diff --git a/packages/core/package.json b/packages/core/package.json
index f41f42b9..5f18ac9d 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -52,7 +52,6 @@
     "typescript": "^5.9.3"
   },
   "dependencies": {
-    "@datadog/js-core": "0.0.3",
     "spark-md5": "^3.0.2"
   }
 }
diff --git a/packages/core/src/configuration/configuration.ts b/packages/core/src/configuration/configuration.ts
index 47fb6a81..0771f1e8 100644
--- a/packages/core/src/configuration/configuration.ts
+++ b/packages/core/src/configuration/configuration.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContext, FlagValueType, JsonValue, ResolutionReason } from '@openfeature/core'
+import type { TimeStamp } from '../time'
 
 /**
  * Internal flags configuration for DatadogProvider.
diff --git a/packages/core/src/configuration/exposureEvent.types.ts b/packages/core/src/configuration/exposureEvent.types.ts
index 85afbc54..500c9843 100644
--- a/packages/core/src/configuration/exposureEvent.types.ts
+++ b/packages/core/src/configuration/exposureEvent.types.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContext } from '@openfeature/core'
+import type { TimeStamp } from '../time'
 
 export interface ExposureEvent {
   allocation: {
diff --git a/packages/core/src/configuration/flagEvaluationAggregator.ts b/packages/core/src/configuration/flagEvaluationAggregator.ts
index 7a65ccd8..fba28568 100644
--- a/packages/core/src/configuration/flagEvaluationAggregator.ts
+++ b/packages/core/src/configuration/flagEvaluationAggregator.ts
@@ -1,7 +1,6 @@
-import type { TimeStamp } from '@datadog/js-core/time'
-import { timeStampNow } from '@datadog/js-core/time'
 import type { EvaluationContext, EvaluationContextValue, EvaluationDetails, FlagValue } from '@openfeature/core'
 import { getMD5Hash } from '../obfuscation'
+import { type TimeStamp, timeStampNow } from '../time'
 import { createFlagEvaluationEvent } from './flagEvaluationEvent'
 import type { FlagEvaluationEvent } from './flagEvaluationEvent.types'
 
diff --git a/packages/core/src/configuration/flagEvaluationEvent.ts b/packages/core/src/configuration/flagEvaluationEvent.ts
index 916ed8b3..1ef1dedd 100644
--- a/packages/core/src/configuration/flagEvaluationEvent.ts
+++ b/packages/core/src/configuration/flagEvaluationEvent.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContextValue } from '@openfeature/core'
+import type { TimeStamp } from '../time'
 import type { FlagEvaluationEvent } from './flagEvaluationEvent.types'
 
 interface FlagEvaluationAggregationData {
diff --git a/packages/core/src/configuration/flagEvaluationEvent.types.ts b/packages/core/src/configuration/flagEvaluationEvent.types.ts
index 863fd457..cfbdfb23 100644
--- a/packages/core/src/configuration/flagEvaluationEvent.types.ts
+++ b/packages/core/src/configuration/flagEvaluationEvent.types.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContextValue } from '@openfeature/core'
+import type { TimeStamp } from '../time'
 
 export interface FlagEvaluationEvent {
   flag: {
diff --git a/packages/core/src/configuration/wire.ts b/packages/core/src/configuration/wire.ts
index 615f8922..4bc2c1b3 100644
--- a/packages/core/src/configuration/wire.ts
+++ b/packages/core/src/configuration/wire.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContext } from '@openfeature/core'
+import type { TimeStamp } from '../time'
 import type { FlagsConfiguration } from './configuration'
 
