SimonWillison.net is the long-running blog of Simon Willison, a software engineer, open-source creator, and co-author of the original Django framework. He writes about Python, Django, Datasette, AI tooling, prompt engineering, search, databases, APIs, data journalism, and practical software architecture. The blog includes detailed notes from experiments, conference talks, and real projects. Readers will find clear explanations of topics such as LLM workflows, SQL patterns, data publishing, scraping, deployment, caching, and modern developer tooling. Simon also publishes frequent micro-posts and TIL entries that document small discoveries and tricks from day-to-day engineering work. The tone is practical and research oriented, making the site a valuable resource for anyone interested in serious engineering and open data.
312 articles from this blog
Explains how Claude Code functions as a small game engine with a React-based scene graph pipeline for terminal UI rendering.
Anthropic publicly released Claude AI's internal 'constitution', a 35k-token document outlining its core values and training principles.
Analysis of the electricity consumption of AI coding agents like Claude Code, comparing it to household appliances based on token usage.
A university professor describes an open-book exam where students could use chatbots, analyzing the low adoption rate and student motivations.
Explores NanoLang, a new programming language designed for LLMs, and tests AI's ability to generate working code in it.
Experiments with AI coding agents scaling to build a web browser from scratch, generating over a million lines of code.
A pure C, dependency-free implementation of the FLUX.2-klein-4B AI model, created with AI assistance.
Discusses using CLI tools over REST APIs for AI agents to improve accuracy, success rates, and cost-efficiency with simpler models.
OpenAI announces ads for free ChatGPT tiers and a new 'Go' subscription, while detailing privacy safeguards and ad formats.
Introduces Open Responses, a vendor-neutral JSON API standard for hosted LLMs, based on OpenAI's Responses API and backed by major industry partners.
A deep dive into the technical design of Fly.io's Sprites, focusing on their architecture as disposable computers, warm pools, and custom persistence layer.
OpenAI researchers propose 'confessions' as a method to improve AI honesty by training models to self-report misbehavior in reinforcement learning.
Security researchers found a vulnerability in Claude Cowork allowing data exfiltration via the Anthropic API, bypassing default HTTP restrictions.
Anthropic invests $1.5 million in the Python Software Foundation to support Python ecosystem security and core development.
A prompt injection attack on Superhuman AI exposed sensitive emails, highlighting a security vulnerability in third-party integrations.
A hands-on review of Claude Cowork, Anthropic's new general AI agent for non-coding tasks, exploring its interface and capabilities.
Argues against anti-AI sentiment in software development, stating AI is a transformative and useful tool for programmers' careers.
Author explores the legal and ethical implications of using LLMs to port open source code between programming languages, based on personal experiments.
A blog post quoting Linus Torvalds on using AI-powered 'vibe-coding' to create a Python audio visualizer tool.
Explores a software library with no code, using AI agents to generate implementations from specifications and conformance tests.
