diff --git a/src/userlib/js/src/actor.ts b/src/userlib/js/src/actor.ts
index bf0e6b4d14..68961c74ea 100644
--- a/src/userlib/js/src/actor.ts
+++ b/src/userlib/js/src/actor.ts
@@ -3,7 +3,6 @@ import { CanisterId } from './canisterId';
 import { HttpAgent } from './http_agent';
 import { QueryResponseStatus, RequestStatusResponseStatus } from './http_agent_types';
 import * as IDL from './idl';
-import { FuncClass } from './idl';
 import { RequestId, toHex as requestIdToHex } from './request_id';
 import { BinaryBlob } from './types';
 
@@ -14,6 +13,16 @@ import { BinaryBlob } from './types';
 export type Actor = Record<string, (...args: unknown[]) => Promise<unknown>> & {
   __canisterId(): string;
   __getAsset(path: string): Promise<Uint8Array>;
+  __install(
+    fields: {
+      module: BinaryBlob;
+      arg?: BinaryBlob;
+    },
+    options?: {
+      maxAttempts?: number;
+      throttleDurationInMSecs?: number;
+    },
+  ): Promise<void>;
 };
 
 export interface ActorConfig {
@@ -83,7 +92,7 @@ export function makeActorFactory(
   async function requestStatusAndLoop(
     httpAgent: HttpAgent,
     requestId: RequestId,
-    func: FuncClass,
+    returnType: IDL.Type[],
     attempts: number,
     maxAttempts: number,
     throttle: number,
@@ -92,7 +101,7 @@ export function makeActorFactory(
 
     switch (status.status) {
       case RequestStatusResponseStatus.Replied: {
-        return decodeReturnValue(func.retTypes, status.reply.arg);
+        return decodeReturnValue(returnType, status.reply.arg);
       }
 
       case RequestStatusResponseStatus.Unknown:
@@ -107,7 +116,7 @@ export function makeActorFactory(
 
         // Wait a little, then retry.
         return new Promise(resolve => setTimeout(resolve, throttle)).then(() =>
-          requestStatusAndLoop(httpAgent, requestId, func, attempts, maxAttempts, throttle),
+          requestStatusAndLoop(httpAgent, requestId, returnType, attempts, maxAttempts, throttle),
         );
 
       case RequestStatusResponseStatus.Rejected:
@@ -138,6 +147,47 @@ export function makeActorFactory(
 
         return agent.retrieveAsset(canisterId, path);
       },
+      async __install(
+        fields: {
+          module: BinaryBlob;
+          arg?: BinaryBlob;
+        },
+        options: {
+          maxAttempts?: number;
+          throttleDurationInMSecs?: number;
+        } = {},
+      ) {
+        const agent = httpAgent || getDefaultHttpAgent();
+        if (!agent) {
+          throw new Error('Cannot make call. httpAgent is undefined.');
+        }
+
+        // Resolve the options that can be used globally or locally.
+        const effectiveMaxAttempts = options.maxAttempts?.valueOf() || 0;
+        const effectiveThrottle = options.throttleDurationInMSecs?.valueOf() || 0;
+
+        const { requestId, response } = await agent.install(canisterId, fields);
+        if (!response.ok) {
+          throw new Error(
+            [
+              'Install failed:',
+              `  Canister ID: ${cid.toHex()}`,
+              `  Request ID: ${requestIdToHex(requestId)}`,
+              `  HTTP status code: ${response.status}`,
+              `  HTTP status text: ${response.statusText}`,
+            ].join('\n'),
+          );
+        }
+
+        return requestStatusAndLoop(
+          agent,
+          requestId,
+          [],
+          effectiveMaxAttempts,
+          effectiveMaxAttempts,
+          effectiveThrottle,
+        );
+      },
     } as Actor;
 
