diff --git a/src/feature_flags.ts b/src/feature_flags.ts
index 25f077cb7..0cd33922a 100644
--- a/src/feature_flags.ts
+++ b/src/feature_flags.ts
@@ -1,11 +1,9 @@
 import { env } from 'process'
 
 export const defaultFlags: Record<string, boolean> = {
-  buildGoSource: Boolean(env.NETLIFY_EXPERIMENTAL_BUILD_GO_SOURCE),
   buildRustSource: Boolean(env.NETLIFY_EXPERIMENTAL_BUILD_RUST_SOURCE),
   parseWithEsbuild: false,
   traceWithNft: false,
-  zisi_detect_esm: false,
   zisi_pure_esm: false,
 }
 
diff --git a/src/runtimes/go/index.ts b/src/runtimes/go/index.ts
index 5bb431fc1..1c8de601f 100644
--- a/src/runtimes/go/index.ts
+++ b/src/runtimes/go/index.ts
@@ -44,17 +44,13 @@ const findFunctionsInPaths: FindFunctionsInPathsFunction = async function ({ fea
   return functions.filter(nonNullable)
 }
 
-const findFunctionInPath: FindFunctionInPathFunction = async function ({ featureFlags, fsCache, path }) {
+const findFunctionInPath: FindFunctionInPathFunction = async function ({ fsCache, path }) {
   const runtime = await detectBinaryRuntime({ fsCache, path })
 
   if (runtime === 'go') {
     return processBinary({ fsCache, path })
   }
 
-  if (featureFlags.buildGoSource !== true) {
-    return
-  }
-
   const goSourceFile = await detectGoFunction({ fsCache, path })
 
   if (goSourceFile) {
diff --git a/src/runtimes/node/bundlers/index.ts b/src/runtimes/node/bundlers/index.ts
index cf3de349c..cf20d545d 100644
--- a/src/runtimes/node/bundlers/index.ts
+++ b/src/runtimes/node/bundlers/index.ts
@@ -110,13 +110,7 @@ export const getDefaultBundler = async ({
     return 'nft'
   }
 
-  if (featureFlags.zisi_detect_esm) {
-    const functionIsESM = await detectEsModule({ mainFile })
+  const functionIsESM = await detectEsModule({ mainFile })
 
-    if (functionIsESM) {
-      return 'nft'
-    }
-  }
-
-  return 'zisi'
+  return functionIsESM ? 'nft' : 'zisi'
 }
diff --git a/tests/main.js b/tests/main.js
index c33f39ed5..d3960d941 100644
--- a/tests/main.js
+++ b/tests/main.js
@@ -462,7 +462,7 @@ testMany(
           nodeVersion: 'nodejs12.x',
         },
       },
-      featureFlags: { zisi_detect_esm: true, zisi_pure_esm: false },
+      featureFlags: { zisi_pure_esm: false },
     })
     const { files, tmpDir } = await zipFixture(t, fixtureName, {
       length,
@@ -517,7 +517,7 @@ testMany(
           nodeVersion: 'nodejs12.x',
         },
       },
-      featureFlags: { zisi_detect_esm: true, zisi_pure_esm: false },
+      featureFlags: { zisi_pure_esm: false },
     })
     const { tmpDir } = await zipFixture(t, fixtureName, {
       length,
@@ -559,11 +559,8 @@ testMany(
 testMany(
   'Can bundle CJS functions that import ESM files with an `import()` expression',
   ['bundler_default', 'bundler_esbuild', 'bundler_nft'],
-  async (options, t) => {
+  async (opts, t) => {
     const fixtureName = 'node-cjs-importing-mjs'
-    const opts = merge(options, {
-      featureFlags: { zisi_detect_esm: true },
-    })
     const { files, tmpDir } = await zipFixture(t, fixtureName, {
       opts,
     })
@@ -590,7 +587,7 @@ testMany(
     const fixtureName = 'node-esm'
     const opts = merge(options, {
       basePath: join(FIXTURES_DIR, fixtureName),
-      featureFlags: { zisi_detect_esm: true, zisi_pure_esm: true },
+      featureFlags: { zisi_pure_esm: true },
     })
     const { files, tmpDir } = await zipFixture(t, fixtureName, {
       length,
@@ -622,7 +619,6 @@ testMany(
     const fixtureName = 'node-esm'
     const opts = merge(options, {
       basePath: join(FIXTURES_DIR, fixtureName),
-      featureFlags: { zisi_detect_esm: true },
     })
     const { files, tmpDir } = await zipFixture(t, fixtureName, {
       length,
@@ -2226,9 +2222,6 @@ test.serial('Zips Go functions built from source if the `zipGo` config property
           zipGo: true,
         },
       },
-      featureFlags: {
-        buildGoSource: true,
-      },
     },
   })
   const [func] = files
@@ -2244,27 +2237,12 @@ test.serial('Zips Go functions built from source if the `zipGo` config property
   t.is(mockSource, unzippedBinaryContents)
 })
 
-test.serial('Does not build Go functions from source if the `buildGoSource` feature flag is not enabled', async (t) => {
-  shellUtilsStub.callsFake((...args) => writeFile(args[1][2], ''))
-
-  const fixtureName = 'go-source-multiple'
-  const { files } = await zipFixture(t, fixtureName, { length: 0 })
-
-  t.is(files.length, 0)
-  t.is(shellUtilsStub.callCount, 0)
-})
-
-test.serial('Builds Go functions from source if the `buildGoSource` feature flag is enabled', async (t) => {
+test.serial('Builds Go functions from source', async (t) => {
   shellUtilsStub.callsFake((...args) => writeFile(args[1][2], ''))
 
   const fixtureName = 'go-source-multiple'
   const { files } = await zipFixture(t, fixtureName, {
     length: 2,
-    opts: {
-      featureFlags: {
-        buildGoSource: true,
-      },
-    },
   })
 
   t.is(shellUtilsStub.callCount, 2)
@@ -2301,13 +2279,7 @@ test.serial('Adds `type: "functionsBundling"` to errors resulting from compiling
   })
 
   try {
-    await zipFixture(t, 'go-source', {
-      opts: {
-        featureFlags: {
-          buildGoSource: true,
-        },
-      },
-    })
+    await zipFixture(t, 'go-source')
 
     t.fail('Expected catch block')
   } catch (error) {
@@ -2640,7 +2612,6 @@ test('Generates a sourcemap for any transpiled files when `nodeSourcemap: true`'
       archiveFormat: 'none',
       basePath,
       config: { '*': { nodeBundler: 'nft', nodeSourcemap: true } },
-      featureFlags: { nftTranspile: true },
     },
   })
   const func = await importFunctionFile(join(files[0].path, 'function.js'))