Simon Willison’s Weblog

The fate of “small” open source. Nolan Lawson asks if LLM assistance means that the category of tiny open source libraries like his own blob-util is destined to fade away.

Why take on additional supply chain risks adding another dependency when an LLM can likely kick out the subset of functionality needed by your own code to-order?

I still believe in open source, and I’m still doing it (in fits and starts). But one thing has become clear to me: the era of small, low-value libraries like blob-util is over. They were already on their way out thanks to Node.js and the browser taking on more and more of their functionality (see node:glob, structuredClone, etc.), but LLMs are the final nail in the coffin.

I've been thinking about a similar issue myself recently as well.

Quite a few of my own open source projects exist to solve problems that are frustratingly hard to figure out. s3-credentials is a great example of this: it solves the problem of creating read-only or read-write credentials for an S3 bucket - something that I've always found infuriatingly difficult since you need to know to craft an IAM policy that looks something like this:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:ListBucket",
        "s3:GetBucketLocation"
      ],
      "Resource": [
        "arn:aws:s3:::my-s3-bucket"
      ]
    },
    {
      "Effect": "Allow",
      "Action": [
        "s3:GetObject",
        "s3:GetObjectAcl",
        "s3:GetObjectLegalHold",
        "s3:GetObjectRetention",
        "s3:GetObjectTagging"
      ],
      "Resource": [
        "arn:aws:s3:::my-s3-bucket/*"
      ]
    }
  ]
}

Modern LLMs are very good at S3 IAM polices, to the point that if I needed to solve this problem today I doubt I would find it frustrating enough to justify finding or creating a reusable library to help.

# 17th November 2025, 11:24 pm / open-source, ai, generative-ai, llms, ai-assisted-programming, nolan-lawson

Retiring Pinafore (via) Nolan Lawson built Pinafore, which became my default Mastodon client on both desktop and mobile over the past month. He thoughtfully explains why he’s ending his involvement in the project—and why, for trust reasons, he’s not planning on handing over the reigns to someone else. Pinafore is everything I want a good SPA to be—it loads fast, works offline and packs a whole lot of functionality into a tiny package. I’m sad to see Nolan’s involvement come to end—it’s a superb piece of software.

# 10th January 2023, 2:05 am / javascript, mastodon, nolan-lawson

The balance has shifted away from SPAs (via) “There’s a feeling in the air. A zeitgeist. SPAs are no longer the cool kids they once were 10 years ago.” Nolan Lawson offers some opinions on why the pendulum seems to be swinging back in favour of server-side rendering over rendering every page entirely on the client. He argues that paint holding, back-forward caching and service workers have made the benefits of SPAs over MPAs much less apparent. I’m inclined to agree.

# 22nd May 2022, 2:47 am / javascript, frontend, nolan-lawson

A tour of JavaScript timers on the web (via) By Nolan Lawson. Do you understand the differences between setTimeout, setInterval, setImmediate, requestAnimationFrame and requestIdleCallback? I didn't.

# 2nd September 2018, 10:10 am / javascript, nolan-lawson