diff --git a/fixtures/cjs-config-file-cjs/.size-limit.cjs b/fixtures/cjs-config-file-cjs/.size-limit.cjs
new file mode 100644
index 00000000..a086cba0
--- /dev/null
+++ b/fixtures/cjs-config-file-cjs/.size-limit.cjs
@@ -0,0 +1,5 @@
+module.exports = [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/cjs-config-file-cjs/index.js b/fixtures/cjs-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/cjs-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/cjs-config-file-cjs/package.json b/fixtures/cjs-config-file-cjs/package.json
new file mode 100644
index 00000000..1f2bada2
--- /dev/null
+++ b/fixtures/cjs-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "cjs-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/cjs-config-file-esm/.size-limit.cjs b/fixtures/cjs-config-file-esm/.size-limit.cjs
new file mode 100644
index 00000000..31503c8c
--- /dev/null
+++ b/fixtures/cjs-config-file-esm/.size-limit.cjs
@@ -0,0 +1,5 @@
+export default [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/cjs-config-file-esm/index.js b/fixtures/cjs-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/cjs-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/cjs-config-file-esm/package.json b/fixtures/cjs-config-file-esm/package.json
new file mode 100644
index 00000000..71520bbb
--- /dev/null
+++ b/fixtures/cjs-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "cjs-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/cts-config-file-cjs/.size-limit.cts b/fixtures/cts-config-file-cjs/.size-limit.cts
new file mode 100644
index 00000000..a759eaa9
--- /dev/null
+++ b/fixtures/cts-config-file-cjs/.size-limit.cts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+module.exports = [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/cts-config-file-cjs/index.js b/fixtures/cts-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/cts-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/cts-config-file-cjs/package.json b/fixtures/cts-config-file-cjs/package.json
new file mode 100644
index 00000000..59971b5d
--- /dev/null
+++ b/fixtures/cts-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "cts-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/cts-config-file-esm/.size-limit.cts b/fixtures/cts-config-file-esm/.size-limit.cts
new file mode 100644
index 00000000..99ffbf69
--- /dev/null
+++ b/fixtures/cts-config-file-esm/.size-limit.cts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+export default [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/cts-config-file-esm/index.js b/fixtures/cts-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/cts-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/cts-config-file-esm/package.json b/fixtures/cts-config-file-esm/package.json
new file mode 100644
index 00000000..c39c32d8
--- /dev/null
+++ b/fixtures/cts-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "cts-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/cts-config-file/.size-limit.cts b/fixtures/cts-config-file/.size-limit.cts
new file mode 100644
index 00000000..a759eaa9
--- /dev/null
+++ b/fixtures/cts-config-file/.size-limit.cts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+module.exports = [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/cts-config-file/index.js b/fixtures/cts-config-file/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/cts-config-file/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/cts-config-file/package.json b/fixtures/cts-config-file/package.json
new file mode 100644
index 00000000..0189ba5c
--- /dev/null
+++ b/fixtures/cts-config-file/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "cts-config-file",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/js-config-file-cjs/.size-limit.js b/fixtures/js-config-file-cjs/.size-limit.js
new file mode 100644
index 00000000..a086cba0
--- /dev/null
+++ b/fixtures/js-config-file-cjs/.size-limit.js
@@ -0,0 +1,5 @@
+module.exports = [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/js-config-file-cjs/index.js b/fixtures/js-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/js-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/js-config-file-cjs/package.json b/fixtures/js-config-file-cjs/package.json
new file mode 100644
index 00000000..be46cbd1
--- /dev/null
+++ b/fixtures/js-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "js-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/js-config-file-esm/.size-limit.js b/fixtures/js-config-file-esm/.size-limit.js
new file mode 100644
index 00000000..31503c8c
--- /dev/null
+++ b/fixtures/js-config-file-esm/.size-limit.js
@@ -0,0 +1,5 @@
+export default [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/js-config-file-esm/index.js b/fixtures/js-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/js-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/js-config-file-esm/package.json b/fixtures/js-config-file-esm/package.json
new file mode 100644
