Looking for a job

Gustavo Calonico

@gustavocalonico

Message

Rust engineer at Toptal who built Layer 2 infrastructure for Arweave and shipped Solana DeFi systems.

Portugal

Message

What I'm looking for

I'm currently available for B2B or contract engagements, protocol engineering or backend.

At Toptal, I built low-latency REST APIs integrating DeFi protocols on Solana, and created Python bindings that wrap Rust instructions for on-chain execution. I also developed async Python services with containerized deployments and CI/CD.

At Irys.xyz, I was one of the first engineers building Layer 2 protocol infrastructure for the Arweave network. I developed production systems spanning EVM and Solana contracts, and built SDKs that reached 13,000+ downloads on crates.io.

At Ricepool, I built mining pool infrastructure for RandomX and SHA3 cryptocurrencies, including Monero and Tari. I also deployed blockchain nodes and developed monitoring, alerting, and operational tooling for multiple mining protocols.

More recently, at Pensify I built Rust backend services and shipped a calendar and appointment engine for a pension-advice platform. I work across Rust, distributed systems, and blockchain infrastructure, and I'm currently available for B2B or contract engagements.

Experience

Work history, roles, and key accomplishments

Current

Senior Software Engineer

Current

Toptal

Dec 2021 - Present (4 years 10 months)

Senior software engineering role with Toptal, a global talent network, working remotely on client projects.

Senior Backend Engineer

Pensify

May 2026 - Oct 2026 (5 months)

Built backend services in Rust for a Dutch pension-advice platform: REST APIs, async MySQL, and context-generic programming. Shipped a Cronofy calendar/appointment engine and pension-domain logic.

Rust REST APIs Poem OpenAPI MySQL Diesel Cronofy AWS AWS ECS RDS S3 CI CD

Cryptocurrency Quantitative Traders

Jan 2025 - Sep 2026 (1 year 8 months)

Built unified REST API integrating multiple DeFi protocols on Solana with low-latency requirements. Developed async Python services with containerized deployments and CI/CD pipelines.

REST APIs DeFi Solana fastAPI Python Docker AWS GitHub Actions PyO3 Rust

Backend Developer

Guided Ultrasonics

Mar 2026 - May 2026 (2 months)

Rust/SQLx backend fixes for an industrial NDT edge-node product, including Azure CI/CD, SQL migrations, and REST API work.

Rust Sqlx Azure CI CD SQL REST APIs

Cryptocurrency Mining Infrastructure

Ricepool

Mar 2024 - Nov 2024 (8 months)

Built mining pool infrastructure for RandomX/SHA3 cryptocurrencies handling high-throughput workloads. Deployed blockchain nodes and developed monitoring and alerting systems.

Mining Pool RandomX SHA 3 Monero Tari Bitcoin Blockchain Monitoring Alerting

Senior Software Engineer

Deckers US

Sep 2023 - Dec 2023 (3 months)

Rust/Terraform/AWS Lambda infrastructure-as-code for an e-commerce platform build in enterprise retail.

Rust Terraform AWS Lambda Infrastructure as Code

Layer 2 Protocol

Irys.xyz

Dec 2021 - Jul 2023 (1 year 7 months)

Joined as one of the first engineers; built Layer 2 protocol infrastructure for Arweave network from the ground up. Developed production systems using Rust, TypeScript, and Postgres.