diff --git a/LICENSE-3rdparty.csv b/LICENSE-3rdparty.csv
index ed8366cb92..6337b0c46e 100644
--- a/LICENSE-3rdparty.csv
+++ b/LICENSE-3rdparty.csv
@@ -1,11 +1,7 @@
 Component,Origin,License,Copyright
-require,lodash.assign,MIT,Copyright jQuery Foundation and other contributors
-require,lodash.merge,MIT,Copyright OpenJS Foundation and other contributors
 require,tslib,Apache-2.0,Copyright Microsoft Corporation
 file,tracekit,MIT,Copyright 2013 Onur Can Cakmak and all TraceKit contributors
 dev,@types/jasmine,MIT,Copyright Microsoft Corporation
-dev,@types/lodash.assign,MIT,Copyright Microsoft Corporation
-dev,@types/lodash.merge,MIT,Copyright Microsoft Corporation
 dev,@types/request,MIT,Copyright Microsoft Corporation
 dev,@types/sinon,MIT,Copyright Microsoft Corporation
 dev,@wdio/browserstack-service,MIT,Copyright JS Foundation and other contributors
diff --git a/packages/core/package.json b/packages/core/package.json
index f99670c0fa..0313c72def 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -11,13 +11,9 @@
     "build:esm": "rm -rf esm && tsc -p tsconfig.esm.json"
   },
   "dependencies": {
-    "lodash.assign": "4.2.0",
-    "lodash.merge": "4.6.2",
     "tslib": "1.10.0"
   },
   "devDependencies": {
-    "@types/lodash.assign": "4.2.6",
-    "@types/lodash.merge": "4.6.6",
     "@types/sinon": "7.0.13",
     "sinon": "7.3.2"
   },
diff --git a/packages/core/src/internalMonitoring.ts b/packages/core/src/internalMonitoring.ts
index f244c63ee2..61b05f3b00 100644
--- a/packages/core/src/internalMonitoring.ts
+++ b/packages/core/src/internalMonitoring.ts
@@ -1,8 +1,4 @@
 // tslint:disable ban-types
-
-import lodashAssign from 'lodash.assign'
-import lodashMerge from 'lodash.merge'
-
 import { Configuration } from './configuration'
 import { toStackTraceString } from './errorCollection'
 import { computeStackTrace } from './tracekit'
@@ -45,7 +41,7 @@ export function startInternalMonitoring(configuration: Configuration): InternalM
       configuration.maxMessageSize,
       configuration.flushTimeout,
       () =>
-        lodashMerge(
+        utils.deepMerge(
           {
             date: new Date().getTime(),
             view: {
@@ -54,10 +50,10 @@ export function startInternalMonitoring(configuration: Configuration): InternalM
             },
           },
           externalContextProvider !== undefined ? externalContextProvider() : {}
-        )
+        ) as utils.Context
     )
 
-    lodashAssign(monitoringConfiguration, {
+    utils.assign(monitoringConfiguration, {
       batch,
       maxMessagesPerPage: configuration.maxInternalMonitoringMessagesPerPage,
       sentMessageCount: 0,
diff --git a/packages/core/src/transport.ts b/packages/core/src/transport.ts
index 5f68219370..ae381f5bfe 100644
--- a/packages/core/src/transport.ts
+++ b/packages/core/src/transport.ts
@@ -1,7 +1,5 @@
-import lodashMerge from 'lodash.merge'
-
 import { monitor } from './internalMonitoring'
-import { Context, DOM_EVENT, jsonStringify, noop, objectValues } from './utils'
+import { Context, deepMerge, DOM_EVENT, jsonStringify, noop, objectValues } from './utils'
 
 /**
  * Use POST request without content type to:
@@ -89,7 +87,7 @@ export class Batch<T> {
   }
 
   private process(message: T) {
-    const contextualizedMessage = lodashMerge({}, this.contextProvider(), message) as Context
+    const contextualizedMessage = deepMerge({}, this.contextProvider(), (message as unknown) as Context) as Context
     const processedMessage = jsonStringify(contextualizedMessage)!
     const messageBytesSize = this.sizeInBytes(processedMessage)
     return { processedMessage, messageBytesSize }
diff --git a/packages/core/src/utils.ts b/packages/core/src/utils.ts
index ad73808470..a3130f3c63 100644
--- a/packages/core/src/utils.ts
+++ b/packages/core/src/utils.ts
@@ -72,6 +72,52 @@ export function throttle(
   }
 }
 
