Add a blog for the new bun runtime by julienp · Pull Request #18051 · pulumi/docs

julienp · 2026-03-19T11:58:59Z

~~Requires CLI 3.227.0 (about to be released) and @pulumi/pulumi 3.226.0 (already released)~~
Edit: everything's been released

Need to first merge:

Docs: Add Bun runtime documentation #17935
Templates: Add templates for bun templates#1075

Fixes #18052

pulumi-bot · 2026-03-19T12:08:14Z

Your site preview for commit f1a7924 is ready! 🎉

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claude · 2026-03-19T12:15:22Z

Docs Review — PR #18051

Issues

meta_image is a placeholder (blocker) — The meta.png file is literally a "100% CERTIFIED PLACEHOLDER IMAGE". The PR TODO already notes this ("TODO: Image"), but this must be replaced with a real meta image before merging. The review criteria require that meta_image is set and not the default placeholder.
Near-duplicate H2 headings — The post has both "Getting started" (line 47) and "Get started" (line 193) as H2 headings. These are confusingly similar. Consider renaming the final section to something more distinct, e.g., "Try it out" or "Start using Bun with Pulumi".
social frontmatter fields are empty (line 16–18) — The twitter and linkedin fields under social: are blank. If these aren't needed yet, consider removing the empty keys to keep the frontmatter clean, or fill them in before publishing.

Suggestions

Line 23 (opening paragraph): The sentence "This was one of our most requested features, and we're excited to ship it." — consider dropping "and we're excited to ship it" to keep the tone more matter-of-fact per blog review guidelines (avoid filler).

What looks good

 break is correctly positioned after the intro paragraph.
All code blocks have language specifiers.
Internal links verified: /docs/iac/clouds/aws/guides/lambda/, /docs/iac/concepts/providers/dynamic-providers/, /docs/iac/concepts/functions/function-serialization/, /docs/iac/languages-sdks/javascript/ all resolve.
Title is 41 characters (under 60-char limit).
Meta description is ~152 characters (under 160-char limit).
Author profile julien-poissonnier.toml exists.
H2 headings use sentence case correctly.
No "easy"/"simple" language detected.
The comparison table (runtime vs package manager) is a clear, helpful addition.
The known limitations section with the warning callout is well-structured.
Adding the bun tag to the existing bun-package-manager post is a nice touch for discoverability.

Publishing readiness checklist

 break present after intro
meta_image set and not the default placeholder — PLACEHOLDER, must be replaced
meta_image uses current Pulumi logos — cannot verify, placeholder image
Author profile exists with avatar
All links resolve
Code examples correct with language specifiers
No animated GIFs used as meta_image
Images have alt text; screenshots have 1px gray borders (no screenshots in this post)
Title ≤60 chars or allow_long_title: true set

Mention @claude in a comment if you'd like additional reviews or fixes.

claude · 2026-03-19T12:38:54Z

Docs Review — PR #18051

Scope: content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md, content/blog/bun-package-manager/index.md, content/blog/introducing-bun-as-a-runtime-for-pulumi/meta.png

Overall this is a well-structured, clearly written blog post. The conversion guide is particularly useful — breaking it into numbered steps with before/after examples makes it easy to follow. A few items to address before merging:

Issues

meta.png is a placeholder image (blocking)
The meta.png file is the default Pulumi placeholder image ("100% CERTIFIED PLACEHOLDER IMAGE"). The PR description notes "TODO: Image." This must be replaced with a real meta image before merging — placeholder images hurt social sharing and brand perception. Consider using /blog-meta-image to generate one.
Line 63 — "Prerequisites" section placement
The prerequisites (Bun 1.3+, Pulumi 3.227.0+) appear after the "Getting started" code examples. Readers should see requirements before running commands. Consider moving "Prerequisites" above the pulumi new bun step, or at minimum to right after the ## Getting started heading.
Line 196 — "Start using Bun with Pulumi" heading could be stronger
The closing section heading reads like a generic CTA. Consider something more specific like "Get started with Bun" or "Try Bun with Pulumi today" to better hook readers scanning headings.
Line 188 — Warning shortcode wrapping entire list may be too heavy
The {{% notes type="warning" %}} wraps both bullet points plus their explanations. This is a lot of content inside a warning callout. Consider using the warning only for a short summary sentence (e.g., "Callback functions and dynamic providers are not supported with the Bun runtime.") and then explaining each item as regular text below.

Suggestions

Line 22 — Opening paragraph
The opening line reads well but "with no Node.js required" could be emphasized more since it's a key selling point. Consider: "...Bun will execute your entire Pulumi program — no Node.js required."
Line 172 — Table section
The table comparing runtime: bun vs. the package-manager-only mode is helpful. Consider adding a brief recommendation sentence after it, e.g., "For new TypeScript projects, we recommend runtime: bun unless you need function serialization."
Lines 15–18 — Empty social fields
The social.twitter and social.linkedin fields are empty. If these aren't needed, consider removing the entire social block to keep the frontmatter clean.

