-balancing queue.
    • Python
    • PHP
    • PyQt5
    • AWS EC2
    • AWS RDS

Services

How I can help your team or your product.

  1. API Development

    Secure, well-documented REST APIs, ready to scale.

    Pix endpoint with automatic key creation (Linker)

  2. Backend Architecture

    Architecture design and review sized to the real problem.

    −40% infrastructure cost by consolidating Lambdas (Liqi)

  3. Financial Systems

    Reliable ledgers, reconciliation and regulatory reporting.

    Ledger that backed the PSAV license (Trace Finance)

  4. Identity & Fraud Prevention

    Secure onboarding without hurting conversion.

    KYC built from scratch, ready for 3,000 validations on day one (Liqi)

  5. Technical Consulting

    Architecture and code reviews, technical decisions and team support.

    Root-cause bug fixing and new features across four teams (Linker)

Have a project in mind?

Let's talk

Education & Certifications

Education

  • Associate Degree in Systems Analysis and Development

    Universidade Paulista · 2020 — 2021

Certifications

  • AWS CertifiedIn progress

    Amazon Web Services

Contact

Let's talk?

Have a project, an opportunity or an idea? Pick the channel you prefer.

  • Available for consulting and software development
  • I reply within 24h
  • São Paulo · GMT-3