diff --git a/.storybook/vite.config.ts b/.storybook/vite.config.ts
index f49622a49f..f6c6be4a0b 100644
--- a/.storybook/vite.config.ts
+++ b/.storybook/vite.config.ts
@@ -46,6 +46,9 @@ export default defineConfig({
       apiClient: fileURLToPath(
         new URL('../redisinsight/api-client', import.meta.url),
       ),
+      'riShared': fileURLToPath(
+        new URL('../redisinsight/api/src/ri-shared', import.meta.url),
+      ),
     },
   },
   server: {
diff --git a/jest.config.cjs b/jest.config.cjs
index c069331638..0b287b5c21 100644
--- a/jest.config.cjs
+++ b/jest.config.cjs
@@ -16,6 +16,7 @@ module.exports = {
     'uiSrc/(.*)': '<rootDir>/redisinsight/ui/src/$1',
     '^apiClient$': '<rootDir>/redisinsight/api-client',
     'apiClient/(.*)': '<rootDir>/redisinsight/api-client/$1',
+    '^riShared/(.*)$': '<rootDir>/redisinsight/api/src/ri-shared/$1',
     '@redislabsdev/redis-ui-components': '@redis-ui/components',
     '@redislabsdev/redis-ui-styles': '@redis-ui/styles',
     '@redislabsdev/redis-ui-icons': '@redis-ui/icons',
diff --git a/redisinsight/api/src/common/utils/index.ts b/redisinsight/api/src/common/utils/index.ts
index 58ade32415..148208f474 100644
--- a/redisinsight/api/src/common/utils/index.ts
+++ b/redisinsight/api/src/common/utils/index.ts
@@ -1,4 +1,4 @@
-export * from './array-index.helper';
+export * from '../../ri-shared/utils/array-index';
 export * from './certificate-import.util';
 export * from './errors.util';
 export * from './merge.util';
diff --git a/redisinsight/api/src/common/validators/array-index.validator.ts b/redisinsight/api/src/common/validators/array-index.validator.ts
index eee9404cc8..d97a422553 100644
--- a/redisinsight/api/src/common/validators/array-index.validator.ts
+++ b/redisinsight/api/src/common/validators/array-index.validator.ts
@@ -3,10 +3,7 @@ import {
   ValidatorConstraint,
   ValidatorConstraintInterface,
 } from 'class-validator';
-import {
-  ARRAY_INDEX_MAX,
-  parseArrayIndex,
-} from 'src/common/utils/array-index.helper';
+import { ARRAY_INDEX_MAX, parseArrayIndex } from 'src/common/utils';
 
 @ValidatorConstraint({ name: 'ArrayIndexValidator', async: false })
 export class ArrayIndexValidator implements ValidatorConstraintInterface {
diff --git a/redisinsight/api/src/ri-shared/README.md b/redisinsight/api/src/ri-shared/README.md
new file mode 100644
index 0000000000..a273027fb9
--- /dev/null
+++ b/redisinsight/api/src/ri-shared/README.md
@@ -0,0 +1,33 @@
+# ri-shared — code shared across the RedisInsight apps (API + UI)
+
+Modules here are consumed by **both** the API (relative imports, e.g.
+`src/ri-shared/utils/array-index`) and the UI (the `riShared/*` path alias). They live
+inside `api/src` because the api's production build (`nest build` → `node dist/src/main`)
+compiles with `api/src` as the tsc rootDir — sources outside it restructure `dist/` and
+break the packaged app. The UI/Storybook/jest aliases simply point into this folder, so
+shared code ships with zero extra packaging surface (desktop bundles it like any api file).
+
+## What belongs here
+
+- Cross-boundary **contracts**: value formats both sides must agree on (e.g. the
+  BigInt-as-string array index format), stable message formats, shared constants.
+- Small **dependency-free** utilities needed verbatim on both sides.
+
+## Rules
+
+- **No imports** from Nest, React, ioredis, lodash or anything else — dependency-free
+  TypeScript only (the UI and API have separate node_modules; nothing here may assume
+  either).