Publishing readiness checklist

Mention @claude if you'd like additional reviews or automated fixes.

pulumi-bot · 2026-03-19T12:43:57Z

Your site preview for commit c91aad8 is ready! 🎉

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content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

pierskarsenbarg · 2026-03-20T10:39:19Z

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

+
+```typescript
+// CommonJS (Node.js default)
+const pulumi = require("@pulumi/pulumi");


In our docs, we don't do this: https://www.pulumi.com/registry/packages/aws/api-docs/account/region/#example-usage

I updated the ESM section to talk about export = ... instead, a case we actually do have in our documentation.

pierskarsenbarg · 2026-03-20T10:40:07Z

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

+
+```typescript
+// CommonJS
+module.exports = { bucketName: bucket.id };


We don't do this in our docs: https://www.pulumi.com/docs/iac/concepts/stacks/#outputs

Co-authored-by: Piers Karsenbarg <piers@pulumi.com>

pulumi-bot · 2026-03-20T10:54:06Z

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pulumi-bot · 2026-03-20T11:57:34Z

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cnunciato

Super stoked to see this and can't wait build out more content around it. 🔥

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

cnunciato · 2026-03-21T13:05:14Z

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

+- **Fast package management**: Bun's built-in package manager can install dependencies significantly faster than npm.
+- **Node.js compatibility**: Bun [aims for 100% Node.js compatibility](https://bun.sh/docs/runtime/nodejs-apis), so the npm packages you already use with Pulumi should work out of the box.
+
+With `runtime: bun`, Pulumi uses Bun for both running your program and managing your packages, giving you a streamlined single-tool experience.


Presumably also much faster startup times, native ESM support for Pulumi programs, all the goodies that come with that, etc.?

native ESM support for Pulumi programs

Pulumi supports native ESM just fine with Node.js, but we don't default to it.

I don't think the startup time matters much, so I'd rather not talk about better performance when it's unlikely to meaningfully impact the total duration of the operation.

cnunciato · 2026-03-21T13:07:58Z

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

+- **Node.js compatibility**: Bun [aims for 100% Node.js compatibility](https://bun.sh/docs/runtime/nodejs-apis), so the npm packages you already use with Pulumi should work out of the box.
+
+With `runtime: bun`, Pulumi uses Bun for both running your program and managing your packages, giving you a streamlined single-tool experience.
+


This is all good, but one thing that feels like it's somewhat missing (and could add a bit of color) is an answer to the the question, "What took you so long?" 😄 Looking back at the issue, it seems the missing piece was mainly support for http2, but as a user of both Bun and Pulumi, I'd love to hear more about how that matters and whether we hit any other issues along the way. Not a deep dive of course, just a bit more of the technical story (as it's probably pretty interesting!).

We should also update Piers's post to revise the bit about only supporting package management. I'm happy to take that on if you like — up to you!

Apparently bun started supporting GRPC on the server side in https://bun.sh/blog/bun-v1.1.31#support-for-node-http2-server-and-grpc in October 18, 2024. So I think the main reason we didn't support it as a runtime earlier was that we didn't get around to it.

content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

pulumi-bot · 2026-03-24T13:40:14Z

Your site preview for commit 9665f29 is ready! 🎉

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Co-authored-by: Christian Nunciato <c@nunciato.org>

pulumi-bot · 2026-03-30T12:20:31Z

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pulumi-bot · 2026-03-30T12:20:37Z

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julienp · 2026-04-01T06:52:53Z

I think this is ready to go, we only need to update the date for the post.

julienp temporarily deployed to testing March 19, 2026 11:59 — with GitHub Actions Inactive

julienp added the do-not-merge label Mar 19, 2026

Add a blog for the new bun runtime

c91aad8

julienp force-pushed the julienp/bun-blog branch from f1a7924 to c91aad8 Compare March 19, 2026 12:36

julienp temporarily deployed to testing March 19, 2026 12:36 — with GitHub Actions Inactive

julienp marked this pull request as ready for review March 19, 2026 12:36

pierskarsenbarg requested changes Mar 20, 2026

View reviewed changes

Update content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

db6031e

Co-authored-by: Piers Karsenbarg <piers@pulumi.com>

julienp temporarily deployed to testing March 20, 2026 10:44 — with GitHub Actions Inactive

use a better example for ESM

df250a9

julienp temporarily deployed to testing March 20, 2026 11:47 — with GitHub Actions Inactive

cnunciato self-requested a review March 21, 2026 03:26

cnunciato added needs-design Needs input from design/UX and removed needs-design Needs input from design/UX labels Mar 21, 2026

cnunciato reviewed Mar 21, 2026

View reviewed changes

Add feature and meta image

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jeffmerrick temporarily deployed to testing March 24, 2026 13:29 — with GitHub Actions Inactive

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Update content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

6523476

Co-authored-by: Christian Nunciato <c@nunciato.org>

julienp temporarily deployed to testing March 30, 2026 12:14 — with GitHub Actions Inactive

Update content/blog/introducing-bun-as-a-runtime-for-pulumi/index.md

a8bae00

Co-authored-by: Christian Nunciato <c@nunciato.org>

julienp temporarily deployed to testing March 30, 2026 12:15 — with GitHub Actions Inactive

julienp removed the do-not-merge label Mar 30, 2026

julienp removed the awaiting-upstream The issue cannot be resolved without action in another repository (may be owned by Pulumi). label Apr 1, 2026

		- Node.js compatibility: Bun [aims for 100% Node.js compatibility](https://bun.sh/docs/runtime/nodejs-apis), so the npm packages you already use with Pulumi should work out of the box.

		With `runtime: bun`, Pulumi uses Bun for both running your program and managing your packages, giving you a streamlined single-tool experience.

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claude bot commented Mar 19, 2026

Docs Review — PR #18051

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claude bot commented Mar 19, 2026

Docs Review — PR #18051

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julienp commented Mar 19, 2026 •

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