diff --git a/examples/partial_results_example/public/plugin.tsx b/examples/partial_results_example/public/plugin.tsx
index aa209a87918e7..9599a0d6f590c 100755
--- a/examples/partial_results_example/public/plugin.tsx
+++ b/examples/partial_results_example/public/plugin.tsx
@@ -7,7 +7,8 @@
  */
 import React from 'react';
 import ReactDOM from 'react-dom';
-import type { ExpressionsService, ExpressionsServiceSetup } from 'src/plugins/expressions';
+import type { ExpressionsServiceSetup } from 'src/plugins/expressions';
+import { ExpressionsServiceFork } from 'src/plugins/expressions/common/service/expressions_fork';
 import { AppMountParameters, AppNavLinkStatus, CoreSetup, Plugin } from '../../../src/core/public';
 import type { DeveloperExamplesSetup } from '../../developer_examples/public';
 import { App, ExpressionsContext } from './app';
@@ -19,13 +20,15 @@ interface SetupDeps {
 }
 
 export class PartialResultsExamplePlugin implements Plugin<void, void, SetupDeps> {
-  private expressions?: ExpressionsService;
+  private expressions?: ExpressionsServiceFork;
 
   setup({ application }: CoreSetup, { expressions, developerExamples }: SetupDeps) {
-    this.expressions = expressions.fork();
-    this.expressions.registerFunction(countEvent);
-    this.expressions.registerFunction(getEvents);
-    this.expressions.registerFunction(pluck);
+    this.expressions = expressions.fork('test');
+    const expressionsSetup = this.expressions.setup();
+    expressionsSetup.registerFunction(countEvent);
+    expressionsSetup.registerFunction(getEvents);
+    expressionsSetup.registerFunction(pluck);
+    const expressionsStart = this.expressions.start();
 
     application.register({
       id: 'partialResultsExample',
@@ -33,7 +36,7 @@ export class PartialResultsExamplePlugin implements Plugin<void, void, SetupDeps
       navLinkStatus: AppNavLinkStatus.hidden,
       mount: async ({ element }: AppMountParameters) => {
         ReactDOM.render(
-          <ExpressionsContext.Provider value={this.expressions}>
+          <ExpressionsContext.Provider value={expressionsStart}>
             <App />
           </ExpressionsContext.Provider>,
           element
diff --git a/src/plugins/expressions/common/execution/execution.ts b/src/plugins/expressions/common/execution/execution.ts
index 7cc7fa771d8c8..d3e2324b276a2 100644
--- a/src/plugins/expressions/common/execution/execution.ts
+++ b/src/plugins/expressions/common/execution/execution.ts
@@ -300,7 +300,11 @@ export class Execution<
       ...(chainArr.map((link) =>
         switchMap((currentInput) => {
           const { function: fnName, arguments: fnArgs } = link;
-          const fn = getByAlias(this.state.get().functions, fnName);
+          const fn = getByAlias(
+            this.state.get().functions,
+            fnName,
+            this.execution.params.namespace
+          );
 
           if (!fn) {
             throw createError({
diff --git a/src/plugins/expressions/common/executor/executor.ts b/src/plugins/expressions/common/executor/executor.ts
index 722083e1c739a..e9398f1d17c58 100644
--- a/src/plugins/expressions/common/executor/executor.ts
+++ b/src/plugins/expressions/common/executor/executor.ts
@@ -20,7 +20,7 @@ import { ExpressionType } from '../expression_types/expression_type';
 import { AnyExpressionTypeDefinition } from '../expression_types/types';
 import { ExpressionAstExpression, ExpressionAstFunction } from '../ast';
 import { ExpressionValueError, typeSpecs } from '../expression_types/specs';
-import { getByAlias } from '../util';
+import { ALL_NAMESPACES, getByAlias } from '../util';
 import { SavedObjectReference } from '../../../../core/types';
 import {
   MigrateFunctionsObject,
@@ -146,15 +146,17 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
     this.container.transitions.addFunction(fn);
   }
 
-  public getFunction(name: string): ExpressionFunction | undefined {
-    return this.container.get().functions[name] ?? this.parent?.getFunction(name);
+  public getFunction(name: string, namespace?: string): ExpressionFunction | undefined {
+    const fn = this.container.get().functions[name];
+    if (!fn?.namespace || fn.namespace === namespace) return fn;
   }
 