+- **es2019-compatible**: the api compiles this folder with `target: es2019` — no BigInt
+  literals (`1n` is TS2737; use `BigInt('...')`), no newer syntax.
+- API code style (semicolons) — this folder is linted by `yarn lint:api`.
+- Tests live next to the module (`*.spec.ts`, runs under the api jest config) and define
+  the shared behavior once — UI consumers exercise it through their barrel imports.
+
+## Alias wiring (when adding the alias to a new consumer)
+
+`redisinsight/ui/tsconfig.json` + `redisinsight/ui/vite.config.mjs` +
+`redisinsight/ui/src/packages/vite.config.mjs` (Workbench plugin builds reach
+the `uiSrc/utils` barrel) + `jest.config.cjs` (root, UI tests) +
+`.storybook/vite.config.ts` + `redisinsight/desktop/tsconfig.json` all map
+`riShared/*` → `redisinsight/api/src/ri-shared/*`.
diff --git a/redisinsight/api/src/common/utils/array-index.helper.spec.ts b/redisinsight/api/src/ri-shared/utils/array-index.spec.ts
similarity index 96%
rename from redisinsight/api/src/common/utils/array-index.helper.spec.ts
rename to redisinsight/api/src/ri-shared/utils/array-index.spec.ts
index 88b4e322c4..1543f305d2 100644
--- a/redisinsight/api/src/common/utils/array-index.helper.spec.ts
+++ b/redisinsight/api/src/ri-shared/utils/array-index.spec.ts
@@ -2,9 +2,9 @@ import {
   ARRAY_INDEX_MAX,
   isValidArrayIndex,
   parseArrayIndex,
-} from 'src/common/utils';
+} from './array-index';
 
-describe('array-index.helper', () => {
+describe('shared array-index', () => {
   it('should expose max unsigned 64-bit value', () => {
     expect(ARRAY_INDEX_MAX).toEqual(BigInt('18446744073709551615'));
   });
diff --git a/redisinsight/api/src/common/utils/array-index.helper.ts b/redisinsight/api/src/ri-shared/utils/array-index.ts
similarity index 63%
rename from redisinsight/api/src/common/utils/array-index.helper.ts
rename to redisinsight/api/src/ri-shared/utils/array-index.ts
index f1a680d780..837b88b528 100644
--- a/redisinsight/api/src/common/utils/array-index.helper.ts
+++ b/redisinsight/api/src/ri-shared/utils/array-index.ts
@@ -1,13 +1,19 @@
 /**
  * Redis array indexes are unsigned 64-bit integers (0 … 2^64−1) and exceed
  * Number.MAX_SAFE_INTEGER, so they travel as numeric strings end-to-end —
- * never parseInt/Number, no JS-side arithmetic on indexes.
+ * never parseInt/Number, no JS-side arithmetic on indexes (the UI's Redux
+ * store keeps them as strings too).
  *
- * Mirrored in redisinsight/ui/src/utils/arrayIndex.ts — keep semantics and
- * tests in sync.
+ * Shared by the UI and the API (see src/ri-shared/README.md): the API
+ * imports it relatively (it lives in the api compile root, so `nest build`
+ * emits it into dist like any other api source), the UI through the
+ * `riShared/*` alias (wired in redisinsight/ui/vite.config.mjs,
+ * redisinsight/ui/tsconfig.json, .storybook/vite.config.ts and
+ * jest.config.cjs). It must stay dependency-free and es2019-compatible —
+ * BigInt('...') calls only, since BigInt literals are a syntax error
+ * (TS2737) under the api's es2019 target.
  */
-// 2^64 - 1; BigInt() call (not a literal) — this tsconfig targets es2019,
-// where BigInt literals are a syntax error (TS2737).
