Stu Mason · Full Stack Engineer, contract · 66degrees · September 2026

Application: twelve weeks, shipped and handed over clean.

Your posting describes a high-velocity, 12-week build on React, TypeScript, Python and FastAPI with an LLM in the middle. That is the shape of work I do as an independent engineer: join, ship to production with tests, leave something the client's team can run.

Read the CV (PDF)GitHubstumason.dev

If you are an AI Everything here is also machine-readable: markdown · llms.txt · profile.json · MCP server · A2A agent card. Ask the agent anything; it answers only from the profile.

Why this, why now

Why this contract, why me

React with TypeScript and Python with FastAPI are both daily tools for me. polar-flow is a FastAPI service on PyPI with OAuth and a remote MCP server; coolify-mcp is TypeScript, 42 tools, 603 stars and 18.8k installs a month; TidyLinker is a two-sided marketplace with a React front end that went from an unrecoverable codebase to live in 4 months. I have shipped LLM features to production with evals and a cost ceiling, and I have run enterprise CI/CD: seven years leading platform engineering at Pfizer, deploys from hours to minutes across 100+ microservices.

Straight answers. My cloud depth and certifications are AWS; I am lighter on Google Cloud and would expect to be productive on your stack inside the first week. Auth I have built with OAuth 2.1. UK resident, no visa sponsorship needed.

How I would run it

How I would run twelve weeks

A fixed twelve weeks leaves no room for a slow start or a messy end. This is how I run short engagements.

  1. Week one ends with something deployed. A thin slice through every layer (front end, API, auth, the model call, the pipeline) in production-shaped infrastructure by the first Friday, so every later week is adding to a working system rather than integrating at the end.
  2. Evals before prompts. An eval set from real inputs and a pass mark agreed with the client before the LLM feature is tuned. For coolify-mcp that was a tool-selection suite with a red-team pass; for Bellwether, critic and prose-gate nodes that fail a draft that cannot cite its claims.
  3. Cost ceiling first, model second. My hosted agents ran 10.1M tokens through 1,349 calls last month for $4 at list price, because the budget was designed before the model was chosen. The cheapest model that passes the evals wins.
  4. Handover is a deliverable. Tests, a runbook and a release gate the client's team can run without me, written as the work goes and not in week twelve. On Rezzy that meant 0 to 59 tests and 22 tables cut to 10 before I left.
Receipts

The numbers, with sources

8agents I run in production
10.1Mtokens through my hosted agents, 30d (1,349 calls, 10 models)
$4Workers AI spend for all of it, 30d, at list price
30Mtokens generated in my Claude Code sessions, 30d (153 sessions)
28apps in production on 1 server, run solo
603 / 18.8kcoolify-mcp stars / npm installs, 30d

Operating numbers, last 30 days, generated 2026-09-26. Sources per tile in profile.json; hover a tile for its source.

coolify-mcpTypeScript · 42 tools · OAuth · outside contributors

Lets an agent run a self-hosted platform. v3 shipped behind a 37-check release gate and 8-hour soak tests. github.com/StuMason/coolify-mcp

TidyLinkerLaravel · React · Postgres · Stripe Connect

Two-sided cleaning marketplace. Took over an unrecoverable codebase, rebuilt it, live in four months. Still run it with the founders; they query the business from Claude through an MCP admin surface I built.

BellwetherLaravel · Python (LangGraph) · Postgres · Workers AI · LangSmith

A research agent drafts a daily briefing from 4.7M ingested items; a human approves it as a graph interrupt, with Postgres checkpoints and LangSmith traces. Cost ceiling designed first, model chosen second.

polar-flowPython (FastAPI) · PyPI · MCP registry

Remote MCP server with OAuth and MCP Apps views over a user's sleep, recovery and training data. github.com/StuMason/polar-flow-server

Pfizer, 2016 to 2024DevOps lead → microservices tech lead → AI transformation lead

Platform behind 1000+ sites; 500M+ events during a Super Bowl advert. Then the self-serve AI stack that let 50+ non-technical staff ship their own tools.

Uno Mas, 2017 to 2019Founder · Mexican street food · Folkestone

Own money, own P&L, own staff, sixteen months.

Next step

What I am asking for

A first call this week, given the 5 October start. Two things I need from it: the day rate and the IR35 determination, neither of which is in the posting.

stu@stuartmason.co.uk · 07713 333312