-  public getFunctions(): Record<string, ExpressionFunction> {
-    return {
-      ...(this.parent?.getFunctions() ?? {}),
-      ...this.container.get().functions,
-    };
+  public getFunctions(namespace?: string): Record<string, ExpressionFunction> {
+    const fns = Object.entries(this.container.get().functions);
+    const filtered = fns.filter(
+      ([key, value]) => !value.namespace || value.namespace === namespace
+    );
+    return Object.fromEntries(filtered);
   }
 
   public registerType(
@@ -222,9 +224,10 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
     ast: ExpressionAstExpression,
     action: (fn: ExpressionFunction, link: ExpressionAstFunction) => void
   ) {
+    const functions = this.container.get().functions;
     for (const link of ast.chain) {
       const { function: fnName, arguments: fnArgs } = link;
-      const fn = getByAlias(this.getFunctions(), fnName);
+      const fn = getByAlias(functions, fnName, ALL_NAMESPACES);
 
       if (fn) {
         // if any of arguments are expressions we should migrate those first
@@ -249,12 +252,13 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
     ) => ExpressionAstFunction | ExpressionAstExpression
   ): ExpressionAstExpression {
     let additionalFunctions = 0;
+    const functions = this.container.get().functions;
     return (
       ast.chain.reduce<ExpressionAstExpression>(
         (newAst: ExpressionAstExpression, funcAst: ExpressionAstFunction, index: number) => {
           const realIndex = index + additionalFunctions;
           const { function: fnName, arguments: fnArgs } = funcAst;
-          const fn = getByAlias(this.getFunctions(), fnName);
+          const fn = getByAlias(functions, fnName, ALL_NAMESPACES);
           if (!fn) {
             return newAst;
           }
@@ -331,7 +335,7 @@ export class Executor<Context extends Record<string, unknown> = Record<string, u
 
   public getAllMigrations() {
     const uniqueVersions = new Set(
-      Object.values(this.getFunctions())
+      Object.values(this.container.get().functions)
         .map((fn) => Object.keys(fn.migrations))
         .flat(1)
     );
diff --git a/src/plugins/expressions/common/expression_functions/expression_function.ts b/src/plugins/expressions/common/expression_functions/expression_function.ts
index 4ae51ff018f1b..951a5aab37961 100644
--- a/src/plugins/expressions/common/expression_functions/expression_function.ts
+++ b/src/plugins/expressions/common/expression_functions/expression_function.ts
@@ -24,6 +24,8 @@ export class ExpressionFunction implements PersistableState<ExpressionAstFunctio
    */
   name: string;
 
+  namespace?: string;
+
   /**
    * Aliases that can be used instead of `name`.
    */
@@ -90,9 +92,11 @@ export class ExpressionFunction implements PersistableState<ExpressionAstFunctio
       inject,
       extract,
       migrations,
+      namespace,
     } = functionDefinition;
 
     this.name = name;
+    this.namespace = namespace;
     this.type = type;
     this.aliases = aliases || [];
     this.fn = fn as ExpressionFunction['fn'];
diff --git a/src/plugins/expressions/common/expression_functions/types.ts b/src/plugins/expressions/common/expression_functions/types.ts
index cb3677ed1668c..62107d17ab67a 100644
--- a/src/plugins/expressions/common/expression_functions/types.ts
+++ b/src/plugins/expressions/common/expression_functions/types.ts
@@ -44,6 +44,8 @@ export interface ExpressionFunctionDefinition<
    */
   disabled?: boolean;
 
+  namespace?: string;
+
   /**
    * Name of type of value this function outputs.
    */
diff --git a/src/plugins/expressions/common/expression_renderers/expression_renderer.ts b/src/plugins/expressions/common/expression_renderers/expression_renderer.ts
index 56e8f23e7ad85..9a8946dd9a0d6 100644
--- a/src/plugins/expressions/common/expression_renderers/expression_renderer.ts
+++ b/src/plugins/expressions/common/expression_renderers/expression_renderer.ts
@@ -10,6 +10,7 @@ import { ExpressionRenderDefinition } from './types';
 
 export class ExpressionRenderer<Config = unknown> {
   public readonly name: string;
+  public readonly namespace?: string;
   public readonly displayName: string;
   public readonly help: string;
   public readonly validate: () => void | Error;
@@ -17,9 +18,10 @@ export class ExpressionRenderer<Config = unknown> {
   public readonly render: ExpressionRenderDefinition<Config>['render'];
 
   constructor(config: ExpressionRenderDefinition<Config>) {
-    const { name, displayName, help, validate, reuseDomNode, render } = config;
+    const { name, displayName, help, validate, reuseDomNode, render, namespace } = config;
 
     this.name = name;
+    this.namespace = namespace;
     this.displayName = displayName || name;
     this.help = help || '';
     this.validate = validate || (() => {});
diff --git a/src/plugins/expressions/common/expression_renderers/types.ts b/src/plugins/expressions/common/expression_renderers/types.ts
index 6c889a81a1f80..1e40ba2a65fff 100644
--- a/src/plugins/expressions/common/expression_renderers/types.ts
+++ b/src/plugins/expressions/common/expression_renderers/types.ts
@@ -15,6 +15,7 @@ export interface ExpressionRenderDefinition<Config = unknown> {
    * function that is used to create the `type: render` object.
    */
   name: string;
+  namespace?: string;
 
