diff --git a/fixup.cjs b/fixup.cjs
index 91b1830..c813406 100755
--- a/fixup.cjs
+++ b/fixup.cjs
@@ -24,7 +24,7 @@ const processFiles = (dir) => {
       processFiles(filePath);
     } else if (filePath.endsWith('.cjs')) {
       updateRequires(filePath);
-    } else if (filePath.endsWith('.js')) {
+    } else if (filePath.endsWith('.js') || filePath.endsWith('.d.ts')) {
       updateImports(filePath);
     }
   });
diff --git a/src/cjs/ecpair.d.ts b/src/cjs/ecpair.d.ts
index 6a2af67..a03b767 100644
--- a/src/cjs/ecpair.d.ts
+++ b/src/cjs/ecpair.d.ts
@@ -1,5 +1,5 @@
-import { Network } from './networks';
-import * as networks from './networks';
+import { Network } from './networks.js';
+import * as networks from './networks.js';
 export { networks };
 import * as v from 'valibot';
 declare const ECPairOptionsSchema: v.OptionalSchema<v.ObjectSchema<{
diff --git a/src/cjs/index.d.ts b/src/cjs/index.d.ts
index 2f603e5..024fcdb 100644
--- a/src/cjs/index.d.ts
+++ b/src/cjs/index.d.ts
@@ -1 +1 @@
-export { ECPairFactory as default, ECPairFactory, type Signer, type SignerAsync, type ECPairAPI, type ECPairInterface, type TinySecp256k1Interface, networks, } from './ecpair';
+export { ECPairFactory as default, ECPairFactory, type Signer, type SignerAsync, type ECPairAPI, type ECPairInterface, type TinySecp256k1Interface, networks, } from './ecpair.js';
diff --git a/src/cjs/networks.d.ts b/src/cjs/networks.d.ts
index 111ff40..e5939da 100644
--- a/src/cjs/networks.d.ts
+++ b/src/cjs/networks.d.ts
@@ -1,5 +1,5 @@
 import * as v from 'valibot';
-import { NetworkSchema } from './types';
+import { NetworkSchema } from './types.js';
 export type Network = v.InferOutput<typeof NetworkSchema>;
 export declare const bitcoin: Network;
 export declare const testnet: Network;
diff --git a/src/cjs/testecc.d.ts b/src/cjs/testecc.d.ts
index bff8d27..d568e57 100644
--- a/src/cjs/testecc.d.ts
+++ b/src/cjs/testecc.d.ts
@@ -1,2 +1,2 @@
-import { TinySecp256k1Interface } from './ecpair';
+import { TinySecp256k1Interface } from './ecpair.js';
 export declare function testEcc(ecc: TinySecp256k1Interface): void;