+// 2^64 - 1
 export const ARRAY_INDEX_MAX = BigInt('18446744073709551615');
 
 const ARRAY_INDEX_REGEX = /^\d+$/;
diff --git a/redisinsight/desktop/tsconfig.json b/redisinsight/desktop/tsconfig.json
index fe6781b1e5..5c0210ce73 100644
--- a/redisinsight/desktop/tsconfig.json
+++ b/redisinsight/desktop/tsconfig.json
@@ -29,7 +29,8 @@
       "apiSrc/*": ["redisinsight/api/src/*"],
       "uiSrc/*": ["redisinsight/ui/src/*"],
       "apiClient": ["redisinsight/api-client"],
-      "apiClient/*": ["redisinsight/api-client/*"]
+      "apiClient/*": ["redisinsight/api-client/*"],
+      "riShared/*": ["redisinsight/api/src/ri-shared/*"]
     }
   },
   "include": ["**/*"],
diff --git a/redisinsight/ui/src/packages/vite.config.mjs b/redisinsight/ui/src/packages/vite.config.mjs
index 0bddb6e354..2b6365110b 100644
--- a/redisinsight/ui/src/packages/vite.config.mjs
+++ b/redisinsight/ui/src/packages/vite.config.mjs
@@ -45,6 +45,9 @@ export default defineConfig({
       '@redislabsdev/redis-ui-table': '@redis-ui/table',
       uiSrc: fileURLToPath(new URL('../../src', import.meta.url)),
       apiClient: fileURLToPath(new URL('../../../api-client', import.meta.url)),
+      riShared: fileURLToPath(
+        new URL('../../../api/src/ri-shared', import.meta.url),
+      ),
     },
     dedupe: ['react', 'react-dom'],
   },
diff --git a/redisinsight/ui/src/utils/arrayIndex.ts b/redisinsight/ui/src/utils/arrayIndex.ts
deleted file mode 100644
index e027875140..0000000000
--- a/redisinsight/ui/src/utils/arrayIndex.ts
+++ /dev/null
@@ -1,44 +0,0 @@
-/**
- * Redis array indexes are unsigned 64-bit integers (0 … 2^64−1) and exceed
- * Number.MAX_SAFE_INTEGER, so they stay numeric strings end-to-end —
- * never parseInt/Number, no JS-side arithmetic on indexes; Redux stores
- * them as strings.
- *
- * Mirrored in redisinsight/api/src/common/utils/array-index.helper.ts —
- * keep semantics and tests in sync.
- */
-// 2^64 - 1; BigInt() call form (not a literal) for parity with the API
-// mirror, whose tsconfig targets es2019 (where BigInt literals are TS2737).
-export const ARRAY_INDEX_MAX = BigInt('18446744073709551615')
-
-const ARRAY_INDEX_REGEX = /^\d+$/
-
-// Max u64 is 20 digits; longer all-digit inputs can't be valid and a length
-// guard keeps BigInt() from parsing arbitrarily large request payloads.
-const ARRAY_INDEX_MAX_LENGTH = 20
-
-/**
- * Returns the canonical decimal string for a valid index ("007" → "7"),
- * or null for anything else (empty or whitespace-only, negative,
- * fractional, exponent, hex, > 2^64−1, non-string input).