   /**
    * A user friendly name of the renderer as will be displayed to user in UI.
diff --git a/src/plugins/expressions/common/expression_types/expression_type.ts b/src/plugins/expressions/common/expression_types/expression_type.ts
index bf8a96a4ab1e6..59afd5e94a7b8 100644
--- a/src/plugins/expressions/common/expression_types/expression_type.ts
+++ b/src/plugins/expressions/common/expression_types/expression_type.ts
@@ -12,7 +12,7 @@ import { getType } from './get_type';
 
 export class ExpressionType {
   name: string;
-
+  namespace?: string;
   /**
    * A short help text.
    */
@@ -33,9 +33,10 @@ export class ExpressionType {
   private readonly definition: AnyExpressionTypeDefinition;
 
   constructor(definition: AnyExpressionTypeDefinition) {
-    const { name, help, deserialize, serialize, validate } = definition;
+    const { name, help, deserialize, serialize, validate, namespace } = definition;
 
     this.name = name;
+    this.namespace = namespace;
     this.help = help || '';
     this.validate = validate || (() => {});
 
diff --git a/src/plugins/expressions/common/expression_types/types.ts b/src/plugins/expressions/common/expression_types/types.ts
index 15ec82e40314d..753ff047c8779 100644
--- a/src/plugins/expressions/common/expression_types/types.ts
+++ b/src/plugins/expressions/common/expression_types/types.ts
@@ -32,6 +32,7 @@ export interface ExpressionTypeDefinition<
   SerializedType = undefined
 > {
   name: Name;
+  namespace?: string;
   validate?(type: unknown): void | Error;
   serialize?(type: Value): SerializedType;
   deserialize?(type: SerializedType): Value;
diff --git a/src/plugins/expressions/common/service/expressions_fork.ts b/src/plugins/expressions/common/service/expressions_fork.ts
new file mode 100644
index 0000000000000..b1fb81add183e
--- /dev/null
+++ b/src/plugins/expressions/common/service/expressions_fork.ts
@@ -0,0 +1,140 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import {
+  ExpressionExecutionParams,
+  ExpressionsService,
+  ExpressionsServiceSetup,
+  ExpressionsServiceStart,
+} from '.';
+import { ExpressionAstExpression } from '../ast';
+import { AnyExpressionFunctionDefinition } from '../expression_functions';
+import { AnyExpressionTypeDefinition } from '../expression_types';
+import { AnyExpressionRenderDefinition } from '../expression_renderers';
+
+export interface ExpressionServiceFork {
+  setup(): ExpressionsServiceSetup;
+  start(): ExpressionsServiceStart;
+}
+
+/**
+ * `ExpressionsService` class is used for multiple purposes:
+ *
+ * 1. It implements the same Expressions service that can be used on both:
+ *    (1) server-side and (2) browser-side.
+ * 2. It implements the same Expressions service that users can fork/clone,
+ *    thus have their own instance of the Expressions plugin.
+ * 3. `ExpressionsService` defines the public contracts of *setup* and *start*
+ *    Kibana Platform life-cycles for ease-of-use on server-side and browser-side.
+ * 4. `ExpressionsService` creates a bound version of all exported contract functions.
+ * 5. Functions are bound the way there are:
+ *
+ *    ```ts
+ *    registerFunction = (...args: Parameters<Executor['registerFunction']>
+ *      ): ReturnType<Executor['registerFunction']> => this.executor.registerFunction(...args);
+ *    ```
+ *
+ *    so that JSDoc appears in developers IDE when they use those `plugins.expressions.registerFunction(`.
+ */
+export class ExpressionsServiceFork implements ExpressionServiceFork {
+  /**
+   * @note Workaround since the expressions service is frozen.
+   */
+  constructor(private namespace: string, private expressionsService: ExpressionsService) {
+    this.registerFunction = this.registerFunction.bind(this);
+    this.registerRenderer = this.registerRenderer.bind(this);
+    this.registerType = this.registerType.bind(this);
+    this.run = this.run.bind(this);
+    this.execute = this.execute.bind(this);
+    this.getFunction = this.getFunction.bind(this);
+    this.getFunctions = this.getFunctions.bind(this);
+  }
+
+  protected registerFunction(
+    definition: AnyExpressionFunctionDefinition | (() => AnyExpressionFunctionDefinition)
+  ) {
+    if (typeof definition === 'function') definition = definition();
+    return this.expressionsService.registerFunction({
+      ...definition,
+      namespace: this.namespace,
+    });
+  }
+
+  protected registerRenderer(
+    definition: AnyExpressionRenderDefinition | (() => AnyExpressionRenderDefinition)
+  ) {
+    if (typeof definition === 'function') definition = definition();
+    return this.expressionsService.registerRenderer({
+      ...definition,
+      namespace: this.namespace,
+    });
+  }
+
+  protected registerType(
+    definition: AnyExpressionTypeDefinition | (() => AnyExpressionTypeDefinition)
+  ) {
+    if (typeof definition === 'function') definition = definition();
+    return this.expressionsService.registerType({ ...definition, namespace: this.namespace });
+  }
+
+  protected run<Input, Output>(
+    ast: string | ExpressionAstExpression,
+    input: Input,
+    params?: ExpressionExecutionParams
+  ) {
+    return this.expressionsService.run<Input, Output>(ast, input, {
+      ...params,
+      namespace: this.namespace,
+    });
+  }
+
+  protected execute<Input = unknown, Output = unknown>(
+    ast: string | ExpressionAstExpression,
+    input: Input,
+    params?: ExpressionExecutionParams
+  ) {
+    return this.expressionsService.execute<Input, Output>(ast, input, {
+      ...params,
+      namespace: this.namespace,
+    });
+  }
+
+  protected getFunction(name: string) {
+    return this.expressionsService.getFunction(name, this.namespace);
+  }
+
+  protected getFunctions() {
+    return this.expressionsService.getFunctions(this.namespace);
+  }
+  /**
+   * Returns Kibana Platform *setup* life-cycle contract. Useful to return the
+   * same contract on server-side and browser-side.
+   */
+  public setup(): ExpressionsServiceSetup {
+    return {
+      ...this.expressionsService,
+      registerFunction: this.registerFunction,
+      registerRenderer: this.registerRenderer,
+      registerType: this.registerType,
+    };
+  }
+
+  /**
+   * Returns Kibana Platform *start* life-cycle contract. Useful to return the
+   * same contract on server-side and browser-side.
+   */
+  public start(): ExpressionsServiceStart {
+    return {
+      ...this.expressionsService,
+      run: this.run,
+      execute: this.execute,
+      getFunction: this.getFunction,
+      getFunctions: this.getFunctions,
+    };
+  }
+}
diff --git a/src/plugins/expressions/common/service/expressions_services.test.ts b/src/plugins/expressions/common/service/expressions_services.test.ts
index 620917dc64d4d..8e83cd8e55651 100644
--- a/src/plugins/expressions/common/service/expressions_services.test.ts
+++ b/src/plugins/expressions/common/service/expressions_services.test.ts
@@ -7,6 +7,7 @@
  */
 
