MT26 · Press
MT26 is a free, live forecast of all 506 races in the 3 November 2026 US midterm elections: 435 House seats, 35 Senate races and 36 governors. It was built by one developer based in France, working with Claude Code, Anthropic's AI coding tool. Its launch campaign is also run by AI agents, with a human approving every public post.
It's a model forecast with uncertainty, not a prediction of certainty. It isn't affiliated with any campaign, party or media outlet. No ads, no signup, no cookies.
Key facts
- Coverage: every House, Senate and governor race, each with its own page.
- Method: each race blends three signals (partisan lean, expert ratings and public polls), then the whole election is simulated 20,000 times with errors shared across similar races, so a polling miss in one state shows up in its neighbours.
- Updates: the forecast reruns several times a day until Election Day morning.
- Election night: it switches to the official count from state and county election offices only. It projects the votes still to be counted by type (early, mail, Election Day), each from its own counted margin. A race is marked "projected by this model" only at 99.9% with 60% of the expected vote counted, or 99% with 95%. Race calls are credited to AP.
- Open about its limits: the methodology page publishes the full method, CSV downloads and a calibration check against Cook Political Report ratings from 1984 to 2022. It says plainly that the model hasn't been back-tested on past midterms.
How it was built
- Who did what: the developer set the goals and made every decision; Claude Code wrote the model, the data pipeline, the interactive "Lab" views and the pages.
- Stack: a Cloudflare Worker serves the site; the front end is plain JavaScript; the Lab uses WebGL. Visit counting is aggregate only, with no cookies and no IP storage; outside the EU, Cloudflare's cookieless Web Analytics also counts page views.
- The campaign: an AI agent acting as head of marketing drafts posts, measures visits by channel and requests site changes. A human approves every public post and every deploy.
Images
Free to use with credit "MT26 (midtermsforecast.com)":
Home on a phone: House and Senate chances · PNG, 1170×2532
A race page: chances, photos and the projected-margin chart · PNG, 1170×2532
Senate forecast map · PNG, 2880×1800
The Lab: "What if the polls are wrong?", both chambers by size of polling miss · PNG, 2880×1800
Contact
Methodology: midtermsforecast.com/methodology · How it was built: midtermsforecast.com/how-built