+const isContextArray = (value: ContextValue): value is ContextArray => Array.isArray(value)
+const isContext = (value: ContextValue): value is Context => !Array.isArray(value) && typeof value === 'object'
+
+/**
+ * Performs a deep merge of objects and arrays
+ * - arrays values are merged index by index
+ * - objects are merged by keys
+ * - values get replaced, unless undefined
+ *
+ * ⚠️ this method does not prevent infinite loops while merging circular references ⚠️
+ *
+ */
+export function deepMerge(destination: ContextValue, ...toMerge: ContextValue[]): ContextValue {
+  return toMerge.reduce((value1: ContextValue, value2: ContextValue): ContextValue => {
+    if (isContextArray(value1) && isContextArray(value2)) {
+      return [...Array(Math.max(value1.length, value2.length))].map((_, index) =>
+        deepMerge(value1[index], value2[index])
+      )
+    }
+    if (isContext(value1) && isContext(value2)) {
+      return Object.keys(value2).reduce(
+        (merged, key) => ({
+          ...merged,
+          [key]: deepMerge(value1[key], value2[key]),
+        }),
+        value1
+      )
+    }
+    return value2 === undefined ? value1 : value2
+  }, destination)
+}
+
+interface Assignable {
+  [key: string]: any
+}
+
+export function assign(target: Assignable, ...toAssign: Assignable[]) {
+  toAssign.forEach((source: Assignable) => {
+    for (const key in source) {
+      if (Object.prototype.hasOwnProperty.call(source, key)) {
+        target[key] = source[key]
+      }
+    }
+  })
+}
+
 /**
  * UUID v4
  * from https://gist.github.com/jed/982883
diff --git a/packages/core/test/utils.spec.ts b/packages/core/test/utils.spec.ts
index aebcd51597..c29ba3b309 100644
--- a/packages/core/test/utils.spec.ts
+++ b/packages/core/test/utils.spec.ts
@@ -1,6 +1,24 @@
-import { jsonStringify, performDraw, round, throttle, toSnakeCase, withSnakeCaseKeys } from '../src/utils'
+import { deepMerge, jsonStringify, performDraw, round, throttle, toSnakeCase, withSnakeCaseKeys } from '../src/utils'
 
 describe('utils', () => {
+  describe('deepMerge', () => {
+    it('should deeply add and replace keys', () => {
+      const target = { a: { b: 'toBeReplaced', c: 'target' } }
+      const source = { a: { b: 'replaced', d: 'source' } }
+      expect(deepMerge(target, source)).toEqual({ a: { b: 'replaced', c: 'target', d: 'source' } })
+    })
+
+    it('should not replace with undefined', () => {
+      expect(deepMerge({ a: 1 }, { a: undefined })).toEqual({ a: 1 })
+    })
+
+    it('should merge arrays', () => {
+      const target = [{ a: 'target' }, 'extraString']
+      const source = [{ b: 'source' }]
+      expect(deepMerge(target, source)).toEqual([{ a: 'target', b: 'source' }, 'extraString'])
+    })
+  })
+
   describe('throttle', () => {
     let spy: jasmine.Spy
     let throttled: () => void
diff --git a/packages/logs/package.json b/packages/logs/package.json
index 9885169585..bc5d617990 100644
--- a/packages/logs/package.json
+++ b/packages/logs/package.json
@@ -14,13 +14,9 @@
   },
   "dependencies": {
     "@datadog/browser-core": "1.11.6",
-    "lodash.assign": "4.2.0",
-    "lodash.merge": "4.6.2",
     "tslib": "1.10.0"
   },
   "devDependencies": {
-    "@types/lodash.assign": "4.2.6",
-    "@types/lodash.merge": "4.6.6",
     "@types/sinon": "7.0.13",
     "sinon": "7.3.2"
   },
diff --git a/packages/logs/src/logger.ts b/packages/logs/src/logger.ts
index 2a8108a20a..9b80b796c4 100644
--- a/packages/logs/src/logger.ts
+++ b/packages/logs/src/logger.ts
@@ -3,6 +3,7 @@ import {
   Configuration,
   Context,
   ContextValue,
+  deepMerge,
   ErrorMessage,
   ErrorObservable,
   ErrorOrigin,
@@ -12,7 +13,6 @@ import {
   monitored,
   noop,
 } from '@datadog/browser-core'
-import lodashMerge from 'lodash.merge'
 
 import { LoggerSession } from './loggerSession'
 import { LogsGlobal } from './logs.entry'
@@ -61,8 +61,8 @@ export function startLogger(
 ) {
   let globalContext: Context = {}
 