 import { ExpressionsService } from './expressions_services';
+import { ExpressionsServiceFork } from './expressions_fork';
 
 describe('ExpressionsService', () => {
   test('can instantiate', () => {
@@ -58,36 +59,31 @@ describe('ExpressionsService', () => {
   describe('.fork()', () => {
     test('returns a new ExpressionsService instance', () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
+      const fork = service.fork('test');
 
       expect(fork).not.toBe(service);
-      expect(fork).toBeInstanceOf(ExpressionsService);
+      expect(fork).toBeInstanceOf(ExpressionsServiceFork);
     });
 
     test('fork keeps all types of the origin service', () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
+      const fork = service.fork('test');
+      const forkStart = fork.start();
 
-      expect(fork.getTypes()).toEqual(service.getTypes());
+      expect(forkStart.getTypes()).toEqual(service.getTypes());
     });
 
     test('fork keeps all functions of the origin service', () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
+      const fork = service.fork('test');
+      const forkStart = fork.start();
 
-      expect(fork.getFunctions()).toEqual(service.getFunctions());
-    });
-
-    test('fork keeps context of the origin service', () => {
-      const service = new ExpressionsService();
-      const fork = service.fork();
-
-      expect(fork.executor.state.context).toEqual(service.executor.state.context);
+      expect(forkStart.getFunctions()).toEqual(service.getFunctions());
     });
 
     test('newly registered functions in origin are also available in fork', () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
+      const fork = service.fork('test');
 
       service.registerFunction({
         name: '__test__',
@@ -96,29 +92,35 @@ describe('ExpressionsService', () => {
         fn: () => {},
       });
 
-      expect(fork.getFunctions()).toEqual(service.getFunctions());
+      const forkStart = fork.start();
+
+      expect(forkStart.getFunctions()).toEqual(service.getFunctions());
     });
 
     test('newly registered functions in fork are NOT available in origin', () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
+      const fork = service.fork('test');
+      const forkSetup = fork.setup();
 
-      fork.registerFunction({
+      forkSetup.registerFunction({
         name: '__test__',
         args: {},
         help: '',
         fn: () => {},
       });
 
