pulumi/pulumi

By the numbers

Data collected on 2026-04-30 from the master branch at commit caf13d6d14.

Size

xychart-beta horizontal
    title "Lines of code by language"
    x-axis ["Go", "Python", "TypeScript"]
    y-axis "Lines" 0 --> 220000
    bar [201568, 147029, 144577]

Language	Files	Lines
Go	4,282	201,568
Python	3,706	147,029
TypeScript	2,593	144,577
Protobuf	18	(services + messages)

Numbers are produced by find -name "*.<ext>" | wc on the working tree (excludes .git/, node_modules/, etc.). The Python and TypeScript counts are inflated by codegen test fixtures under pkg/codegen/{python,nodejs}/testdata/; raw source code in the SDK proper is smaller.

The largest source files

The engine has a handful of files that carry a disproportionate share of the codebase. New contributors regularly hit them:

File	Approx size	Role
`pkg/resource/deploy/step_generator.go`	~137 KB	Diffs old vs new and emits steps
`pkg/resource/deploy/source_eval.go`	~123 KB	Iterator that pulls events from the language host
`pkg/resource/deploy/step.go`	~88 KB	Step state machine: Same, Create, Update, Delete, Replace, ...
`sdk/go/pulumi/types_builtins.go`	~480 KB (generated)	Output types for every primitive — generated from `sdk/go/pulumi/generate/`
`sdk/go/pulumi/context.go`	~103 KB	The Go SDK's resource registration core
`sdk/go/pulumi/resource.go`	~41 KB	Resource interfaces, options, parents, dependencies
`pkg/backend/diy/backend.go`	~52 KB	DIY backend implementation
`pkg/backend/httpstate/backend.go`	~93 KB	Pulumi Cloud backend implementation
`sdk/nodejs/output.ts`	~52 KB	The Node SDK's `Output<T>`
`sdk/nodejs/resource.ts`	~68 KB	Node SDK resources
`pkg/cmd/pulumi/pulumi.go`	~33 KB	Top-level CLI command tree

Activity

Total commits: 15,092 (since 2016-10-08)
Tags / releases: 1,401
Latest tag: v3.233.0 (followed by a freeze for v2.233.0)
Commits in the last 90 days: 612
Unique authors all-time: 438

Top contributors in the last 6 months

(Excludes bot accounts. Pulled from git log --since="6 months ago".)

Contributor	Commits
Ian Wahbe	190
Thomas Gummerer	181
Julien (Bisconti)	169
Fraser Ashyggton	133
Tom Harding	46
Justin Van Patten	31
Fraser Waters	28
Tom 🐈‍⬛	27

Bot-attributed work

In the last 90 days, 134 commits (≈ 22% of merged commits) carry a Co-authored-by: trailer. Counted bots and tooling include pulumi-renovate[bot] (43 commits in 6 months) and Pulumi Bot (30 commits). This is a lower bound on AI- or automation-assisted work — inline AI tools and developer-side scripts leave no trace in the trailer.

Test ratio

Total Go files: 4,282
*_test.go files: ~1,300 (a third of Go source)
Largest test surface: pkg/engine/lifecycletest/ (deployment property/fuzz tests) and pkg/codegen/testdata/ (golden code-gen fixtures, hundreds of subdirectories per target language)

The pulumi/pulumi test suite is split into "fast" tests (no I/O, no plugins) and "all" tests (which build and link the CLI). Lifecycle fuzz tests run 10,000 Rapid checks per invocation by default — see LIFECYCLE_TEST_FUZZ_CHECKS in the Makefile.

Modules

The repo is a Go workspace of multiple modules, each with its own go.mod:

Module	Path	Purpose
`github.com/pulumi/pulumi/pkg/v3`	`pkg/`	Engine, CLI, codegen, backends
`github.com/pulumi/pulumi/sdk/v3`	`sdk/`	Core Go SDK + shared types
(tests)	`tests/`	Integration / acceptance tests
`pulumi-language-go`	`sdk/go/pulumi-language-go/`	Go language host
`pulumi-language-nodejs`	`sdk/nodejs/cmd/pulumi-language-nodejs/`	Node language host
`pulumi-language-python`	`sdk/python/cmd/pulumi-language-python/`	Python language host
`pulumi-pcl`	`sdk/pcl/`	PCL host + library

Languages of user programs supported

Language	Status	SDK in this repo?
TypeScript / JavaScript	Stable	Yes — `sdk/nodejs/`
Python	Stable	Yes — `sdk/python/`
Go	Stable	Yes — `sdk/go/pulumi/`
.NET (C# / F# / VB.NET)	Stable	No — separate repo
Java	Stable	No — separate repo
YAML	Stable	No — separate repo