diff --git a/.changeset/big-countries-pump.md b/.changeset/big-countries-pump.md
new file mode 100644
index 000000000000..3a9fb9a9086b
--- /dev/null
+++ b/.changeset/big-countries-pump.md
@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+Add public API to let adapters update .gitignore
diff --git a/documentation/docs/10-adapters.md b/documentation/docs/10-adapters.md
index fcfb8bbdef15..1514ea3c5d34 100644
--- a/documentation/docs/10-adapters.md
+++ b/documentation/docs/10-adapters.md
@@ -31,6 +31,15 @@ export default {
 };
 ```
 
+Some adapters may modify your project's `.gitignore` to include their build output. In case you don't want those patterns included you can comment them out: 
+
+```diff
+.svelte-kit
+.env
+
+- build
++ # build
+```
 A variety of official adapters exist for serverless platforms...
 
 - [`adapter-cloudflare-workers`](https://github.com/sveltejs/kit/tree/master/packages/adapter-cloudflare-workers) — for [Cloudflare Workers](https://developers.cloudflare.com/workers/)
diff --git a/documentation/docs/80-adapter-api.md b/documentation/docs/80-adapter-api.md
index 0f14a4d275b3..1b67b66e6ec1 100644
--- a/documentation/docs/80-adapter-api.md
+++ b/documentation/docs/80-adapter-api.md
@@ -26,6 +26,7 @@ The types for `Adapter` and its parameters are available in [types/config.d.ts](
 Within the `adapt` method, there are a number of things that an adapter should do:
 
 - Clear out the build directory
+- Call `utils.update_ignores` to ignore build output in existing `.gitignore` files at the location of `svelte.config.js`
 - Output code that:
   - Calls `init`
   - Converts from the patform's request to a [SvelteKit request](#hooks-handle), calls `render`, and converts from a [SvelteKit response](#hooks-handle) to the platform's
diff --git a/packages/adapter-cloudflare-workers/index.js b/packages/adapter-cloudflare-workers/index.js
index 856d162d3f27..ac52cf03fcc3 100644
--- a/packages/adapter-cloudflare-workers/index.js
+++ b/packages/adapter-cloudflare-workers/index.js
@@ -16,6 +16,8 @@ export default function () {
 
 			const files = fileURLToPath(new URL('./files', import.meta.url));
 
+			utils.update_ignores({ patterns: [bucket, entrypoint] });
+
 			utils.rimraf(bucket);
 			utils.rimraf(entrypoint);
 
diff --git a/packages/adapter-netlify/index.js b/packages/adapter-netlify/index.js
index fe2f48a6f64c..218cb4214c45 100644
--- a/packages/adapter-netlify/index.js
+++ b/packages/adapter-netlify/index.js
@@ -17,6 +17,8 @@ export default function () {
 
 			const files = fileURLToPath(new URL('./files', import.meta.url));
 
+			utils.update_ignores({ patterns: [publish, functions] });
+
 			utils.log.minor('Generating serverless function...');
 			utils.copy(join(files, 'entry.js'), '.svelte-kit/netlify/entry.js');
 
diff --git a/packages/adapter-node/index.js b/packages/adapter-node/index.js
index 5640e6804986..631af7880d98 100644
--- a/packages/adapter-node/index.js
+++ b/packages/adapter-node/index.js
@@ -36,6 +36,7 @@ export default function ({
 		name: '@sveltejs/adapter-node',
 
 		async adapt({ utils, config }) {
+			utils.update_ignores({ patterns: [out] });
 			utils.log.minor('Copying assets');
 			const static_directory = join(out, 'assets');
 			utils.copy_client_files(static_directory);
diff --git a/packages/adapter-static/index.js b/packages/adapter-static/index.js
index 5155fec1b8a6..d684cba3dd48 100644
--- a/packages/adapter-static/index.js
+++ b/packages/adapter-static/index.js
@@ -11,6 +11,7 @@ export default function ({ pages = 'build', assets = pages, fallback } = {}) {
 		name: '@sveltejs/adapter-static',
 
 		async adapt({ utils }) {
+			utils.update_ignores({ patterns: [pages, assets] });
 			utils.copy_static_files(assets);
 			utils.copy_client_files(assets);
 
diff --git a/packages/adapter-static/test/apps/prerendered/.gitignore b/packages/adapter-static/test/apps/prerendered/.gitignore
index 0a4623184983..06f3fb94e666 100644
--- a/packages/adapter-static/test/apps/prerendered/.gitignore
+++ b/packages/adapter-static/test/apps/prerendered/.gitignore
@@ -3,3 +3,5 @@ node_modules
 /.svelte-kit
 /build
 /functions
+
+build
diff --git a/packages/adapter-static/test/apps/spa/.gitignore b/packages/adapter-static/test/apps/spa/.gitignore
index 0a4623184983..06f3fb94e666 100644
--- a/packages/adapter-static/test/apps/spa/.gitignore
+++ b/packages/adapter-static/test/apps/spa/.gitignore
@@ -3,3 +3,5 @@ node_modules
 /.svelte-kit
 /build
 /functions
+
+build
diff --git a/packages/adapter-vercel/index.js b/packages/adapter-vercel/index.js
index aef613d2f895..7beac2f6ca46 100644
--- a/packages/adapter-vercel/index.js
+++ b/packages/adapter-vercel/index.js
@@ -10,6 +10,8 @@ export default function () {
 
 		async adapt({ utils }) {
 			const dir = '.vercel_build_output';
+
+			utils.update_ignores({ patterns: [dir] });
 			utils.rimraf(dir);
 
 			const files = fileURLToPath(new URL('./files', import.meta.url));
diff --git a/packages/create-svelte/shared/+eslint+prettier/package.json b/packages/create-svelte/shared/+eslint+prettier/package.json
index ac3aca10acf1..8cb0595e99da 100644
--- a/packages/create-svelte/shared/+eslint+prettier/package.json
+++ b/packages/create-svelte/shared/+eslint+prettier/package.json
@@ -3,7 +3,7 @@
 		"eslint-config-prettier": "^8.1.0"
 	},
 	"scripts": {
-		"lint": "prettier --check --plugin-search-dir=. . && eslint --ignore-path .gitignore .",
-		"format": "prettier --write --plugin-search-dir=. ."