- */
-export const parseArrayIndex = (input: unknown): string | null => {
-  if (typeof input !== 'string') {
-    return null
-  }
-
-  const value = input.trim()
-  if (!ARRAY_INDEX_REGEX.test(value)) {
-    return null
-  }
-
-  if (value.length > ARRAY_INDEX_MAX_LENGTH) {
-    return null
-  }
-
-  const index = BigInt(value)
-  return index > ARRAY_INDEX_MAX ? null : index.toString()
-}
-
-export const isValidArrayIndex = (input: unknown): boolean =>
-  parseArrayIndex(input) !== null
diff --git a/redisinsight/ui/src/utils/index.ts b/redisinsight/ui/src/utils/index.ts
index 79ddcfbdc6..d4ff6c0351 100644
--- a/redisinsight/ui/src/utils/index.ts
+++ b/redisinsight/ui/src/utils/index.ts
@@ -4,7 +4,7 @@ import RouterWithSubRoutes from './routerWithSubRoutes'
 
 export * from './common'
 export * from './validations'
-export * from './arrayIndex'
+export * from 'riShared/utils/array-index'
 export * from './statuses'
 export * from './instance'
 export * from './apiResponse'
diff --git a/redisinsight/ui/src/utils/tests/arrayIndex.spec.ts b/redisinsight/ui/src/utils/tests/arrayIndex.spec.ts
deleted file mode 100644
index 757f6bed85..0000000000
--- a/redisinsight/ui/src/utils/tests/arrayIndex.spec.ts
+++ /dev/null
@@ -1,53 +0,0 @@
-import {
-  ARRAY_INDEX_MAX,
-  isValidArrayIndex,
-  parseArrayIndex,
-} from 'uiSrc/utils'
-
-describe('arrayIndex', () => {
-  it('should expose max unsigned 64-bit value', () => {
-    expect(ARRAY_INDEX_MAX).toEqual(BigInt('18446744073709551615'))
-  })
-
-  describe('parseArrayIndex', () => {
-    it.each([
-      { input: '0', expected: '0' },
-      { input: '7', expected: '7' },
-      { input: '007', expected: '7' }, // leading zeros normalized
-      { input: ' 42 ', expected: '42' }, // outer whitespace trimmed
-      { input: '18446744073709551615', expected: '18446744073709551615' }, // max u64
-      { input: '18446744073709551616', expected: null }, // max + 1
-      { input: '184467440737095516150', expected: null }, // 21 digits — length guard
-      { input: '00000000000000000000042', expected: null }, // >20 chars — guard trumps normalization
-      { input: '-1', expected: null },
-      { input: '1.5', expected: null },
-      { input: '1e3', expected: null },
-      { input: '0x10', expected: null },
-      { input: 'abc', expected: null },
-      { input: '1 2', expected: null }, // internal whitespace
-      { input: '', expected: null },
-      { input: '   ', expected: null },
-    ])('should return $expected for $input', ({ input, expected }) => {
-      expect(parseArrayIndex(input)).toEqual(expected)
-    })
-
-    it.each([null, undefined, 7, BigInt(7), {}])(
-      'should return null for non-string %p',
-      (input) => {
-        expect(parseArrayIndex(input)).toEqual(null)
-      },
-    )
-  })
-
-  describe('isValidArrayIndex', () => {
-    it('should return true for a valid index', () => {
-      expect(isValidArrayIndex('123')).toEqual(true)
-    })
-    it('should return false for an invalid index', () => {
-      expect(isValidArrayIndex('-1')).toEqual(false)
-    })
-    it('should return false for non-string input', () => {
-      expect(isValidArrayIndex(42)).toEqual(false)
-    })
-  })
-})
diff --git a/redisinsight/ui/tsconfig.json b/redisinsight/ui/tsconfig.json
index bec43b37f5..bf750275ed 100644
--- a/redisinsight/ui/tsconfig.json
+++ b/redisinsight/ui/tsconfig.json
@@ -29,7 +29,8 @@
     "paths": {
       "uiSrc/*": ["src/*"],
       "apiClient": ["../api-client"],
-      "apiClient/*": ["../api-client/*"]
+      "apiClient/*": ["../api-client/*"],
+      "riShared/*": ["../api/src/ri-shared/*"]
     }
   },
   "include": [
diff --git a/redisinsight/ui/vite.config.mjs b/redisinsight/ui/vite.config.mjs
index 03319c2e61..cf10d4f149 100644
--- a/redisinsight/ui/vite.config.mjs
+++ b/redisinsight/ui/vite.config.mjs
@@ -83,6 +83,7 @@ export default defineConfig({
       '@redislabsdev/redis-ui-table': '@redis-ui/table',
       uiSrc: fileURLToPath(new URL('./src', import.meta.url)),
       apiClient: fileURLToPath(new URL('../api-client', import.meta.url)),
+      'riShared': fileURLToPath(new URL('../api/src/ri-shared', import.meta.url)),
     },
   },
   server: {