-      expect(Object.values(fork.getFunctions())).toHaveLength(
+      const forkStart = fork.start();
+
+      expect(Object.values(forkStart.getFunctions())).toHaveLength(
         Object.values(service.getFunctions()).length + 1
       );
     });
 
     test('fork can execute an expression with newly registered function', async () => {
       const service = new ExpressionsService();
-      const fork = service.fork();
-      fork.start();
+      const fork = service.fork('test');
+      service.start();
+      const forkStart = fork.start();
 
       service.registerFunction({
         name: '__test__',
@@ -129,7 +131,7 @@ describe('ExpressionsService', () => {
         },
       });
 
-      const { result } = await fork.run('__test__', null).toPromise();
+      const { result } = await forkStart.run('__test__', null).toPromise();
 
       expect(result).toBe('123');
     });
@@ -138,7 +140,7 @@ describe('ExpressionsService', () => {
       const service = new ExpressionsService();
       service.start();
 
-      expect(() => service.fork()).toThrow();
+      expect(() => service.fork('test')).toThrow();
     });
   });
 
diff --git a/src/plugins/expressions/common/service/expressions_services.ts b/src/plugins/expressions/common/service/expressions_services.ts
index 416edbea61dfe..f15bb49e4ecf9 100644
--- a/src/plugins/expressions/common/service/expressions_services.ts
+++ b/src/plugins/expressions/common/service/expressions_services.ts
@@ -19,7 +19,11 @@ import { ExecutionContract, ExecutionResult } from '../execution';
 import { AnyExpressionTypeDefinition, ExpressionValueError } from '../expression_types';
 import { AnyExpressionFunctionDefinition } from '../expression_functions';
 import { SavedObjectReference } from '../../../../core/types';
-import { PersistableStateService, VersionedState } from '../../../kibana_utils/common';
+import {
+  MigrateFunctionsObject,
+  PersistableStateService,
+  VersionedState,
+} from '../../../kibana_utils/common';
 import { Adapters } from '../../../inspector/common/adapters';
 import {
   clog,
@@ -36,6 +40,7 @@ import {
   math,
   mathColumn,
 } from '../expression_functions';
+import { ExpressionsServiceFork } from './expressions_fork';
 
 /**
  * The public contract that `ExpressionsService` provides to other plugins
@@ -49,14 +54,14 @@ export interface ExpressionsServiceSetup {
    * service - do not mutate that object.
    * @deprecated Use start contract instead.
    */
-  getFunction(name: string): ReturnType<Executor['getFunction']>;
+  getFunction(name: string, namespace?: string): ReturnType<Executor['getFunction']>;
 
   /**
    * Returns POJO map of all registered expression functions, where keys are
    * names of the functions and values are `ExpressionFunction` instances.
    * @deprecated Use start contract instead.
    */
-  getFunctions(): ReturnType<Executor['getFunctions']>;
+  getFunctions(namespace?: string): ReturnType<Executor['getFunctions']>;
 
   /**
    * Returns POJO map of all registered expression types, where keys are
@@ -75,7 +80,7 @@ export interface ExpressionsServiceSetup {
    * service.
    * @param name A fork name that can be used to get fork instance later.
    */
-  fork(name?: string): ExpressionsService;
+  fork(namespace: string): ExpressionsServiceFork;
 
   /**
    * Register an expression function, which will be possible to execute as
@@ -120,6 +125,8 @@ export interface ExpressionsServiceSetup {
   registerRenderer(
     definition: AnyExpressionRenderDefinition | (() => AnyExpressionRenderDefinition)
   ): void;
+
+  getAllMigrations(): MigrateFunctionsObject;
 }
 
 export interface ExpressionExecutionParams {
@@ -148,6 +155,8 @@ export interface ExpressionExecutionParams {
   inspectorAdapters?: Adapters;
 
   executionContext?: KibanaExecutionContext;
+
+  namespace?: string;
 }
 
 /**
@@ -161,13 +170,13 @@ export interface ExpressionsServiceStart {
    * instance is an internal representation of the function in Expressions
    * service - do not mutate that object.
    */
-  getFunction(name: string): ReturnType<Executor['getFunction']>;
+  getFunction(name: string, namespace?: string): ReturnType<Executor['getFunction']>;
 
   /**
    * Returns POJO map of all registered expression functions, where keys are
    * names of the functions and values are `ExpressionFunction` instances.
    */
-  getFunctions(): ReturnType<Executor['getFunctions']>;
+  getFunctions(namespace?: string): ReturnType<Executor['getFunctions']>;
 