 type ConfigurationWire = {
diff --git a/packages/core/src/evaluation/evaluateForSubject.ts b/packages/core/src/evaluation/evaluateForSubject.ts
index 0fbd66b6..6e4dc200 100644
--- a/packages/core/src/evaluation/evaluateForSubject.ts
+++ b/packages/core/src/evaluation/evaluateForSubject.ts
@@ -1,7 +1,6 @@
-import type { TimeStamp } from '@datadog/js-core/time'
-import { timeStampNow } from '@datadog/js-core/time'
 import type { ErrorCode, EvaluationContext, FlagValueType, Logger, ResolutionDetails } from '@openfeature/core'
 import type { FlagTypeToValue, PrecomputedFlagMetadata } from '../configuration'
+import { type TimeStamp, timeStampNow } from '../time'
 import { TargetingKeyMissingError } from './errors'
 import { createEvaluationTimestampMetadata } from './evaluationMetadata'
 import { matchesShard } from './matchesShard'
diff --git a/packages/core/src/evaluation/evaluation.ts b/packages/core/src/evaluation/evaluation.ts
index ff8e8be9..5ddd83ef 100644
--- a/packages/core/src/evaluation/evaluation.ts
+++ b/packages/core/src/evaluation/evaluation.ts
@@ -1,6 +1,6 @@
-import { timeStampNow } from '@datadog/js-core/time'
 import type { ErrorCode, EvaluationContext, FlagValueType, Logger, ResolutionDetails } from '@openfeature/core'
 import type { FlagTypeToValue } from '../configuration'
+import { timeStampNow } from '../time'
 import { TargetingKeyMissingError } from './errors'
 import { evaluateForSubject } from './evaluateForSubject'
 import { createEvaluationTimestampMetadata } from './evaluationMetadata'
diff --git a/packages/core/src/evaluation/evaluationMetadata.ts b/packages/core/src/evaluation/evaluationMetadata.ts
index b42a923e..d0be97d7 100644
--- a/packages/core/src/evaluation/evaluationMetadata.ts
+++ b/packages/core/src/evaluation/evaluationMetadata.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { PrecomputedFlagMetadata } from '../configuration'
+import type { TimeStamp } from '../time'
 
 export function createEvaluationTimestampMetadata(evaluationTimestampMs: TimeStamp): PrecomputedFlagMetadata {
   return { __dd_eval_timestamp_ms: evaluationTimestampMs } as PrecomputedFlagMetadata
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 56deefff..018d0574 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -2,6 +2,7 @@ export * from './cache'
 export * from './configuration'
 export * from './evaluation'
 export * from './obfuscation'
+export * from './time'
 
 // Build environment placeholder for testing
 const _SDK_VERSION = __BUILD_ENV__SDK_VERSION__
diff --git a/packages/core/src/time.ts b/packages/core/src/time.ts
new file mode 100644
index 00000000..d923b141
--- /dev/null
+++ b/packages/core/src/time.ts
@@ -0,0 +1,6 @@
+/** Unix epoch timestamp in milliseconds. */
+export type TimeStamp = number & { t: 'Epoch time' }
+
+export function timeStampNow(): TimeStamp {
+  return new Date().getTime() as TimeStamp
+}
diff --git a/packages/core/test/configuration/flagEvaluationEvent.spec.ts b/packages/core/test/configuration/flagEvaluationEvent.spec.ts
index 4cde63e7..08d42f38 100644
--- a/packages/core/test/configuration/flagEvaluationEvent.spec.ts
+++ b/packages/core/test/configuration/flagEvaluationEvent.spec.ts
@@ -1,5 +1,5 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import { createFlagEvaluationEvent } from '../../src/configuration/flagEvaluationEvent'
+import type { TimeStamp } from '../../src/time'
 
 describe('createFlagEvaluationEvent', () => {
   it('should include targeting_key when it is a non-empty string', () => {
diff --git a/packages/core/test/evaluation/evaluateForSubject.spec.ts b/packages/core/test/evaluation/evaluateForSubject.spec.ts
index 919ed5a6..6ddc9d76 100644
--- a/packages/core/test/evaluation/evaluateForSubject.spec.ts
+++ b/packages/core/test/evaluation/evaluateForSubject.spec.ts
@@ -1,6 +1,6 @@
-import type { TimeStamp } from '@datadog/js-core/time'
 import type { EvaluationContext, Logger } from '@openfeature/core'
 import { evaluateForSubject, type Flag } from '../../src/evaluation'
+import type { TimeStamp } from '../../src/time'
 
