Juno Vale

Distributed systems engineer. Ingestion pipelines and event-sourced inventory on the BEAM.

Porto (remote)GitHubStack Overflow

2025

Talk

NIFs Without Tears

  • Three rules that make a Rust NIF an ordinary engineering tradeoff
  • Measured a dirty-scheduler violation live and watched latency collapse

Talk

Backpressure in Practice

  • Four honest answers to an overloaded queue, and how to choose between them
  • Why concurrency: is a policy setting wearing a performance costume

2024

Project

Tacto

  • Terminal client for reading event streams live
  • Renders a supervision tree next to the stream it is producing

2023

Position

Staff Engineer · Ledgerbeam

  • Led the move from mutable stock levels to an event-sourced movement stream
  • Rebuilt ingestion on Broadway; sustained a 40x burst without shedding orders
  • Introduced property testing across the parsing and merging seams

Project

Ledgerbeam

  • Event-sourced inventory for mid-size distributors
  • Rebuilt stock projections as a fold over movements, deleting the nightly reconciliation job
  • Ingestion pipeline sustained a 40x burst without shedding orders

2017

Position

Senior Engineer · Meridian Payments

  • Settlement pipeline processing roughly 2M transactions a day
  • Cut reconciliation defects by making retries idempotent at the boundary

2013

Education

BSc Computer Science · University of Porto

  • Final year project: a consensus visualiser for teaching Raft

Open source