     for (const [methodName, func] of Object.entries(actorInterface._fields)) {
@@ -181,7 +231,7 @@ export function makeActorFactory(
           return requestStatusAndLoop(
             agent,
             requestId,
-            func,
+            func.retTypes,
             maxAttempts,
             maxAttempts,
             throttleDurationInMSecs,
diff --git a/src/userlib/js/src/canisterId.ts b/src/userlib/js/src/canisterId.ts
index 1d40088465..8b7942d91b 100644
--- a/src/userlib/js/src/canisterId.ts
+++ b/src/userlib/js/src/canisterId.ts
@@ -4,12 +4,16 @@ export class CanisterId {
     if (hex.startsWith('ic:')) {
       // Remove the checksum from the hexadecimal.
       // TODO: validate the checksum.
-      return new this(hex.slice(3, -2));
+      return this.fromHex(hex.slice(3, -2));
     } else {
-      throw new Error('CanisterId not a ic: url: ' + hex);
+      throw new Error('CanisterId not a "ic:" url: ' + hex);
     }
   }
 
+  private static fromHex(hex: string): CanisterId {
+    return new this(hex);
+  }
+
   protected constructor(private _idHex: string) {}
 
   public toHex(): string {
diff --git a/src/userlib/js/src/cbor.ts b/src/userlib/js/src/cbor.ts
index 6d0f55b13c..66703f1a8d 100644
--- a/src/userlib/js/src/cbor.ts
+++ b/src/userlib/js/src/cbor.ts
@@ -52,7 +52,7 @@ class BufferEncoder implements CborEncoder<Buffer> {
   }
 
   public encode(v: Buffer): cbor.CborValue {
-    return cbor.value.bytes(new Uint8Array(v.buffer));
+    return cbor.value.bytes(new Uint8Array(v));
   }
 }
 
diff --git a/src/userlib/js/src/http_agent.test.ts b/src/userlib/js/src/http_agent.test.ts
index 425c8440dc..255c2ffb23 100644
--- a/src/userlib/js/src/http_agent.test.ts
+++ b/src/userlib/js/src/http_agent.test.ts
@@ -66,7 +66,7 @@ test('call', async () => {
     ...mockPartialRequest,
     sender_pubkey: keyPair.publicKey,
     sender_sig: senderSig,
-  };
+  } as CallRequest;
 
   const expectedRequestId = await requestIdOf(expectedRequest);
   expect(expectedRequestId).toEqual(mockPartialsRequestId);
diff --git a/src/userlib/js/src/http_agent.ts b/src/userlib/js/src/http_agent.ts
index a6582afce2..a733eafa61 100644
--- a/src/userlib/js/src/http_agent.ts
+++ b/src/userlib/js/src/http_agent.ts
@@ -23,7 +23,7 @@ import {
 } from './http_agent_types';
 import * as IDL from './idl';
 import { requestIdOf } from './request_id';
-import { BinaryBlob } from './types';
+import { BinaryBlob, blobFromHex } from './types';
 const API_VERSION = 'v1';
 
 // HttpAgent options that can be used at construction.
@@ -153,6 +153,21 @@ export class HttpAgent {
     });
   }
 
+  public install(
+    canisterId: CanisterId | string,
+    fields: {
+      module: BinaryBlob;
+      arg?: BinaryBlob;
+    },
+  ): Promise<SubmitResponse> {
+    return this.submit({
+      request_type: SubmitRequestType.InstallCode,
+      canister_id: typeof canisterId === 'string' ? CanisterId.fromText(canisterId) : canisterId,
+      module: fields.module,
+      arg: fields.arg || blobFromHex(''),
+    });
+  }
+
   public query(canisterId: CanisterId | string, fields: QueryFields): Promise<QueryResponse> {
     return this.read({
       request_type: ReadRequestType.Query,
diff --git a/src/userlib/js/src/http_agent_types.ts b/src/userlib/js/src/http_agent_types.ts
index e11f0217b1..8ef0a63c6e 100644
--- a/src/userlib/js/src/http_agent_types.ts
+++ b/src/userlib/js/src/http_agent_types.ts
@@ -48,14 +48,21 @@ export interface CallRequest extends Record<string, any> {
   method_name: string;
   arg: BinaryBlob;
 }
+export interface InstallCodeRequest extends Record<string, any> {
+  request_type: SubmitRequestType.InstallCode;
+  canister_id: CanisterId;
+  module: BinaryBlob;
+  arg?: BinaryBlob;
+}
 // tslint:enable:camel-case
 