   /**
    * Get a registered `ExpressionRenderer` by its name, which was registered
@@ -238,6 +247,23 @@ export interface ExpressionsServiceStart {
     input: Input,
     params?: ExpressionExecutionParams
   ): ExecutionContract<Input, Output>;
+
+  extract(state: ExpressionAstExpression): {
+    state: ExpressionAstExpression;
+    references: SavedObjectReference[];
+  };
+
+  inject(
+    state: ExpressionAstExpression,
+    references: SavedObjectReference[]
+  ): ExpressionAstExpression;
+
+  telemetry(
+    state: ExpressionAstExpression,
+    telemetryData: Record<string, unknown>
+  ): Record<string, unknown>;
+
+  getAllMigrations(): MigrateFunctionsObject;
 }
 
 export interface ExpressionServiceParams {
@@ -274,9 +300,6 @@ export class ExpressionsService
    * @note Workaround since the expressions service is frozen.
    */
   private static started = new WeakSet<ExpressionsService>();
-  private children = new Map<string, ExpressionsService>();
-  private parent?: ExpressionsService;
-
   public readonly executor: Executor;
   public readonly renderers: ExpressionRendererRegistry;
 
@@ -289,7 +312,7 @@ export class ExpressionsService
   }
 
   private isStarted(): boolean {
-    return !!(ExpressionsService.started.has(this) || this.parent?.isStarted());
+    return ExpressionsService.started.has(this);
   }
 
   private assertSetup() {
@@ -304,11 +327,11 @@ export class ExpressionsService
     }
   }
 
-  public readonly getFunction: ExpressionsServiceStart['getFunction'] = (name) =>
-    this.executor.getFunction(name);
+  public readonly getFunction: ExpressionsServiceStart['getFunction'] = (name, namespace) =>
+    this.executor.getFunction(name, namespace);
 
-  public readonly getFunctions: ExpressionsServiceStart['getFunctions'] = () =>
-    this.executor.getFunctions();
+  public readonly getFunctions: ExpressionsServiceStart['getFunctions'] = (namespace) =>
+    this.executor.getFunctions(namespace);
 
   public readonly getRenderer: ExpressionsServiceStart['getRenderer'] = (name) => {
     this.assertStart();
@@ -342,16 +365,7 @@ export class ExpressionsService
 
   public readonly fork: ExpressionsServiceSetup['fork'] = (name) => {
     this.assertSetup();
-
-    const executor = this.executor.fork();
-    const renderers = this.renderers;
-    const fork = new (this.constructor as typeof ExpressionsService)({ executor, renderers });
-    fork.parent = this;
-
-    if (name) {
-      this.children.set(name, fork);
-    }
-
+    const fork = new ExpressionsServiceFork(name, this);
     return fork;
   };
 
diff --git a/src/plugins/expressions/common/util/get_by_alias.ts b/src/plugins/expressions/common/util/get_by_alias.ts
index 6c6371cccc80f..dec630d27936e 100644
--- a/src/plugins/expressions/common/util/get_by_alias.ts
+++ b/src/plugins/expressions/common/util/get_by_alias.ts
@@ -11,16 +11,33 @@
  * the given object/array for a case-insensitive match, which could be either the
  * `name` itself, or something under the `aliases` property.
  */
-export function getByAlias<T extends { name?: string; aliases?: string[] }>(
+
+export const ALL_NAMESPACES = '*';
+
+interface Node {
+  name?: string;
+  aliases?: string[];
+  namespace?: string;
+}
+
+export function getByAlias<T extends Node>(
   node: T[] | Record<string, T>,
-  nodeName: string
+  nodeName: string,
+  nodeNamespace?: string
 ): T | undefined {
   const lowerCaseName = nodeName.toLowerCase();
-  return Object.values(node).find(({ name, aliases }) => {
+  return Object.values(node).find(({ name, aliases, namespace }) => {
     if (!name) return false;
-    if (name.toLowerCase() === lowerCaseName) return true;
+    if (name.toLowerCase() === lowerCaseName) {
+      if (!namespace || nodeNamespace === ALL_NAMESPACES || namespace === nodeNamespace) {
+        return true;
+      }
+    }
     return (aliases || []).some((alias) => {
-      return alias.toLowerCase() === lowerCaseName;
+      return (
+        alias.toLowerCase() === lowerCaseName &&
+        (!namespace || nodeNamespace === ALL_NAMESPACES || namespace === nodeNamespace)
+      );
     });
   });
 }
diff --git a/src/plugins/expressions/public/mocks.tsx b/src/plugins/expressions/public/mocks.tsx
index 353ae2908b54c..bf5daab911efe 100644
--- a/src/plugins/expressions/public/mocks.tsx
+++ b/src/plugins/expressions/public/mocks.tsx
@@ -23,6 +23,7 @@ const createSetupContract = (): Setup => {
     registerFunction: jest.fn(),
     registerRenderer: jest.fn(),
     registerType: jest.fn(),
+    getAllMigrations: jest.fn(),
   };
   return setupContract;
 };
@@ -40,6 +41,10 @@ const createStartContract = (): Start => {
     render: jest.fn(),
     ReactExpressionRenderer: jest.fn((props) => <></>),
     run: jest.fn(),
+    telemetry: jest.fn(),
+    extract: jest.fn(),
+    inject: jest.fn(),
+    getAllMigrations: jest.fn(),
   };
 };
 