index 00000000..6825c6d1
--- /dev/null
+++ b/fixtures/js-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "js-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/mjs-config-file-cjs/.size-limit.mjs b/fixtures/mjs-config-file-cjs/.size-limit.mjs
new file mode 100644
index 00000000..a086cba0
--- /dev/null
+++ b/fixtures/mjs-config-file-cjs/.size-limit.mjs
@@ -0,0 +1,5 @@
+module.exports = [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/mjs-config-file-cjs/index.js b/fixtures/mjs-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/mjs-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/mjs-config-file-cjs/package.json b/fixtures/mjs-config-file-cjs/package.json
new file mode 100644
index 00000000..d357038c
--- /dev/null
+++ b/fixtures/mjs-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "mjs-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/mjs-config-file-esm/.size-limit.mjs b/fixtures/mjs-config-file-esm/.size-limit.mjs
new file mode 100644
index 00000000..31503c8c
--- /dev/null
+++ b/fixtures/mjs-config-file-esm/.size-limit.mjs
@@ -0,0 +1,5 @@
+export default [
+  {
+    path: 'index.js'
+  }
+]
diff --git a/fixtures/mjs-config-file-esm/index.js b/fixtures/mjs-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/mjs-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/mjs-config-file-esm/package.json b/fixtures/mjs-config-file-esm/package.json
new file mode 100644
index 00000000..3ff83294
--- /dev/null
+++ b/fixtures/mjs-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "mjs-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/mts-config-file-cjs/.size-limit.mts b/fixtures/mts-config-file-cjs/.size-limit.mts
new file mode 100644
index 00000000..a759eaa9
--- /dev/null
+++ b/fixtures/mts-config-file-cjs/.size-limit.mts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+module.exports = [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/mts-config-file-cjs/index.js b/fixtures/mts-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/mts-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/mts-config-file-cjs/package.json b/fixtures/mts-config-file-cjs/package.json
new file mode 100644
index 00000000..bd5f91b3
--- /dev/null
+++ b/fixtures/mts-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "mts-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/mts-config-file-esm/.size-limit.mts b/fixtures/mts-config-file-esm/.size-limit.mts
new file mode 100644
index 00000000..99ffbf69
--- /dev/null
+++ b/fixtures/mts-config-file-esm/.size-limit.mts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+export default [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/mts-config-file-esm/index.js b/fixtures/mts-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/mts-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/mts-config-file-esm/package.json b/fixtures/mts-config-file-esm/package.json
new file mode 100644
index 00000000..39671c99
--- /dev/null
+++ b/fixtures/mts-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "mts-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/mts-config-file/.size-limit.mts b/fixtures/mts-config-file/.size-limit.mts
new file mode 100644
index 00000000..99ffbf69
--- /dev/null
+++ b/fixtures/mts-config-file/.size-limit.mts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+export default [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/mts-config-file/index.js b/fixtures/mts-config-file/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/mts-config-file/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/mts-config-file/package.json b/fixtures/mts-config-file/package.json
new file mode 100644
index 00000000..a15a9469
--- /dev/null
+++ b/fixtures/mts-config-file/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "mts-config-file",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/ts-config-file-cjs/.size-limit.ts b/fixtures/ts-config-file-cjs/.size-limit.ts
new file mode 100644
index 00000000..a759eaa9
--- /dev/null
+++ b/fixtures/ts-config-file-cjs/.size-limit.ts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+module.exports = [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/ts-config-file-cjs/index.js b/fixtures/ts-config-file-cjs/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/ts-config-file-cjs/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/ts-config-file-cjs/package.json b/fixtures/ts-config-file-cjs/package.json
new file mode 100644
index 00000000..c532dc5d
--- /dev/null
+++ b/fixtures/ts-config-file-cjs/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "ts-config-file-cjs",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/ts-config-file-esm/.size-limit.ts b/fixtures/ts-config-file-esm/.size-limit.ts
new file mode 100644
index 00000000..99ffbf69
--- /dev/null
