diff --git a/package.json b/package.json
index 2b0771a..7c48bab 100644
--- a/package.json
+++ b/package.json
@@ -70,8 +70,5 @@
     "typescript": "5.6.3",
     "vitest": "2.1.5",
     "vitest-github-actions-reporter": "0.11.1"
-  },
-  "dependencies": {
-    "ua-parser-js": "^1.0.32"
   }
 }
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 056cb53..19bb421 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -7,10 +7,6 @@ settings:
 importers:
 
   .:
-    dependencies:
-      ua-parser-js:
-        specifier: ^1.0.32
-        version: 1.0.39
     devDependencies:
       '@rollup/plugin-typescript':
         specifier: 12.1.1
@@ -1393,10 +1389,6 @@ packages:
     engines: {node: '>=14.17'}
     hasBin: true
 
-  ua-parser-js@1.0.39:
-    resolution: {integrity: sha512-k24RCVWlEcjkdOxYmVJgeD/0a1TiSpqLg+ZalVGV9lsnr4yqu0w7tX/x2xX6G4zpkgQnRf89lxuZ1wsbjXM8lw==}
-    hasBin: true
-
   uglify-js@3.19.3:
     resolution: {integrity: sha512-v3Xu+yuwBXisp6QYTcH4UbH+xYJXqnq2m/LtQVWKWzYc1iehYnLixoQDN9FH6/j9/oybfd6W9Ghwkl8+UMKTKQ==}
     engines: {node: '>=0.8.0'}
@@ -2756,8 +2748,6 @@ snapshots:
 
   typescript@5.6.3: {}
 
-  ua-parser-js@1.0.39: {}
-
   uglify-js@3.19.3:
     optional: true
 
diff --git a/src/browser-context.ts b/src/browser-context.ts
index 596299f..266aed6 100644
--- a/src/browser-context.ts
+++ b/src/browser-context.ts
@@ -1,18 +1,7 @@
 import { ExtendedClientApi, Plugin } from './client';
 import { BugsnagEvent } from './event';
 import { parseUserAgent } from './simple-ua-parser';
-
-export type UserAgentInfo = {
-  browserName?: string;
-  browserVersion?: string;
-  osName?: string;
-  osVersion?: string;
-  manufacturer?: string;
-  model?: string;
-  modelNumber?: string;
-};
-
-export type UserAgentParserFn = (userAgent: string) => UserAgentInfo;
+import type { UserAgentParserFn } from './user-agent-types';
 
 export const browserContextWithUaParser = (
   uaParser: UserAgentParserFn
diff --git a/src/index.ts b/src/index.ts
index 5e3c603..2427c4e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -344,12 +344,7 @@ export { nodeNotifyUnhandledExceptions } from './node-unhandled-exceptions';
 
 // Other plugins
 export { appDuration } from './app-duration';
-export {
-  browserContext,
-  browserContextWithUaParser,
-  UserAgentParserFn,
-  UserAgentInfo,
-} from './browser-context';
+export { browserContext, browserContextWithUaParser } from './browser-context';
 export { deviceOrientation } from './deviceorientation';
 export { limitEvents } from './limit-events';
 export {
@@ -365,6 +360,7 @@ export {
   redactObject,
 } from './redact-keys';
 export { stringifyValues } from './stringify-values';
+export type { UserAgentParserFn, UserAgentInfo } from './user-agent-types';
 
 // Delivery plugins
 export { FetchDelivery } from './fetch-delivery';
diff --git a/src/lambda-context.ts b/src/lambda-context.ts
index 2fb0660..081c1d4 100644
--- a/src/lambda-context.ts
+++ b/src/lambda-context.ts
@@ -4,11 +4,12 @@ import {
   Context,
 } from 'aws-lambda';
 import { platform as osPlatform, release as osRelease } from 'os';
-import UAParser from 'ua-parser-js';
 
 import { ExtendedClientApi, Plugin } from './client';
 import { BugsnagEvent } from './event';
+import { parseUserAgent } from './simple-ua-parser';
 import { toExceptions } from './to-exceptions';
+import { UserAgentParserFn } from './user-agent-types';
 
 export interface LambdaContextPlugin {
   setContext(
@@ -22,7 +23,8 @@ export interface LambdaContextPlugin {
   };
 }
 
-export const lambdaContext = (
+export const lambdaContextWithUaParser = (
+  uaParser: UserAgentParserFn,
   initialEvent?: Record<string, any>,
   initialContext?: Context
 ): Plugin => {
@@ -157,9 +159,7 @@ export const lambdaContext = (
             lambdaEvent.requestContext.identity.userAgent || undefined;
         }
 
-        const browser = userAgent
-          ? new UAParser(userAgent).getBrowser()
-          : undefined;
+        const browser = userAgent ? uaParser(userAgent) : undefined;
         const hostname = lambdaEvent?.requestContext?.domainName;
 
         let timeEpoch: number | undefined;
@@ -171,12 +171,15 @@ export const lambdaContext = (
 
         event.device = {
           hostname,
-          osName: osPlatform(),
-          osVersion: osRelease(),
+          osName: browser?.osName || osPlatform(),
+          osVersion: browser?.osVersion || osRelease(),
           freeMemory,
           totalMemory,
-          browserName: browser?.name,
-          browserVersion: browser?.version,
+          browserName: browser?.browserName,
+          browserVersion: browser?.browserVersion,
+          manufacturer: browser?.manufacturer,
+          model: browser?.model,
+          modelNumber: browser?.modelNumber,
           runtimeVersions: {
             node: process.version,
           },
@@ -284,6 +287,17 @@ export const lambdaContext = (
   };
 };
 
+export const lambdaContext = (
+  initialEvent?: Record<string, any>,
+  initialContext?: Context
+): Plugin => {
+  return lambdaContextWithUaParser(
+    parseUserAgent,
+    initialEvent,
+    initialContext
+  );
+};
+
 function isGwV2Event(
   event: Record<string, any> | undefined
 ): event is APIGatewayProxyEventV2 {
diff --git a/src/simple-ua-parser.ts b/src/simple-ua-parser.ts
index 72d9380..b805ad5 100644
--- a/src/simple-ua-parser.ts
+++ b/src/simple-ua-parser.ts
@@ -1,4 +1,4 @@
-import { UserAgentInfo } from './browser-context';
+import type { UserAgentInfo } from './user-agent-types';
 
 // The Bugsnag v5 API requires doing your own UA string parsing, requiring a
 // `browserName`, `browserVersion`, `osName`, `osVersion`, etc.
diff --git a/src/user-agent-types.ts b/src/user-agent-types.ts
new file mode 100644
index 0000000..cfdb13b
--- /dev/null
+++ b/src/user-agent-types.ts
@@ -0,0 +1,11 @@
+export type UserAgentInfo = {
+  browserName?: string;
+  browserVersion?: string;
+  osName?: string;
+  osVersion?: string;
+  manufacturer?: string;
+  model?: string;
+  modelNumber?: string;
+};
+
+export type UserAgentParserFn = (userAgent: string) => UserAgentInfo;