A life in software.
I started building for the web in 1998. I've been building applications and connecting systems ever since.
I'm Justin Silver, known online as doublesharp. I build web applications, design technical architecture, and connect business systems. I've run DoubleSharp Consulting since 2005.
01 / Selected chapters
The story so far.
Applications, integrations, and independent projects.
Now / Current work
Rebel Dividends
My current work with Rebel Dividends includes Rip.xyz and Ensemble.io: tokenized vault strategies and the applications and infrastructure around them.
2017 onward / Blockchain applications
Web3 & blockchain applications.
Since 2021, I've focused on EVM development. My work with the Paintswap team spans its NFT marketplace, Estfor Kingdom, Paintswap VRF, and the Sonic Airdrop NFT & Order Book, alongside art NFT deployments on Fantom and Sonic.
I've also developed for Flying Tulip and provided smart contract audits and security reviews.
Earlier, in 2017–2018, I worked with Syscoin and Blockchain Foundry, the team behind the Blockmarket decentralized marketplace.
2012–2024 / Product teams
Software outside the office.
As CTO at RovAir, I worked on on-demand mobile broadband. At Secret Party, where I was CTO from August 2016 to September 2024, the focus was event management: helping hosts create event pages and manage their guests.
Since 2005 / Independent practice
DoubleSharp & enterprise systems.
I founded DoubleSharp in 2005 after working as a technical lead at Williams-Sonoma. Consulting brought work with Bell Helicopter, Riverbed, Scientific Learning, AAA, and Palo Alto Networks: business applications, cloud architecture, and integrations between systems that needed to share information.
1998–2004 / The early web
Websites, networks, and financial charts.
At Multisoft and PMG.net, development sat alongside technical support and network administration. At Prophet.net, I led development of financial charting and technical analysis websites, first in ASP and then in Java. I later returned to the business through Investools, working on tools used by more than 100,000 customers.
02 / Talks & community
Sharing the work.
I've shared technical work at developer conferences and in community conversations.
2021 / Fantom Developer Conference
Generative NFT Development
2022 / Consensus · Fantom session
NFT Keyed Counterfactual Smart Wallets
I also co-founded SolidityQuiz.com, a free place to test your Solidity knowledge, and previously hosted Fantom Unchained and Across the Chains.
03 / Open source
Code you can use.
Libraries, developer tools, and a few projects from the WordPress years.
Applications & developer tools
- bin-packing ↗
Cutting stock, sheet layouts, and box packing in Rust, Node.js, and WebAssembly.
- lru-cache-clustered ↗
Shared LRU caches for Node.js cluster workers.
- adaptive-cache ↗
Cache expiration that adapts to changes in content.
- Locket ↗
An encrypted local vault for development environment variables.
- nodemailer-mock ↗
Test email integrations without sending email.
- doublcov ↗
Portable LCOV reports with source browsing and coverage history.
- Validated Field for ACF ↗
Validation, input masking, and uniqueness checks for WordPress fields.
- Remote Content Shortcode ↗
Include remote content in a WordPress page or post.
Smart contract libraries & team projects
- abi-typegen ↗ · sloth-vdf ↗ · unsafe-math ↗
Typed bindings, verifiable delay proofs, and arithmetic helpers for Solidity.
- Estfor contracts ↗ · Paintswap VRF ↗
With the Paintswap team, including Sonic Airdrop definitions and the SamWitch Order Book.
04 / Elsewhere
There's a journal, too.
This site also keeps my notes on technology, travel, and photography. Some are detailed technical write-ups; others are simply things I wanted to remember.