diff --git a/src/plugins/expressions/public/plugin.test.ts b/src/plugins/expressions/public/plugin.test.ts
index 61ff0d8b54033..f3bab4e2732e4 100644
--- a/src/plugins/expressions/public/plugin.test.ts
+++ b/src/plugins/expressions/public/plugin.test.ts
@@ -8,7 +8,7 @@
 
 import { expressionsPluginMock } from './mocks';
 import { add } from '../common/test_helpers/expression_functions/add';
-import { ExpressionsService } from './services';
+import { ExpressionsServiceFork } from '../common/service/expressions_fork';
 
 describe('ExpressionsPublicPlugin', () => {
   test('can instantiate from mocks', async () => {
@@ -19,9 +19,9 @@ describe('ExpressionsPublicPlugin', () => {
   describe('setup contract', () => {
     test('.fork() method returns ExpressionsService', async () => {
       const { setup } = await expressionsPluginMock.createPlugin();
-      const fork = setup.fork();
+      const fork = setup.fork('test');
 
-      expect(fork).toBeInstanceOf(ExpressionsService);
+      expect(fork).toBeInstanceOf(ExpressionsServiceFork);
     });
 
     describe('.registerFunction()', () => {
diff --git a/src/plugins/expressions/server/mocks.ts b/src/plugins/expressions/server/mocks.ts
index bf36ab3c5daa9..cb6392e04fc9e 100644
--- a/src/plugins/expressions/server/mocks.ts
+++ b/src/plugins/expressions/server/mocks.ts
@@ -21,6 +21,7 @@ const createSetupContract = (): Setup => ({
   registerFunction: jest.fn(),
   registerRenderer: jest.fn(),
   registerType: jest.fn(),
+  getAllMigrations: jest.fn(),
 });
 
 const createStartContract = (): Start =>
@@ -30,6 +31,10 @@ const createStartContract = (): Start =>
     getRenderer: jest.fn(),
     getType: jest.fn(),
     run: jest.fn(),
+    telemetry: jest.fn(),
+    extract: jest.fn(),
+    inject: jest.fn(),
+    getAllMigrations: jest.fn(),
   } as unknown as Start);
 
 const createPlugin = async () => {
diff --git a/x-pack/plugins/canvas/public/services/kibana/expressions.ts b/x-pack/plugins/canvas/public/services/kibana/expressions.ts
index ea329b63863f8..6174c56aa2b71 100644
--- a/x-pack/plugins/canvas/public/services/kibana/expressions.ts
+++ b/x-pack/plugins/canvas/public/services/kibana/expressions.ts
@@ -52,7 +52,7 @@ export class ExpressionsService {
     context?: ExpressionExecutionParams
   ): Promise<ExpressionValue> {
     return await this.expressions
-      .execute(ast, input, context)
+      .execute(ast, input, { ...context, namespace: 'canvas' })
       .getData()
       .pipe(pluck('result'))
       .toPromise();
diff --git a/x-pack/plugins/canvas/public/services/stubs/expressions.ts b/x-pack/plugins/canvas/public/services/stubs/expressions.ts
index 405f2ebe0ba91..776b553b75d55 100644
--- a/x-pack/plugins/canvas/public/services/stubs/expressions.ts
+++ b/x-pack/plugins/canvas/public/services/stubs/expressions.ts
@@ -29,12 +29,13 @@ export const expressionsServiceFactory: CanvasExpressionsServiceFactory = (
   const placeholder = {} as any;
   const expressionsPlugin = plugin(placeholder);
   const setup = expressionsPlugin.setup(placeholder);
-  const expressionsService = setup.fork();
+  const fork = setup.fork('canvas');
+  const expressionsService = fork.setup();
 
   functionDefinitions.forEach((fn) => expressionsService.registerFunction(fn));
   renderFunctions.forEach((fn) => {
-    expressionsService.registerRenderer(fn as unknown as AnyExpressionRenderDefinition);
+    setup.registerRenderer(fn as unknown as AnyExpressionRenderDefinition);
   });
 
-  return new ExpressionsService(expressionsService, requiredServices);
+  return new ExpressionsService(fork.start(), requiredServices);
 };
diff --git a/x-pack/plugins/canvas/server/plugin.ts b/x-pack/plugins/canvas/server/plugin.ts
index 172d1e8dd8bf1..de4d452508cf2 100644
--- a/x-pack/plugins/canvas/server/plugin.ts
+++ b/x-pack/plugins/canvas/server/plugin.ts
@@ -52,9 +52,9 @@ export class CanvasPlugin implements Plugin {
   }
 
   public setup(coreSetup: CoreSetup<PluginsStart>, plugins: PluginsSetup) {
-    const expressionsFork = plugins.expressions.fork();
-
-    setupInterpreter(expressionsFork, {
+    const expressionsFork = plugins.expressions.fork('canvas');
+    const expressionsSetup = expressionsFork.setup();
+    setupInterpreter(expressionsSetup, {
       embeddablePersistableStateService: {
         extract: plugins.embeddable.extract,
         inject: plugins.embeddable.inject,
@@ -62,7 +62,7 @@ export class CanvasPlugin implements Plugin {
       },
     });
 
