Simon Willison is a British programmer whose public record runs in two long arcs: he helped invent one of the web's dominant frameworks, and then — through a self-run publishing apparatus — became the working practitioner's reference for large language models.
Formation and Django
Born in January 1981 in the United Kingdom, Willison studied computer science at the University of Bath and began blogging in 2002, in his first year — a habit that now defines his public identity. In 2003 he took a "year in industry" placement at the Lawrence Journal-World newspaper in Lawrence, Kansas, working alongside Adrian Holovaty. Frustrated with their existing tools, the pair built an abstraction layer over their newsroom sites that they long called simply "the CMS"; released as open source in July 2005, it became the Django web framework. Willison announced it on his blog on 17 July 2005, crediting Holovaty as co-creator and noting Jacob Kaplan-Moss and designer Wilson Miner on the early team.
Journalism, startups, and independence
After graduating in 2005 he worked at Yahoo on the Technology Development team and the early Fire Eagle geolocation service, then consulted on OpenID. In October 2008 he joined Guardian News & Media in London as a software architect. His signature project there arrived in June 2009: "Investigate your MP's expenses", a crowdsourcing application built in about a week that enlisted more than 20,000 volunteers to review 170,000 documents in its first 80 hours — an early landmark of data journalism and the Guardian's first live Django-powered app.
In 2010 he co-founded Lanyrd, a social conference directory, with Natalie Downe, building it while the couple travelled on their honeymoon. Lanyrd went through Y Combinator's Winter 2011 batch, raised roughly $1.4 million in seed funding, and was acquired by Eventbrite on 3 September 2013 — one of that company's first acquisitions. Willison relocated to San Francisco and worked at Eventbrite until July 2019, self-listed as Director of Architecture.
Since then he has been an independent open source developer. A 2019 JSK Journalism Fellowship at Stanford funded a year of work on tools for data journalism — the direct ancestor of his current occupation, which he describes as building open source tools around Datasette and SQLite.
The Datasette ecosystem
Datasette, first released 13 November 2017, turns SQLite databases into browsable web interfaces and JSON APIs. Around it grew a methodical toolbelt: sqlite-utils (2019) for building databases, Dogsheep for repatriating personal data into a private warehouse, "git scraping" (named October 2020) for snapshotting third-party data into Git history, shot-scraper (2022) for automated screenshots and scraping, and llm (April 2023), a command-line tool with a plugin system for API-hosted and self-hosted models. In April 2025 he and Alex Garcia launched Datasette for Newsrooms on the hosted Datasette Cloud service. When the CIA discontinued the World Factbook in February 2026, he recovered the last downloadable edition into a public repository within a day — a characteristic gesture.
The LLM era
On 12 September 2022, responding to Riley Goodside's demonstrations of tricking GPT-3 with malicious input, Willison proposed the name "prompt injection" — now the standard term for a class of attacks he still says has no reliable fix. He extended that adversarial framing in June 2025 with "the lethal trifecta": agents that combine private-data access, untrusted content, and external communication are exploitable, and the only dependable defense is removing a leg, not adding guardrails. His PyCon US 2024 keynote argued for "imitation intelligence" over "artificial intelligence"; his May 2024 post championed "slop" for unwanted AI-generated content; and in February 2026 he began the Agentic Engineering Patterns guide for professional work with coding agents. Press and podcasts routinely describe him as one of the most influential independent voices on applied AI — influence he attributes to nothing more exotic than blogging consistently.
The practice underneath
The throughline is writing as engineering practice: the "perfect commit" bundling code, tests, and documentation; TILs that drop the publishing bar to "did I just learn something?"; weeknotes; annotated talk transcripts; and a policy of never publishing AI-generated prose under his own name. The blog, TIL repo, and project docs are not commentary on the work — they are the work's durability mechanism.
What the record does not settle
Attribution has seams: The Economist has described "prompt injection" as independently coined by Willison and others. Reference coverage is thin — his Wikipedia article was nominated for deletion in 2026 — and no canonical project count exists. This index preserves those seams rather than smoothing them.
This index was compiled from public sources and does not imply the subject's endorsement. Citations live in the packet's source catalog.