diff --git a/.changeset/beige-foxes-compare.md b/.changeset/beige-foxes-compare.md
new file mode 100644
index 00000000000..ffae682bb1d
--- /dev/null
+++ b/.changeset/beige-foxes-compare.md
@@ -0,0 +1,5 @@
+---
+"@hyperlane-xyz/utils": patch
+---
+
+Use stringifyObject in writeJson and writeYaml for proper ethers BigNumber serialization. Rename removeEndingSlash to removeTrailingSlash.
diff --git a/typescript/cli/src/commands/warp.ts b/typescript/cli/src/commands/warp.ts
index 58226613caa..6d2a3ff20c4 100644
--- a/typescript/cli/src/commands/warp.ts
+++ b/typescript/cli/src/commands/warp.ts
@@ -41,7 +41,7 @@ import { ExtendedChainSubmissionStrategySchema } from '../submitters/types.js';
 import {
   indentYamlOrJson,
   readYamlOrJson,
-  removeEndingSlash,
+  removeTrailingSlash,
   writeYamlOrJson,
 } from '../utils/files.js';
 import {
@@ -123,7 +123,7 @@ export const apply: CommandModuleWithWarpApplyContext<
       type: 'string',
       description: 'The directory to output transaction receipts.',
       default: './generated/transactions',
-      coerce: (dir) => removeEndingSlash(dir),
+      coerce: (dir) => removeTrailingSlash(dir),
     },
     relay: {
       type: 'boolean',
diff --git a/typescript/cli/src/utils/files.ts b/typescript/cli/src/utils/files.ts
index 35aa3ab8b12..951ae37118f 100644
--- a/typescript/cli/src/utils/files.ts
+++ b/typescript/cli/src/utils/files.ts
@@ -15,7 +15,7 @@ import {
   readJson,
   readYaml,
   readYamlOrJson,
-  removeEndingSlash,
+  removeTrailingSlash,
   resolveFileFormat,
   resolvePath,
   tryReadJson,
@@ -36,7 +36,7 @@ export {
   isFile,
   readFileAtPath,
   writeFileAtPath,
-  removeEndingSlash,
+  removeTrailingSlash,
   resolvePath,
   readJson,
   tryReadJson,
diff --git a/typescript/utils/src/fs/index.ts b/typescript/utils/src/fs/index.ts
index ca01d12f9af..3f0b82b94c9 100644
--- a/typescript/utils/src/fs/index.ts
+++ b/typescript/utils/src/fs/index.ts
@@ -8,7 +8,7 @@ export {
   isFile,
   pathExists,
   readFileAtPath,
-  removeEndingSlash,
+  removeTrailingSlash,
   resolvePath,
   writeFileAtPath,
   writeToFile,
diff --git a/typescript/utils/src/fs/json.ts b/typescript/utils/src/fs/json.ts
index d4c48a34902..652fcadcdcd 100644
--- a/typescript/utils/src/fs/json.ts
+++ b/typescript/utils/src/fs/json.ts
@@ -1,6 +1,6 @@
 import path from 'path';
 
-import { objMerge } from '../objects.js';
+import { objMerge, stringifyObject } from '../objects.js';
 
 import { isFile, pathExists, readFileAtPath, writeToFile } from './utils.js';
 
@@ -24,9 +24,10 @@ export function tryReadJson<T>(filepath: string): T | null {
 
 /**
  * Writes an object as JSON to a file with a trailing newline.
+ * Uses stringifyObject to properly handle ethers BigNumber serialization.
  */
 export function writeJson(filepath: string, obj: unknown): void {
-  writeToFile(filepath, JSON.stringify(obj, null, 2));
+  writeToFile(filepath, stringifyObject(obj, 'json', 2));
 }
 
 /**
diff --git a/typescript/utils/src/fs/utils.test.ts b/typescript/utils/src/fs/utils.test.ts
index fcd3fa225f0..4d0427fe176 100644
--- a/typescript/utils/src/fs/utils.test.ts
+++ b/typescript/utils/src/fs/utils.test.ts
@@ -8,7 +8,7 @@ import {
   isFile,
   pathExists,
   readFileAtPath,
-  removeEndingSlash,
+  removeTrailingSlash,
   resolvePath,
   writeFileAtPath,
   writeToFile,
@@ -32,17 +32,17 @@ describe('fs utilities', () => {
     }
   });
 
-  describe('removeEndingSlash', () => {
+  describe('removeTrailingSlash', () => {
     it('removes trailing slash', () => {
-      expect(removeEndingSlash('/path/to/dir/')).to.equal('/path/to/dir');
+      expect(removeTrailingSlash('/path/to/dir/')).to.equal('/path/to/dir');
     });
 
     it('leaves path without trailing slash unchanged', () => {
-      expect(removeEndingSlash('/path/to/dir')).to.equal('/path/to/dir');
+      expect(removeTrailingSlash('/path/to/dir')).to.equal('/path/to/dir');
     });
 
     it('handles empty string', () => {
-      expect(removeEndingSlash('')).to.equal('');
+      expect(removeTrailingSlash('')).to.equal('');
     });
   });
 
diff --git a/typescript/utils/src/fs/utils.ts b/typescript/utils/src/fs/utils.ts
index 789373c330a..c8f6f463805 100644
--- a/typescript/utils/src/fs/utils.ts
+++ b/typescript/utils/src/fs/utils.ts
@@ -5,7 +5,7 @@ import path from 'path';
 /**
  * Removes trailing slash from a directory path.
  */
-export function removeEndingSlash(dirPath: string): string {
+export function removeTrailingSlash(dirPath: string): string {
   if (dirPath.endsWith('/')) {
     return dirPath.slice(0, -1);
   }
diff --git a/typescript/utils/src/fs/yaml.ts b/typescript/utils/src/fs/yaml.ts
index e90b5efafb9..35a6da464b3 100644
--- a/typescript/utils/src/fs/yaml.ts
+++ b/typescript/utils/src/fs/yaml.ts
@@ -5,10 +5,9 @@ import {
   SchemaOptions,
   ToJSOptions,
   parse,
-  stringify as yamlStringify,
 } from 'yaml';
 
-import { objMerge } from '../objects.js';
+import { objMerge, stringifyObject } from '../objects.js';
 
 import { isFile, readFileAtPath, writeToFile } from './utils.js';
 
@@ -45,12 +44,10 @@ export function tryReadYaml<T>(filepath: string): T | null {
 
 /**
  * Writes an object as YAML to a file with a trailing newline.
+ * Uses stringifyObject to properly handle ethers BigNumber serialization.
  */
 export function writeYaml(filepath: string, obj: unknown): void {
-  writeToFile(
-    filepath,
-    yamlStringify(obj, { indent: 2, sortMapEntries: true }).trimEnd(),
-  );
+  writeToFile(filepath, stringifyObject(obj, 'yaml', 2).trimEnd());
 }
 
 /**