-  internalMonitoring.setExternalContextProvider(() =>
-    lodashMerge({ session_id: session.getId() }, globalContext, getRUMInternalContext())
+  internalMonitoring.setExternalContextProvider(
+    () => deepMerge({ session_id: session.getId() }, globalContext, getRUMInternalContext() as Context) as Context
   )
 
   const batch = new Batch<LogsMessage>(
@@ -72,7 +72,7 @@ export function startLogger(
     configuration.maxMessageSize,
     configuration.flushTimeout,
     () =>
-      lodashMerge(
+      deepMerge(
         {
           date: new Date().getTime(),
           session_id: session.getId(),
@@ -82,7 +82,7 @@ export function startLogger(
           },
         },
         globalContext,
-        getRUMInternalContext()
+        getRUMInternalContext() as Context
       ) as Context
   )
   const handlers = {
@@ -141,7 +141,7 @@ export class Logger {
   @monitored
   log(message: string, messageContext = {}, status = StatusType.info) {
     if (this.session.isTracked() && STATUS_PRIORITIES[status] >= STATUS_PRIORITIES[this.level]) {
-      this.handler({ message, status, ...lodashMerge({}, this.loggerContext, messageContext) })
+      this.handler({ message, status, ...(deepMerge({}, this.loggerContext, messageContext) as Context) })
     }
   }
 
@@ -163,7 +163,7 @@ export class Logger {
         origin: ErrorOrigin.LOGGER,
       },
     }
-    this.log(message, lodashMerge({}, errorOrigin, messageContext), StatusType.error)
+    this.log(message, deepMerge({}, errorOrigin, messageContext), StatusType.error)
   }
 
   setContext(context: Context) {
diff --git a/packages/logs/src/logs.entry.ts b/packages/logs/src/logs.entry.ts
index 167fa283a9..61bb1c2e21 100644
--- a/packages/logs/src/logs.entry.ts
+++ b/packages/logs/src/logs.entry.ts
@@ -1,5 +1,6 @@
 import {
   areCookiesAuthorized,
+  assign,
   checkIsNotLocalFile,
   commonInit,
   Context,
@@ -11,7 +12,6 @@ import {
   monitor,
   UserConfiguration,
 } from '@datadog/browser-core'
-import lodashAssign from 'lodash.assign'
 import { buildEnv } from './buildEnv'
 import { HandlerType, Logger, LoggerConfiguration, startLogger, StatusType } from './logger'
 import { startLoggerSession } from './loggerSession'
@@ -94,7 +94,7 @@ datadogLogs.init = monitor((userConfiguration: LogsUserConfiguration) => {
   const { errorObservable, configuration, internalMonitoring } = commonInit(logsUserConfiguration, buildEnv)
   const session = startLoggerSession(configuration, areCookiesAuthorized())
   const globalApi = startLogger(errorObservable, configuration, session, internalMonitoring)
-  lodashAssign(datadogLogs, globalApi)
+  assign(datadogLogs, globalApi)
   isAlreadyInitialized = true
 })
 
diff --git a/packages/rum/package.json b/packages/rum/package.json
index 686226153e..72ef5694bd 100644
--- a/packages/rum/package.json
+++ b/packages/rum/package.json
@@ -14,13 +14,9 @@
   },
   "dependencies": {
     "@datadog/browser-core": "1.11.6",
-    "lodash.assign": "4.2.0",
-    "lodash.merge": "4.6.2",
     "tslib": "1.10.0"
   },
   "devDependencies": {
-    "@types/lodash.assign": "4.2.6",
-    "@types/lodash.merge": "4.6.6",
     "@types/sinon": "7.0.13",
     "sinon": "7.3.2"
   },
diff --git a/packages/rum/src/rum.entry.ts b/packages/rum/src/rum.entry.ts
index ab0d862c3e..daa4379d6b 100644
--- a/packages/rum/src/rum.entry.ts
+++ b/packages/rum/src/rum.entry.ts
@@ -1,4 +1,5 @@
 import {
+  assign,
   checkCookiesAuthorized,
   checkIsNotLocalFile,
   commonInit,
@@ -12,7 +13,6 @@ import {
   startRequestCollection,
   UserConfiguration,
 } from '@datadog/browser-core'
-import lodashAssign from 'lodash.assign'
 