+++ b/fixtures/ts-config-file-esm/.size-limit.ts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+export default [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/ts-config-file-esm/index.js b/fixtures/ts-config-file-esm/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/ts-config-file-esm/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/ts-config-file-esm/package.json b/fixtures/ts-config-file-esm/package.json
new file mode 100644
index 00000000..d7316959
--- /dev/null
+++ b/fixtures/ts-config-file-esm/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "ts-config-file-esm",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/ts-config-file-with-type-module/.size-limit.ts b/fixtures/ts-config-file-with-type-module/.size-limit.ts
new file mode 100644
index 00000000..99ffbf69
--- /dev/null
+++ b/fixtures/ts-config-file-with-type-module/.size-limit.ts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+export default [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/ts-config-file-with-type-module/index.js b/fixtures/ts-config-file-with-type-module/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/ts-config-file-with-type-module/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/ts-config-file-with-type-module/package.json b/fixtures/ts-config-file-with-type-module/package.json
new file mode 100644
index 00000000..33d7002e
--- /dev/null
+++ b/fixtures/ts-config-file-with-type-module/package.json
@@ -0,0 +1,10 @@
+{
+  "private": true,
+  "name": "ts-config-file-with-type-module",
+  "type": "module",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/fixtures/ts-config-file/.size-limit.ts b/fixtures/ts-config-file/.size-limit.ts
new file mode 100644
index 00000000..a759eaa9
--- /dev/null
+++ b/fixtures/ts-config-file/.size-limit.ts
@@ -0,0 +1,7 @@
+import { SizeLimitConfig } from '../../packages/size-limit'
+
+module.exports = [
+  {
+    path: 'index.js'
+  }
+] satisfies SizeLimitConfig
diff --git a/fixtures/ts-config-file/index.js b/fixtures/ts-config-file/index.js
new file mode 100644
index 00000000..d1bdfc55
--- /dev/null
+++ b/fixtures/ts-config-file/index.js
@@ -0,0 +1,5 @@
+const first = 'first'
+
+const second = 'second'
+
+export { first, second }
diff --git a/fixtures/ts-config-file/package.json b/fixtures/ts-config-file/package.json
new file mode 100644
index 00000000..f80c1f10
--- /dev/null
+++ b/fixtures/ts-config-file/package.json
@@ -0,0 +1,9 @@
+{
+  "private": true,
+  "name": "ts-config-file",
+  "devDependencies": {
+    "@size-limit/webpack": ">= 0.0.0",
+    "@size-limit/webpack-why": ">= 0.0.0",
+    "size-limit": ">= 0.0.0"
+  }
+}
diff --git a/packages/size-limit/get-config.js b/packages/size-limit/get-config.js
index 6cbd6509..7b4e2c8c 100644
--- a/packages/size-limit/get-config.js
+++ b/packages/size-limit/get-config.js
@@ -3,6 +3,7 @@ import { globby } from 'globby'
 import { lilconfig } from 'lilconfig'
 import { createRequire } from 'node:module'
 import { dirname, isAbsolute, join, relative } from 'node:path'
+import { fileURLToPath } from 'node:url'
 
 import { SizeLimitError } from './size-limit-error.js'
 
@@ -91,6 +92,23 @@ function toName(files, cwd) {
  */
 const dynamicImport = async filePath => (await import(filePath)).default
 
+/**
+ * Loads a TypeScript file from a given file path using the
+ * {@linkcode jiti} function. This loader function simplifies the
+ * process of dynamically importing TypeScript modules at runtime,
+ * offering a way to execute or import TypeScript files directly
+ * without pre-compilation.
+ *
+ * @param {string} filePath - The path to the TypeScript file to be loaded.
+ * @returns {Promise<any>} The module exports from the loaded TypeScript file.
+ */
+const tsLoader = async filePath => {
+  let jiti = (await import('jiti')).default(fileURLToPath(import.meta.url), {
+    interopDefault: true
+  })
+  return jiti(filePath)
+}
+
 export default async function getConfig(plugins, process, args, pkg) {
   let config = {
     cwd: process.cwd()
@@ -122,8 +140,12 @@ export default async function getConfig(plugins, process, args, pkg) {
   } else {
     let explorer = lilconfig('size-limit', {
       loaders: {
+        '.cjs': dynamicImport,
+        '.cts': tsLoader,
         '.js': dynamicImport,
-        '.mjs': dynamicImport
+        '.mjs': dynamicImport,
+        '.mts': tsLoader,
+        '.ts': tsLoader
       },
       searchPlaces: [
         'package.json',
@@ -131,7 +153,10 @@ export default async function getConfig(plugins, process, args, pkg) {
         '.size-limit',
         '.size-limit.js',
         '.size-limit.mjs',
-        '.size-limit.cjs'
+        '.size-limit.cjs',
+        '.size-limit.ts',
+        '.size-limit.mts',
+        '.size-limit.cts'
       ]
     })
     let result = await explorer.search(process.cwd())
diff --git a/packages/size-limit/index.d.ts b/packages/size-limit/index.d.ts
new file mode 100644
index 00000000..0caa2262
--- /dev/null
+++ b/packages/size-limit/index.d.ts
@@ -0,0 +1,120 @@
+/**
+ * Represents the options for the size-limit check.
