Carter Appleton

Work

1. '26
   Neynar '26

   Staff Engineer

   Scaled onchain wallet infrastructure for the Farcaster social network. Evolved Clanker, the onchain token launcher I helped build, for emerging US legal frameworks.

   stayed through two acquisitions
2. '25 – '26
   Farcaster '25 – '26

   Staff Engineer · Acquired by Neynar

   Designed a new onchain presale mechanism for community funding.
3. '25 – '26
   Clanker '25 – '26

   Founding Engineer · Acquired by Farcaster, then Neynar

   Shipped a production LLM agent with tool use and a custom multi-model router handling tens of thousands of queries a day, plus an early AI-native SDK for developers and LLMs alike, now at 250k downloads. Owned backend, frontend, SDK, and data pipeline at a 4-person startup: millions of hits/day, nearly $20B in volume at $10M+ ARR. Four portfolio projects raised venture funding in the first year.

   more detail

   • Designed and shipped LLM agent with tool-use and a custom multi-model router handling tens of thousands of user queries daily
   • Designed SDK for developers and LLMs, focusing on ease of use; an early AI-native API with 250k downloads
   • Owned backend, frontend, SDK, and data pipeline at our 4-person startup; nearly $20B in volume at $10M+ ARR
   • System deployed tens of thousands of tokens daily, serving millions of hits/day
   • Built Rust library for fast and efficient deterministic onchain address generation
   • Ran weekly developer office hours and integrated direct feedback into the product
   • Mentored team members on system design and shipping under acquisition pressure; authored the internal doc that drove our acquisition
   • Four portfolio companies launched via Clanker raised venture funding in the first year
4. '22 – '25
   Warbler Labs '22 – '25

   Staff Engineer

   Tech lead on a team of 5 at the lab behind Goldfinch and Heron Finance. Built a pipeline that ingests hundreds of companies' complex financial reports and normalizes them losslessly, a portfolio optimizer over 10k assets, a $30M automated asset management system, and the first production passkey wallets. Mentored three engineers to promotion.

   more detail

   • Tech lead on a team of 5; drove technical architecture for backend and smart contracts
   • Built a pipeline extracting and losslessly normalizing unstructured financial reports from hundreds of companies
   • Built linear programming rebalancing engine optimizing portfolios across thousands of performing assets
   • Led engineering of a $30M smart contract system in Solidity, generating 10%+ yield
   • Built the first production use of account-abstracted crypto wallets, holding over $30M
   • Lab behind Goldfinch (onchain real-world asset platform) and Heron Finance (private market investment platform)
   • Mentored three engineers to promotion (one to Senior, two to Staff)
5. '16 – '21
   Airbnb '16 – '21

   Engineer → Senior → Staff

   Architected the customer-service chatbot and led the 10-person cross-functional team that built it, whose NLP resolutions cut overall CX contacts by ~3%. Two months after launch, COVID hit and every US reservation got canceled at once, and I finally got to test the 10× load every engineer is supposed to plan for. It held. I also ran the release manager rotation and gave internal talks on deploy observability, watching metrics move as your code ships. Co-invented a patented NLP sentiment system along the way.

   more detail

   • Architected and led cross-functional team of 10 building the customer service chatbot, whose NLP resolutions cut overall CX contacts by ~3%
   • Chatbot launched two months before COVID and handled 100x surge when all US reservations were canceled
   • Served on the release manager rotation gating releases and verifying builds; ran talks on deploy observability, watching metrics move as your code ships
   • Built multilingual contact flow and CMS knowledge base for customer support
   • Co-invented NLP sentiment analysis system (US Patent)
   • Built taxonomy system to optimize CX agent workflows
   • Mentored junior engineers across multiple teams
   • Started and ran the Seattle office internship program
6. '11 – '17
   Cat Facts '11 – '17

   Founder · Sold

   The internet-famous texting service that ranked #1 on Google for "cat facts." Tens of thousands of subscribers, millions of impressions/year, 30% viral rate. Wrote a word-weight classifier for auto-responses years before LLMs existed.

   more detail

   • The internet-famous Cat Facts texting service, ranked #1 on Google for "cat facts"
   • Tens of thousands of customers and millions of impressions annually; 30% viral rate
   • Ran marketing campaigns across Facebook, Reddit, and Twitter, analyzing post effectiveness
   • Automated customer interactions with a custom NLP system years before LLMs existed
7. '15 – '16
   Microsoft '15 – '16

   Software Engineer
8. '11 – '15
   Carnegie Mellon '11 – '15

   BS, Computer Science
9. '09 – '13
   iOS Developer '09 – '13

   Founder

   Four puzzle games. The hit one got 30k downloads, almost all in China, with fan mail in Mandarin asking for more levels.

   more detail

   • Puzzle games with 100k+ downloads
   • Top app got 30k downloads, primarily in China
10. summer '14
    Microsoft summer '14

    Intern
11. summer '13
    Microsoft summer '13

    Intern
12. summer '12
    Motion Math summer '12

    Intern

What I've shipped

Recent writing

• Aug 2026 Gear Review: Lowa Renegade hiking
• Jul 2026 Gear Review: Norda 001 running
• Jun 2026 Gear Review: Salomon S/LAB Shift Binding skiing
• Jun 2026 Self-Guided Backcountry Skiing in Hokkaido skiing

Guilty pleasures

Thanks for stopping by. I'm always up for a good conversation, say hello or read something I wrote.