 import { buildEnv } from './buildEnv'
 import { startDOMMutationCollection } from './domMutationCollection'
@@ -85,7 +85,7 @@ datadogRum.init = monitor((userConfiguration: RumUserConfiguration) => {
   requestStartObservable.subscribe((startEvent) => lifeCycle.notify(LifeCycleEventType.REQUEST_STARTED, startEvent))
   requestCompleteObservable.subscribe((request) => lifeCycle.notify(LifeCycleEventType.REQUEST_COMPLETED, request))
 
-  lodashAssign(datadogRum, globalApi)
+  assign(datadogRum, globalApi)
   isAlreadyInitialized = true
 })
 
diff --git a/packages/rum/src/rum.ts b/packages/rum/src/rum.ts
index 65867075e0..678c87a7d2 100644
--- a/packages/rum/src/rum.ts
+++ b/packages/rum/src/rum.ts
@@ -3,6 +3,7 @@ import {
   Configuration,
   Context,
   ContextValue,
+  deepMerge,
   ErrorContext,
   ErrorMessage,
   getTimestamp,
@@ -18,7 +19,6 @@ import {
   ResourceKind,
   withSnakeCaseKeys,
 } from '@datadog/browser-core'
-import lodashMerge from 'lodash.merge'
 
 import { LifeCycle, LifeCycleEventType } from './lifeCycle'
 import { matchRequestTiming } from './matchRequestTiming'
@@ -153,17 +153,18 @@ export function startRum(
 ): Omit<RumGlobal, 'init'> {
   let globalContext: Context = {}
 
-  internalMonitoring.setExternalContextProvider(() =>
-    lodashMerge(
-      {
-        application_id: applicationId,
-        session_id: viewContext.sessionId,
-        view: {
-          id: viewContext.id,
+  internalMonitoring.setExternalContextProvider(
+    () =>
+      deepMerge(
+        {
+          application_id: applicationId,
+          session_id: viewContext.sessionId,
+          view: {
+            id: viewContext.id,
+          },
         },
-      },
-      globalContext
-    )
+        globalContext
+      ) as Context
   )
 
   const batch = startRumBatch(
@@ -233,7 +234,7 @@ function startRumBatch(
     configuration.batchBytesLimit,
     configuration.maxMessageSize,
     configuration.flushTimeout,
-    () => lodashMerge(withSnakeCaseKeys(rumContextProvider()), globalContextProvider()),
+    () => deepMerge(withSnakeCaseKeys(rumContextProvider()), globalContextProvider()) as Context,
     beforeUnloadCallback
   )
   return {
diff --git a/test/app/yarn.lock b/test/app/yarn.lock
index 3ca5ca099d..46db289411 100644
--- a/test/app/yarn.lock
+++ b/test/app/yarn.lock
@@ -2,27 +2,21 @@
 # yarn lockfile v1
 
 
-"@datadog/browser-core@1.8.3", "@datadog/browser-core@file:../../packages/core":
-  version "1.8.3"
+"@datadog/browser-core@1.11.4", "@datadog/browser-core@file:../../packages/core":
+  version "1.11.4"
   dependencies:
-    lodash.assign "4.2.0"
-    lodash.merge "4.6.2"
     tslib "1.10.0"
 
 "@datadog/browser-logs@file:../../packages/logs":
-  version "1.8.3"
+  version "1.11.4"
   dependencies:
-    "@datadog/browser-core" "1.8.3"
-    lodash.assign "4.2.0"
-    lodash.merge "4.6.2"
+    "@datadog/browser-core" "1.11.4"
     tslib "1.10.0"
 
 "@datadog/browser-rum@file:../../packages/rum":
-  version "1.8.3"
+  version "1.11.4"
   dependencies:
-    "@datadog/browser-core" "1.8.3"
-    lodash.assign "4.2.0"
-    lodash.merge "4.6.2"
+    "@datadog/browser-core" "1.11.4"
     tslib "1.10.0"
 