+ */
+export interface Check {
+  /**
+   * With `false` it will disable any compression.
+   */
+  brotli?: boolean
+
+  /**
+   * Path to `stats.json` from another build to compare (when `--why` is using).
+   */
+  compareWith?: string
+
+  /**
+   * A path to a custom webpack config.
+   */
+  config?: string
+
+  disableModuleConcatenation?: boolean
+
+  /**
+   * When using a custom webpack config, a webpack entry could be given.
+   * It could be a string or an array of strings. By default,
+   * the total size of all entry points will be checked.
+   */
+  entry?: string | string[]
+
+  /**
+   * With `true` it will use Gzip compression and disable Brotli compression.
+   */
+  gzip?: boolean
+
+  hidePassed?: boolean
+
+  highlightLess?: boolean
+
+  /**
+   * An array of files and dependencies to exclude from
+   * the project size calculation.
+   */
+  ignore?: string[]
+
+  /**
+   * Partial import to test tree-shaking. It could be `"{ lib }"` to test
+   * `import { lib } from 'lib'`, `*` to test all exports, or
+   * `{ "a.js": "{ a }", "b.js": "{ b }" }` to test multiple files.
+   */
+  import?: string | Record<string, string>
+
+  /**
+   * Size or time limit for files from the path option.
+   * It should be a string with a number and unit, separated by a space.
+   * Format: `100 B`, `10 kB`, `500 ms`, `1 s`.
+   */
+  limit?: string
+
+  modifyEsbuildConfig?: (config?: any) => any
+
+  /**
+   * (`.size-limit.js` only) Function that can be used to do last-minute
+   * changes to the webpack config, like adding a plugin.
+   */
+  modifyWebpackConfig?: (config?: any) => any
+
+  module?: boolean
+
+  /**
+   * The name of the current section.
+   * It will only be useful if you have multiple sections.
+   */
+  name?: string
+
+  /**
+   * Relative paths to files. The only mandatory option.
+   * It could be a path `"index.js"`, a
+   * {@link https://github.com/sindresorhus/globby#globbing-patterns pattern}
+   * `"dist/app-*.js"` or an array
+   * `["index.js", "dist/app-*.js", "!dist/app-exclude.js"]`.
+   */
+  path: string | string[]
+
+  /**
+   * With `false` it will disable calculating running time.
+   */
+  running?: boolean
+
+  /**
+   * Custom UI reports list.
+   *
+   * @see {@link https://github.com/statoscope/statoscope/tree/master/packages/webpack-plugin#optionsreports-report Statoscope docs}
+   */
+  uiReports?: object
+
+  /**
+   * With `false` it will disable webpack.
+   */
+  webpack?: boolean
+}
+
+export type SizeLimitConfig = Check[]
+
+/**
+ * Any function with any arguments.
+ */
+type AnyFunction = (...args: any[]) => any
+
+/**
+ * Run Size Limit and return the result.
