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SLSean Langshaw

Founder and developer/Miami–Fort Lauderdale/Global

Sean Langshaw

I build the software that holds the money, the model, and the record.

Founder and architect of DeFi AI Technologies. The primary build is Sovereign Core OS: operator-controlled treasury, tenant-issued stablecoins, and private AI inside one system. Alongside it, KTE keeps a tipped worker’s shift ledger, and EcoSip runs a reusable coffee cup as software a brand can license.

01 — Work

Three companies. One builder.

DeFi AI is the primary project. KTE and EcoSip are the other companies in market. Each card leaves this site and opens the business.

01 · Primary · design-partner phase

Founder and architect

DeFi AI Technologies

Sovereign Core OS

An air-gapped financial operating system, already running across 24 internal business units. External institutions enter through design-partner pilots and land on the same system.

Institutions are being asked to drop a model into the workflows that move money, then trust a vendor with the prompts, the positions, and the keys. Sovereign Core refuses that trade. Treasury, wallets, escrow, and the trading desk stay with the operator. gUSD and its regional pegs are tenant-issued: the institution signs the mint, rather than renting a stablecoin issuer. Private inference and agent orchestration run inside the same perimeter. When a session has to leave the chat, that context is drafted into a PDF for formal review. Consulting is the onboarding path. The product is the operating system.

What the system is

  1. 01 IntelligencePrivate inference · MCP · agent runbooks
  2. 02 OperationsTreasury · escrow · wallets · trading
  3. 03 SettlementTenant-issued gUSD · regional pegs · rails
  4. Under the operator’s keys. No vendor telemetry.
  • Air-gapped and self-hosted deployment
  • Sovereign-cloud and hybrid custody options
  • Wallets, treasury, escrow, and a trading desk
  • Tenant-issued gUSD and regional pegs
  • Private inference and MCP orchestration
  • Chat context drafted to PDF for formal review
  • TypeScript platform, Next.js public site, EVM settlement

02 · In market

KTE

Keeping Table Etiquette

A worker-owned notebook for tipped hospitality. Hours, tips, and tip-outs, written down by the person who worked the shift.

Tipped work runs on a number the worker rarely controls. The record usually lives in a manager’s drawer or a point-of-sale system they cannot export. KTE keeps a dated ledger, an effective hourly rate, and a file they can hand to a preparer, a manager, or counsel. A chat can draft that same context into a PDF when the conversation has to be reviewed as a document. Operators see location-level risk only in aggregate, so a compliance view never becomes surveillance of a named person. An attorney directory sits beside the record, with no paid placement. I built it because a sovereign treasury and a Friday closeout ask the same question: who holds the number, and can they prove it later.

  • Next.js and Expo
  • PostgreSQL and Prisma
  • Self-hosted authentication
  • In-app Stripe checkout
  • k-anonymous operator dashboards
  • Chat context drafted to PDF for formal review
kte.finance (opens in a new tab)

03 · In market

EcoSip

Reusable cup network

Software for a cup that comes back: registration, refills, rewards, and a console a coffee brand can run.

A single-use cup is a waste problem and a brand problem. EcoSip is the operating loop around the other kind of cup. A person registers it, refills it on a program, and can see the waste they avoided. A coffee company runs inventory, deposits, and the environmental record from its own console. The public site, the consumer app, and the business app are separate surfaces in one monorepo, with co-brand theming so a shop can look like itself inside a shared network. I built it to turn a sustainability claim into software a brand can license.

  • Next.js monorepo on pnpm and Turborepo
  • PostgreSQL and Prisma
  • Self-hosted authentication
  • Consumer, business, and marketing apps
  • Co-brand theming for coffee operators
ecosip.io (opens in a new tab)

02 — Bench

Private work, left unfinished.

These are original repositories, not the public forks on GitHub. They are not companies in market, and their old preview deploys no longer serve. REIT DAO and the property network became the Global Property Network inside DeFi AI. Chat with PDF became the step, in DeFi AI and KTE, that drafts a chat into a PDF for formal review.

  1. 012023

    REIT DAO

    Private · unfinished

    Tokenized real estate. Solidity contracts and a dapp for claim, mint, and stake. The founder work that pointed at real-world assets. The property thread continues inside DeFi AI as the Global Property Network. The original repositories are still private.

  2. 022024–2025

    Global Property Network

    Private · unfinished

    A property-network application started as its own product. The live direction is the GPN surface inside Sovereign Core, not this standalone repo.

  3. 032024

    Chat with PDF

    Continued in DeFi AI and KTE

    Started as an AI workspace for uploading documents and talking to them. Unfinished as its own product. The part that held up moved into DeFi AI and KTE: the chat is the working context, and the system drafts that context into a PDF when the record has to be reviewed formally.

  4. 042024

    Co-host

    Private · unfinished

    Operations software for people co-hosting on Airbnb and other marketplaces.