-    const deps: CanvasSavedObjectTypeMigrationsDeps = { expressions: expressionsFork };
+    const deps: CanvasSavedObjectTypeMigrationsDeps = { expressions: expressionsSetup };
     coreSetup.uiSettings.register(getUISettings());
     coreSetup.savedObjects.registerType(customElementType(deps));
     coreSetup.savedObjects.registerType(workpadTypeFactory(deps));
@@ -70,7 +70,8 @@ export class CanvasPlugin implements Plugin {
 
     plugins.features.registerKibanaFeature(getCanvasFeature(plugins));
 
-    const contextProvider = createWorkpadRouteContext({ expressions: expressionsFork });
+    const expressionsStart = expressionsFork.start();
+    const contextProvider = createWorkpadRouteContext({ expressions: expressionsStart });
     coreSetup.http.registerRouteHandlerContext<CanvasRouteHandlerContext, 'canvas'>(
       'canvas',
       contextProvider
@@ -80,7 +81,7 @@ export class CanvasPlugin implements Plugin {
 
     initRoutes({
       router: canvasRouter,
-      expressions: expressionsFork,
+      expressions: expressionsSetup,
       bfetch: plugins.bfetch,
       logger: this.logger,
     });
diff --git a/x-pack/plugins/canvas/server/routes/functions/functions.ts b/x-pack/plugins/canvas/server/routes/functions/functions.ts
index ed1559034c3a6..47b35a4f6c17b 100644
--- a/x-pack/plugins/canvas/server/routes/functions/functions.ts
+++ b/x-pack/plugins/canvas/server/routes/functions/functions.ts
@@ -23,7 +23,7 @@ export function initializeGetFunctionsRoute(deps: RouteInitializerDeps) {
       validate: false,
     },
     async (context, request, response) => {
-      const functions = expressions.getFunctions();
+      const functions = expressions.getFunctions('canvas');
       const body = JSON.stringify(functions);
       return response.ok({
         body,
@@ -39,7 +39,7 @@ export function initializeBatchFunctionsRoute(deps: RouteInitializerDeps) {
     const { functionName, args, context } = fnCall;
     const { deserialize } = serializeProvider(expressions.getTypes());
 
-    const fnDef = expressions.getFunctions()[functionName];
+    const fnDef = expressions.getFunctions('canvas')[functionName];
     if (!fnDef) throw new Error(`Function "${functionName}" could not be found.`);
 
     const deserialized = deserialize(context);
diff --git a/x-pack/plugins/canvas/server/saved_objects/migrations/types.ts b/x-pack/plugins/canvas/server/saved_objects/migrations/types.ts
index 18ce0bd88cb69..0b7c26d69f7eb 100644
--- a/x-pack/plugins/canvas/server/saved_objects/migrations/types.ts
+++ b/x-pack/plugins/canvas/server/saved_objects/migrations/types.ts
@@ -4,8 +4,8 @@
  * 2.0; you may not use this file except in compliance with the Elastic License
  * 2.0.
  */
-import { ExpressionsService } from 'src/plugins/expressions/public';
+import { ExpressionsServiceSetup } from 'src/plugins/expressions/public';
 
 export interface CanvasSavedObjectTypeMigrationsDeps {
-  expressions: ExpressionsService;
+  expressions: ExpressionsServiceSetup;
 }
diff --git a/x-pack/plugins/canvas/server/workpad_route_context.ts b/x-pack/plugins/canvas/server/workpad_route_context.ts
index d7c818b786e32..2e4cad231dd84 100644
--- a/x-pack/plugins/canvas/server/workpad_route_context.ts
+++ b/x-pack/plugins/canvas/server/workpad_route_context.ts
@@ -11,7 +11,7 @@ import {
   SavedObject,
   SavedObjectsResolveResponse,
 } from 'kibana/server';
-import { ExpressionsService } from 'src/plugins/expressions';
+import { ExpressionsServiceStart } from 'src/plugins/expressions';
 import { WorkpadAttributes } from './routes/workpad/workpad_attributes';
 import { CANVAS_TYPE } from '../common/lib/constants';
 import { injectReferences, extractReferences } from './saved_objects/workpad_references';
@@ -34,7 +34,7 @@ export interface CanvasRouteHandlerContext extends RequestHandlerContext {
 }
 
 interface Deps {
-  expressions: ExpressionsService;
+  expressions: ExpressionsServiceStart;
 }
 
 export const createWorkpadRouteContext: (