+ *
+ * @param plugins   The list of plugins like `@size-limit/time`
+ * @param  files Path to files or internal config
+ * @return Project size
+ */
+declare function sizeLimitAPI(
+  plugins: AnyFunction,
+  files: string[] | object
+): Promise<object>
+
+export default sizeLimitAPI
diff --git a/packages/size-limit/index.js b/packages/size-limit/index.js
index 8e88cb43..a9bd321e 100644
--- a/packages/size-limit/index.js
+++ b/packages/size-limit/index.js
@@ -8,7 +8,7 @@ export { SizeLimitError } from './size-limit-error.js'
 /**
  * Run Size Limit and return the result
  *
- * @param  {functions[]} plugins   The list of plugins like `@size-limit/time`
+ * @param  {Function[]} plugins   The list of plugins like `@size-limit/time`
  * @param  {string[]|object} files Path to files or internal config
  * @return {Promise<object>}     Project size
  */
diff --git a/packages/size-limit/package.json b/packages/size-limit/package.json
index 3eed7a24..919a1cbf 100644
--- a/packages/size-limit/package.json
+++ b/packages/size-limit/package.json
@@ -3,6 +3,7 @@
   "version": "11.0.3",
   "description": "CLI tool for Size Limit",
   "type": "module",
+  "types": "index.d.ts",
   "keywords": [
     "size-limit",
     "cli",
@@ -26,6 +27,7 @@
     "bytes-iec": "^3.1.1",
     "chokidar": "^3.6.0",
     "globby": "^14.0.1",
+    "jiti": "^1.21.0",
     "lilconfig": "^3.1.1",
     "nanospinner": "^1.1.0",
     "picocolors": "^1.0.0"
diff --git a/packages/size-limit/test/get-config.test.js b/packages/size-limit/test/get-config.test.js
index 46417811..fb627b1c 100644
--- a/packages/size-limit/test/get-config.test.js
+++ b/packages/size-limit/test/get-config.test.js
@@ -1,5 +1,5 @@
 import { join } from 'node:path'
-import { beforeEach, expect, it, vi } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import calc from '../calc'
 import run from '../run'
@@ -195,7 +195,7 @@ it('normalizes bundle and webpack arguments with --why and ui-reports', async ()
   })
 })
 
-it('should work with .mjs config file', async () => {
+it('works with .mjs config file', async () => {
   expect(await check('mjs-config-file')).toEqual({
     checks: [
       {
@@ -209,7 +209,7 @@ it('should work with .mjs config file', async () => {
   })
 })
 
-it('should work with .js config file', async () => {
+it('works with .js config file', async () => {
   expect(await check('js-config-file')).toEqual({
     checks: [
       {
@@ -223,7 +223,7 @@ it('should work with .js config file', async () => {
   })
 })
 
-it('should work with .js config file and "type": "module"', async () => {
+it('works with .js config file and "type": "module"', async () => {
   expect(await check('js-config-file-with-type-module')).toEqual({
     checks: [
       {
@@ -237,6 +237,118 @@ it('should work with .js config file and "type": "module"', async () => {
   })
 })
 
+it('works with .js config file and `export default` without "type": "module"', async () => {
+  expect(await check('js-config-file-esm')).toEqual({
+    checks: [
+      {
+        files: [fixture('js-config-file-esm', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.js',
+    cwd: fixture('js-config-file-esm')
+  })
+})
+
+it('works with .cjs config file and `export default` without "type": "module"', async () => {
+  expect(await check('cjs-config-file-esm')).toEqual({
+    checks: [
+      {
+        files: [fixture('cjs-config-file-esm', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.cjs',
+    cwd: fixture('cjs-config-file-esm')
+  })
+})
+
+it('works with .cjs config file and `module.exports` without "type": "module"', async () => {
+  expect(await check('cjs-config-file-cjs')).toEqual({
+    checks: [
+      {
+        files: [fixture('cjs-config-file-cjs', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.cjs',
+    cwd: fixture('cjs-config-file-cjs')
+  })
+})
+
+it('works with .ts config file and `export default` without "type": "module"', async () => {
+  expect(await check('ts-config-file-esm')).toEqual({
+    checks: [
+      {
+        files: [fixture('ts-config-file-esm', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.ts',