  5. 052024

    Auto-auction study

    Private · unfinished

    A study of bid manipulation in online auto auctions. Research software, not a company.

03 — Practice

Where the work sits.

AI-driven software, treasury operations, and blockchain settlement. The through-line is operator control: the institution, the brand, or the worker keeps the record.

  • 01

    Treasury operations

    Wallets, sweeps, escrow, and the desk an institution actually runs. The product starts at the money, not at a chatbot wrapped around a spreadsheet.

  • 02

    Stablecoin settlement

    Tenant-issued gUSD and regional pegs, same-currency, under the operator’s signature. The issuer is the institution. A third party does not hold the mint.

  • 03

    Agentic systems

    Inference, tool use, and MCP orchestration that stay on hardware the operator controls. Prompts and positions do not phone home.

  • 04

    Product engineering

    TypeScript, Next.js, PostgreSQL, Prisma, self-hosted auth, Stripe, and Expo. One person can hold the public site, the API, the ledger, and the phone app.

  • 05

    Honest system status

    Live desks and environment-gated rails are labeled as what they are. A design-partner pilot is not described as a general launch.

  • 06

    Founder range

    The company, the pricing, the data model, and the interface sit in the same hands. Navy air traffic control before that: procedure, real time, and a record that has to be right.

04 — Record

How this developer was made.

Formal credentials started in the Navy and extended from 2001 to 2003 with a Master of Arts in Computer Resources and Information Management from Webster University. I left the Navy in December 2002, joined CSX Transportation in January 2003 as a dispatcher, and was chief train dispatcher from 2006 until 2018. Starting in 2006 I built an operations system for crew, dispatch, power, train, reporting, and documentation, and CSX adopted it in 2010–2012. I started eMCycles in 2014 and left the railroad in 2018 to build it. COVID in 2020 turned me toward the software companies on this page. eMCycles is on hold until a prototype can be paid for from KTE or EcoSip, which I own outright. Updated formal credentials run from January through July 2024: front end, generative AI, AWS, then enterprise architecture. The developer on this page was built by shipping the companies above, on top of a Navy career that was already about high-stakes procedure.

  1. United States Navy

    Air traffic controller

    Former Navy AC. I left the Navy in December 2002. The work was real-time judgment, a shared picture, and a record that other people act on. That habit is still the engineering standard: say what is live, say what is waiting, and do not invent a fill.

  2. 2001–2003

    Master of Arts

    Webster University, School of Business and Technology, Saint Louis. Master of Arts in Computer Resources and Information Management, conferred 17 May 2003.

  3. January 2003–2018

    CSX Transportation

    Joined CSX Transportation in January 2003 as a dispatcher, and was chief train dispatcher from 2006 until 2018.

  4. 2006–2012

    Operations system

    Personal projects, and an operations system for crew, dispatch, power, train, reporting, and documentation, started in 2006. CSX adopted it in 2010–2012.

  5. 2014 → now

    eMCycles

    I started eMCycles in 2014 and left the railroad in 2018 to build it. COVID in 2020 turned me toward the software companies on this page. eMCycles is on hold until a prototype can be paid for from KTE or EcoSip, which I own outright.

  6. January–February 2024

    Meta Front-End Developer

    Meta’s Front-End Developer Specialization, issued February 2024. The track under it: introduction to front-end development, HTML and CSS in depth, JavaScript, version control, React basics, advanced React, principles of UX/UI design, and the front-end capstone.

  7. February 2024

    IBM generative AI

    Two IBM specializations: Generative AI Fundamentals, and Generative AI for Software Developers. Under them: introduction and applications, prompt engineering, foundation models and platforms, and impact, considerations, and ethics. That is the formal layer under the agent work in DeFi AI and KTE.

  8. June 2024

    AWS cloud

    Amazon Web Services, from practitioner foundations through architecture. Cloud Practitioner Essentials, Cloud Technical Essentials, the Certified Cloud Practitioner exam prep, Architecting Solutions on AWS, and Introduction to Designing Data Lakes on AWS. Closed with two specializations: AWS Cloud Solutions Architect, and AWS Cloud Technology Consultant.

  9. July 2024

    TOGAF 10 Foundation

    Issued by EDUCBA. Enterprise architecture, on top of the cloud and software credentials: how a system is structured before it is coded.

  10. 2023 → now

    Companies, in order of the work

    REIT DAO, tokenizing real estate. eMCycles, an electric motorcycle company, including a manufacturing-facility proposal for Miramar, on hold until a prototype can be paid for from KTE or EcoSip, which I own outright. Then the three builds on this page: EcoSip, KTE, and DeFi AI Technologies, where the current architecture work lives.

05 — Contact

sdl@sdlangshaw.com

For a Sovereign Core briefing, start at defiai.finance. Those conversations are under NDA. This page is the person who builds the system.