 "@webassemblyjs/ast@1.8.5":
@@ -1280,16 +1274,6 @@ locate-path@^3.0.0:
     p-locate "^3.0.0"
     path-exists "^3.0.0"
 
-lodash.assign@4.2.0:
-  version "4.2.0"
-  resolved "https://registry.yarnpkg.com/lodash.assign/-/lodash.assign-4.2.0.tgz#0d99f3ccd7a6d261d19bdaeb9245005d285808e7"
-  integrity sha1-DZnzzNem0mHRm9rrkkUAXShYCOc=
-
-lodash.merge@4.6.2:
-  version "4.6.2"
-  resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-4.6.2.tgz#558aa53b43b661e1925a0afdfa36a9a1085fe57a"
-  integrity sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==
-
 lru-cache@^5.1.1:
   version "5.1.1"
   resolved "https://registry.yarnpkg.com/lru-cache/-/lru-cache-5.1.1.tgz#1da27e6710271947695daf6848e847f01d84b920"
diff --git a/yarn.lock b/yarn.lock
index f819d4a48b..dc41eff176 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1080,25 +1080,6 @@
   dependencies:
     "@types/node" "*"
 
-"@types/lodash.assign@4.2.6":
-  version "4.2.6"
-  resolved "https://registry.yarnpkg.com/@types/lodash.assign/-/lodash.assign-4.2.6.tgz#e5cc225446c706907893263d5938c6571ad28551"
-  integrity sha512-SaReADQZqf99FUWZ/gHICOAhLfBvaUmVb9y8xCw7o5WDuqDG0YfN1a+by29eipPcV4FITfPbQMJQiOGAeOb4fw==
-  dependencies:
-    "@types/lodash" "*"
-
-"@types/lodash.merge@4.6.6":
-  version "4.6.6"
-  resolved "https://registry.yarnpkg.com/@types/lodash.merge/-/lodash.merge-4.6.6.tgz#b84b403c1d31bc42d51772d1cd5557fa008cd3d6"
-  integrity sha512-IB90krzMf7YpfgP3u/EvZEdXVvm4e3gJbUvh5ieuI+o+XqiNEt6fCzqNRaiLlPVScLI59RxIGZMQ3+Ko/DJ8vQ==
-  dependencies:
-    "@types/lodash" "*"
-
-"@types/lodash@*":
-  version "4.14.136"
-  resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.136.tgz#413e85089046b865d960c9ff1d400e04c31ab60f"
-  integrity sha512-0GJhzBdvsW2RUccNHOBkabI8HZVdOXmXbXhuKlDEd5Vv12P7oAVGfomGp3Ne21o5D/qu1WmthlNKFaoZJJeErA==
-
 "@types/mime-types@^2.1.0":
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/@types/mime-types/-/mime-types-2.1.0.tgz#9ca52cda363f699c69466c2a6ccdaad913ea7a73"
@@ -6122,7 +6103,7 @@ lodash._root@^3.0.0:
   resolved "https://registry.yarnpkg.com/lodash._root/-/lodash._root-3.0.1.tgz#fba1c4524c19ee9a5f8136b4609f017cf4ded692"
   integrity sha1-+6HEUkwZ7ppfgTa0YJ8BfPTe1pI=
 
-lodash.assign@4.2.0, lodash.assign@^4.2.0:
+lodash.assign@^4.2.0:
   version "4.2.0"
   resolved "https://registry.yarnpkg.com/lodash.assign/-/lodash.assign-4.2.0.tgz#0d99f3ccd7a6d261d19bdaeb9245005d285808e7"
   integrity sha1-DZnzzNem0mHRm9rrkkUAXShYCOc=
@@ -6203,7 +6184,7 @@ lodash.keys@^3.0.0:
     lodash.isarguments "^3.0.0"
     lodash.isarray "^3.0.0"
 
-lodash.merge@4.6.2, lodash.merge@^4.6.1:
+lodash.merge@^4.6.1:
   version "4.6.2"
   resolved "https://registry.yarnpkg.com/lodash.merge/-/lodash.merge-4.6.2.tgz#558aa53b43b661e1925a0afdfa36a9a1085fe57a"
   integrity sha512-0KpjqXRVvrYyCsX1swR/XTK0va6VQkQM6MNo7PqW77ByjAhoARA8EfrP1N4+KlKj8YS0ZUCtRT/YUuhyYDujIQ==