 describe('evaluateForSubject', () => {
   let logger: Logger
diff --git a/packages/node-server/package.json b/packages/node-server/package.json
index 8d9436fd..ffc0847c 100644
--- a/packages/node-server/package.json
+++ b/packages/node-server/package.json
@@ -36,8 +36,7 @@
     "typecheck": "tsc --noEmit"
   },
   "dependencies": {
-    "@datadog/flagging-core": "2.0.1",
-    "@datadog/js-core": "0.0.3"
+    "@datadog/flagging-core": "2.0.1"
   },
   "peerDependencies": {
     "@openfeature/server-sdk": ">=1.15.1"
diff --git a/packages/node-server/src/provider.ts b/packages/node-server/src/provider.ts
index 886d3f5d..380fee59 100644
--- a/packages/node-server/src/provider.ts
+++ b/packages/node-server/src/provider.ts
@@ -4,8 +4,8 @@ import {
   createExposureEvent,
   type ExposureEvent,
   LRUInMemoryAssignmentCache,
+  timeStampNow,
 } from '@datadog/flagging-core'
-import { timeStampNow } from '@datadog/js-core/time'
 import type { EvaluationContext } from '@openfeature/core'
 import type {
   EvaluationDetails,
diff --git a/scripts/assert-node-package-purity.js b/scripts/assert-node-package-purity.js
new file mode 100644
index 00000000..e1df8b60
--- /dev/null
+++ b/scripts/assert-node-package-purity.js
@@ -0,0 +1,65 @@
+'use strict'
+
+const fs = require('node:fs')
+const path = require('node:path')
+
+const forbiddenPackageNames = [/^@datadog\/browser-/, /^@datadog\/js-core$/, /^@datadog\/openfeature-browser$/]
+const browserSdkRepository = /github\.com[/:]DataDog\/browser-sdk(?:\.git)?$/i
+
+const found = new Set()
+const visited = new Set()
+
+function inspectPackage(packageDirectory) {
+  let realDirectory
+  try {
+    realDirectory = fs.realpathSync(packageDirectory)
+  } catch {
+    return
+  }
+
+  if (visited.has(realDirectory)) return
+  visited.add(realDirectory)
+
+  const manifestPath = path.join(realDirectory, 'package.json')
+  if (fs.existsSync(manifestPath)) {
+    const manifest = JSON.parse(fs.readFileSync(manifestPath, 'utf8'))
+    const repository = typeof manifest.repository === 'string' ? manifest.repository : manifest.repository?.url
+    const isBrowserSdkDependency =
+      forbiddenPackageNames.some((pattern) => pattern.test(manifest.name)) ||
+      browserSdkRepository.test(repository ?? '')
+    if (isBrowserSdkDependency) {
+      found.add(manifest.name)
+    }
+  }
+
+  inspectNodeModules(path.join(realDirectory, 'node_modules'))
+}
+
+function inspectNodeModules(nodeModulesDirectory) {
+  if (!fs.existsSync(nodeModulesDirectory)) return
+
+  for (const entry of fs.readdirSync(nodeModulesDirectory, { withFileTypes: true })) {
+    if (entry.name.startsWith('.')) continue
+
+    const entryPath = path.join(nodeModulesDirectory, entry.name)
+    if (entry.name.startsWith('@')) {
+      for (const scopedEntry of fs.readdirSync(entryPath, { withFileTypes: true })) {
+        if (scopedEntry.isDirectory() || scopedEntry.isSymbolicLink()) {
+          inspectPackage(path.join(entryPath, scopedEntry.name))
+        }
+      }
+    } else if (entry.isDirectory() || entry.isSymbolicLink()) {
+      inspectPackage(entryPath)
+    }
+  }
+}
+
+inspectNodeModules(path.resolve(process.argv[2] ?? 'node_modules'))
+
+if (found.size > 0) {
+  console.error('ERROR: Node packages must not install browser SDK dependencies')
+  for (const packageName of [...found].sort()) console.error(packageName)
+  process.exit(1)
+}
+
+console.log('Verified Node packages do not install browser SDK dependencies')
diff --git a/scripts/test-node-package-install.sh b/scripts/test-node-package-install.sh
index a2a97908..2e2e700f 100755
--- a/scripts/test-node-package-install.sh
+++ b/scripts/test-node-package-install.sh
@@ -125,6 +125,8 @@ if [ "$WITH_OPENFEATURE" = true ]; then
   fi
 fi
 
+node "$REPO_ROOT/scripts/assert-node-package-purity.js" node_modules
+
 # Run tests
 echo ""
 echo "Running tests..."
diff --git a/yarn.lock b/yarn.lock
index 6c4a57ed..ec89a87f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -663,7 +663,6 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@datadog/flagging-core@workspace:packages/core"
   dependencies:
-    "@datadog/js-core": "npm:0.0.3"
     "@openfeature/core": "npm:^1.9.2"
     "@types/jest": "npm:^30.0.0"
     "@types/node": "npm:^18.0.0"
@@ -741,7 +740,6 @@ __metadata:
   resolution: "@datadog/openfeature-node-server@workspace:packages/node-server"
   dependencies:
     "@datadog/flagging-core": "npm:2.0.1"
-    "@datadog/js-core": "npm:0.0.3"
     "@openfeature/core": "npm:1.9.2"
     "@openfeature/server-sdk": "npm:1.20.2"
     "@types/jest": "npm:^30.0.0"