diff --git a/packages/backend/src/logger.ts b/packages/backend/src/logger.ts
index 46edac8666..b3735200eb 100644
--- a/packages/backend/src/logger.ts
+++ b/packages/backend/src/logger.ts
@@ -27,7 +27,7 @@ export type DataObject = Record<string, unknown> | (object & { length?: never; }
 export default class Logger {
 	private context: Context;
 	private parentLogger: Logger | null = null;
-	private readonly verbose: boolean;
+	public readonly verbose: boolean;
 
 	constructor(context: string, color?: KEYWORD, verbose?: boolean) {
 		this.context = {
diff --git a/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts b/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
index 359408d882..d95d75f12f 100644
--- a/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
+++ b/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
@@ -56,9 +56,12 @@ export class MastodonApiServerService {
 
 		// Log error responses (including converted JSON exceptions)
 		fastify.addHook('onSend', (request, reply, payload, done) => {
-			if (reply.statusCode >= 400) {
-				const data = getErrorData(payload);
-				this.logger.error(request, data, reply.statusCode);
+			if (reply.statusCode >= 500 || (reply.statusCode >= 400 && this.logger.verbose)) {
+				if (typeof(payload) === 'string' && String(reply.getHeader('content-type')).toLowerCase().includes('application/json')) {
+					const body = JSON.parse(payload);
+					const data = getErrorData(body);
+					this.logger.error(request, data, reply.statusCode);
+				}
 			}
 			done();
 		});
diff --git a/packages/backend/src/server/api/mastodon/MastodonLogger.ts b/packages/backend/src/server/api/mastodon/MastodonLogger.ts
index 096a3521a7..f43e2fc764 100644
--- a/packages/backend/src/server/api/mastodon/MastodonLogger.ts
+++ b/packages/backend/src/server/api/mastodon/MastodonLogger.ts
@@ -3,22 +3,22 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import { Inject, Injectable } from '@nestjs/common';
+import { Injectable } from '@nestjs/common';
 import { FastifyRequest } from 'fastify';
 import Logger from '@/logger.js';
 import { LoggerService } from '@/core/LoggerService.js';
 import { ApiError } from '@/server/api/error.js';
-import { EnvService } from '@/core/EnvService.js';
 import { getBaseUrl } from '@/server/api/mastodon/MastodonClientService.js';
 
 @Injectable()
 export class MastodonLogger {
 	public readonly logger: Logger;
 
-	constructor(
-		@Inject(EnvService)
-		private readonly envService: EnvService,
+	public get verbose() {
+		return this.logger.verbose;
+	}
 
+	constructor(
 		loggerService: LoggerService,
 	) {
 		this.logger = loggerService.getLogger('masto-api');