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D MallowsDM

D Mallows

Développeur Fullstack

600 €/jour
Guingamp, FR
3-7 ans

Délai de réponse moyen : 1h

À propos de D

I fix systems that are collapsing under their own weight.

Recent projects:

1. I replaced a fragile Node.js image stack with a go-based transcoding cache and minimal dependencies (ipfs-lite, libvips and ffmpeg). Features include:
  • Animated GIF → MP4 conversion
  • Prioritising of requests to reduce latency
  • Multiple IPFS gateways with direct IPFS interaction as fallback – no need for extra IPFS gateway
2. I wrote an extension for PostgreSQL to handle 256-bit integers
  • Hex representation
  • Summation, addition, comparison operators
  • Uses AVX2 for optimised conversions.
  • Similar plugin written for SQLite.
3. An extractor for freezer files from go-ethereum.
  • Written in zig with single dependency.
  • Full NFT ownership list in ~20 minutes.
  • Optimised server based on Radix Tries.
  • Impact: ~0.5ms vs 10s latency (20000x)

4. Major cleanup of a solidity smart contract.
  • Pushing the single contract size limit with massive gas fees.
  • Identified and fixed multiple potential reentrency attacks.
  • Reduced storage by passing data and working against a hash.
  • Added gas-reducing safety-optimized batch calls.
  • Simplified maths using fixed-point arithmetic.
5. WebAssembly module written in Zig.
  • Deployed in Postgres, on Frontend and on Backend (for Server-Side Rendering).
  • Updates reactive svelte values.
  • All memory allocation up front.
  • Custom binary file format enables loading straight into memory.
  • Before: 200ms UI jank; after: overlooked by the profiler.
My most recent work has been around Ethereum-centred projects, but the skills I bring are universal.
  • Anglais

    Bilingue ou natif

  • Français

    Notions

En télétravail uniquement
Travaille majoritairement à distance

Expériences

  • DPWM Informatique
    Développeur full-stack
    HIGH TECH
    janvier 2021 - Aujourd'hui (5 ans et 5 mois)
    Guingamp, France
    I’ve worked on a long list of projects, including:
    • Beautifully typeset hundred-plus-page programatically-generated reports using Python, SQLite and ConTeXt.
    • An invoicing app to be deployed on the Sandstorm platform
    • A 10kB Webassembly module that replaced a bug-ridden 2MB javascript bundle, vastly improving page load and customer UX.
    • A PostgreSQL extension using C and Zig to handle huge numbers.
    • Low-latency in-database typescript code to replace high-latency application code.
    • An SQLite extension to provide functions related to big numbers.
    • Writing and testing smart contracts for Ethereum.
    • A high-concurrency image and video cache and transcoding pipeline using Go, FFmpeg and ipfs-lite.
    • Automatic document generation and low-code solutions for a small animal charity.
    PostgreSQL Ethereum Python Solidity Typescript
  • CarrHolm
    Accounts and Administration
    SECTEUR MÉDICAL
    juillet 2012 - août 2020 (8 ans et 1 mois)
    Prestatyn, Royaume-Uni
    I held several positions at a small retirement home. I was responsible for documentation, compliance, and employee integration. I was also responsible for all computer and telephone systems on a limited budget. I also was able to experiment with improved workflows in relation to staff rostering.
    Writing Ocaml Python Webmarketing
  • The Universiy of Edinburgh
    Développeur
    CENTRES DE RECHERCHE
    juillet 2010 - juillet 2012 (2 ans)
    Edinburgh, Royaume-Uni
    I undertook a series of interesting summer projects under a researcher at the University of Edinburgh. I worked on the RIVET analysis framework and YODA analysis objects, mainly in Python and C++. I developed Python bindings for YODA. I significantly improved the performance of histogram binning; the approach I adopted is still used in production today. I also worked on a scientific plotting tool.


    Python C++ XML

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Formations

  • Physics (MPhys)
    University of Edinburgh
    2012
    Physics with Integrated Masters. Final project studied Statistical Physics models on random undirected graphs.

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