+		"lint": "prettier --ignore-path .gitignore  --check --plugin-search-dir=. . && eslint --ignore-path .gitignore .",
+		"format": "prettier --ignore-path .gitignore --write --plugin-search-dir=. ."
 	}
 }
diff --git a/packages/create-svelte/shared/+prettier/.prettierignore b/packages/create-svelte/shared/+prettier/.prettierignore
deleted file mode 100644
index d26fa1cff1b9..000000000000
--- a/packages/create-svelte/shared/+prettier/.prettierignore
+++ /dev/null
@@ -1,4 +0,0 @@
-.svelte-kit/**
-static/**
-build/**
-node_modules/**
diff --git a/packages/create-svelte/shared/-eslint+prettier/package.json b/packages/create-svelte/shared/-eslint+prettier/package.json
index e9103a7e238c..af5326c65c5a 100644
--- a/packages/create-svelte/shared/-eslint+prettier/package.json
+++ b/packages/create-svelte/shared/-eslint+prettier/package.json
@@ -1,6 +1,6 @@
 {
 	"scripts": {
-		"lint": "prettier --check --plugin-search-dir=. .",
-		"format": "prettier --write --plugin-search-dir=. ."
+		"lint": "prettier --ignore-path .gitignore --check --plugin-search-dir=. .",
+		"format": "prettier --ignore-path .gitignore --write --plugin-search-dir=. ."
 	}
 }
diff --git a/packages/kit/src/core/adapt/utils.js b/packages/kit/src/core/adapt/utils.js
index 21ee6822b0f4..a26c8164cc69 100644
--- a/packages/kit/src/core/adapt/utils.js
+++ b/packages/kit/src/core/adapt/utils.js
@@ -1,6 +1,7 @@
 import { SVELTE_KIT } from '../constants.js';
 import { copy, rimraf, mkdirp } from '../filesystem/index.js';
 import { prerender } from './prerender.js';
+import fs from 'fs';
 
 /**
  *
@@ -47,6 +48,25 @@ export function get_utils({ cwd, config, build_data, log }) {
 					log
 				});
 			}
+		},
+
+		/** @param {{patterns: string[], log?: boolean}} options */
+		update_ignores({ patterns, log = true }) {
+			const target = '.gitignore';
+			if (!fs.existsSync(target)) return;
+
+			const file = fs.readFileSync(target, { encoding: 'utf-8' });
+			const eol = file.includes('\r\n') ? '\r\n' : '\n';
+			const lines = file.split(eol);
+			const new_lines = new Set(patterns);
+			// remove repeated lines
+			for (const line of lines) {
+				// this will prevent commented ignores to be reinserted
+				new_lines.delete(line.replace(/#\s*/, ''));
+			}
+			if (new_lines.size === 0) return;
+			fs.writeFileSync(target, [...lines, ...new_lines].join(eol));
+			if (log) this.log.success(`Updated ${target}`);
 		}
 	};
 }
diff --git a/packages/kit/types/config.d.ts b/packages/kit/types/config.d.ts
index 45482dddb12f..5903e4c9cc0c 100644
--- a/packages/kit/types/config.d.ts
+++ b/packages/kit/types/config.d.ts
@@ -9,6 +9,7 @@ export type AdapterUtils = {
 	copy_server_files: (dest: string) => void;
 	copy_static_files: (dest: string) => void;
 	copy: (from: string, to: string, filter?: (basename: string) => boolean) => void;
+	update_ignores: ({ patterns, log }: { patterns: string[]; log?: boolean }) => void;
 	prerender: ({
 		all,
 		dest,