+    cwd: fixture('ts-config-file-esm')
+  })
+})
+
+it('works with .ts config file', async () => {
+  expect(await check('ts-config-file')).toEqual({
+    checks: [
+      {
+        files: [fixture('ts-config-file', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.ts',
+    cwd: fixture('ts-config-file')
+  })
+})
+
+it('works with .cts config file', async () => {
+  expect(await check('cts-config-file')).toEqual({
+    checks: [
+      {
+        files: [fixture('cts-config-file', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.cts',
+    cwd: fixture('cts-config-file')
+  })
+})
+
+it('works with .mts config file', async () => {
+  expect(await check('mts-config-file')).toEqual({
+    checks: [
+      {
+        files: [fixture('mts-config-file', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.mts',
+    cwd: fixture('mts-config-file')
+  })
+})
+
+it('works with .ts config file and "type": "module"', async () => {
+  expect(await check('ts-config-file-with-type-module')).toEqual({
+    checks: [
+      {
+        files: [fixture('ts-config-file-with-type-module', 'index.js')],
+        name: 'index.js',
+        path: 'index.js'
+      }
+    ],
+    configPath: '.size-limit.ts',
+    cwd: fixture('ts-config-file-with-type-module')
+  })
+})
+
 it('uses peerDependencies as ignore option', async () => {
   expect(await check('peer')).toEqual({
     checks: [
@@ -316,3 +428,33 @@ it('normalizes import', async () => {
     cwd: fixture('integration-esm')
   })
 })
+
+const allConfigFileExtensions = ['mjs', 'js', 'cjs', 'ts', 'mts', 'cts']
+const exportTypes = [
+  { exportSyntax: 'export default', moduleType: 'esm' },
+  { exportSyntax: 'module.exports', moduleType: 'cjs' }
+]
+
+describe.each(allConfigFileExtensions)(
+  'config file with `.%s` extension',
+  extension => {
+    it.each(exportTypes)(
+      'works with $moduleType module syntax ($exportSyntax)',
+      async ({ moduleType }) => {
+        expect(await check(`${extension}-config-file-${moduleType}`)).toEqual({
+          checks: [
+            {
+              files: [
+                fixture(`${extension}-config-file-${moduleType}`, 'index.js')
+              ],
+              name: 'index.js',
+              path: 'index.js'
+            }
+          ],
+          configPath: `.size-limit.${extension}`,
+          cwd: fixture(`${extension}-config-file-${moduleType}`)
+        })
+      }
+    )
+  }
+)
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index ce1c47f8..039dec0e 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -166,6 +166,9 @@ importers:
       globby:
         specifier: ^14.0.1
         version: 14.0.1
+      jiti:
+        specifier: ^1.21.0
+        version: 1.21.0
       lilconfig:
         specifier: ^3.1.1
         version: 3.1.1
@@ -3675,6 +3678,11 @@ packages:
       supports-color: 8.1.1
     dev: false
 
+  /jiti@1.21.0:
+    resolution: {integrity: sha512-gFqAIbuKyyso/3G2qhiO2OM6shY6EPP/R0+mkDbyspxKazh8BXDC5FiFsUjlczgdNz/vfra0da2y+aHrusLG/Q==}
+    hasBin: true
+    dev: false
+
   /jora@1.0.0-beta.8:
     resolution: {integrity: sha512-f3WpYwfDTlhfSdyCkAlAXSKRpwZYBgCDnyWmA9D0yyItCTFnFefKtvFpaczrj/FItkgDkHiewgFuHsgh4TmokA==}
     engines: {node: ^10.12.0 || ^12.20.0 || ^14.13.0 || >=15.0.0}
diff --git a/vite.config.ts b/vite.config.ts
index 96f0bfb8..34e7b873 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -1,4 +1,4 @@
-import { defineConfig } from 'vitest/config'
+import { coverageConfigDefaults, defineConfig } from 'vitest/config'
 
 export default defineConfig({
   test: {
@@ -11,6 +11,7 @@ export default defineConfig({
       skipFull: true,
       clean: true,
       exclude: [
+        ...coverageConfigDefaults.exclude,
         '**/fixtures',
         '**/scripts',
         '**/test',
@@ -18,7 +19,9 @@ export default defineConfig({
         'packages/preset-app/index.js'
       ]
     },
-    testTimeout: 10000,
-    watchExclude: ['**/fixtures', '**/dist', '**/out']
-  }
+    testTimeout: 20_000,
+    retry: process.env.CI ? 1 : 0,
+    fileParallelism: !process.env.CI
+  },
+  server: { watch: { ignored: ['**/fixtures', '**/dist', '**/out'] } }
 })