 // The types of values allowed in the `request_type` field for submit requests.
 export enum SubmitRequestType {
   Call = 'call',
+  InstallCode = 'install_code',
 }
 
-export type SubmitRequest = CallRequest;
+export type SubmitRequest = CallRequest | InstallCodeRequest;
 export interface SubmitResponse {
   requestId: RequestId;
   response: Response;
diff --git a/src/userlib/js/src/index.ts b/src/userlib/js/src/index.ts
index 2f13d44199..eb21142d31 100644
--- a/src/userlib/js/src/index.ts
+++ b/src/userlib/js/src/index.ts
@@ -4,6 +4,7 @@ export * from './canisterId';
 export * from './http_agent';
 export * from './http_agent_transforms';
 export * from './http_agent_types';
+export * from './types';
 
 import * as IDL from './idl';
 export { IDL };
diff --git a/src/userlib/js/src/request_id.ts b/src/userlib/js/src/request_id.ts
index d547658af2..2afce2b3b0 100644
--- a/src/userlib/js/src/request_id.ts
+++ b/src/userlib/js/src/request_id.ts
@@ -2,6 +2,7 @@ import borc from 'borc';
 import { Buffer } from 'buffer/';
 import { CanisterId } from './canisterId';
 import { BinaryBlob, blobFromHex, blobToHex } from './types';
+import { lebEncode } from './utils/leb128';
 
 export type RequestId = BinaryBlob & { __requestId__: void };
 export function toHex(requestId: RequestId): string {
@@ -23,6 +24,8 @@ async function hashValue(value: unknown): Promise<Buffer> {
     return hashValue(value.value);
   } else if (typeof value === 'string') {
     return hashString(value);
+  } else if (typeof value === 'number') {
+    return hash(lebEncode(value) as BinaryBlob);
   } else if (value instanceof CanisterId) {
     // HTTP handler expects canister_id to be an u64 & hashed in this way.
     // work-around for endianness problem until we switch to blobs
diff --git a/src/userlib/js/src/utils/leb128.ts b/src/userlib/js/src/utils/leb128.ts
index e0767f87ab..399a60b57d 100644
--- a/src/userlib/js/src/utils/leb128.ts
+++ b/src/userlib/js/src/utils/leb128.ts
@@ -1,4 +1,11 @@
 // tslint:disable:no-bitwise
+// Note: this file uses buffer-pipe, which on Node only, uses the Node Buffer
+//       implementation, which isn't compatible with the NPM buffer package
+//       which we use everywhere else. This means that we have to transform
+//       one into the other, hence why every function that returns a Buffer
+//       actually return `new Buffer(pipe.buffer)`.
+// TODO: The best solution would be to have our own buffer type around
+//       Uint8Array which is standard.
 import BigNumber from 'bignumber.js';
 import Pipe = require('buffer-pipe');
 import { Buffer } from 'buffer/';
@@ -24,7 +31,7 @@ export function lebEncode(value: number | BigNumber): Buffer {
     }
   }
 
-  return pipe.buffer;
+  return new Buffer(pipe.buffer);
 }
 
 export function lebDecode(pipe: Pipe): BigNumber {
@@ -73,7 +80,7 @@ export function slebEncode(value: BigNumber | number): Buffer {
       return bytes;
     }
   }
-  return pipe.buffer;
+  return new Buffer(pipe.buffer);
 }
 
 export function slebDecode(pipe: Pipe): BigNumber {
@@ -128,7 +135,7 @@ export function writeIntLE(value: BigNumber | number, byteLength: number): Buffe
     pipe.write([byte]);
     mul = mul.times(256);
   }
-  return pipe.buffer;
+  return new Buffer(pipe.buffer);
 }
 
 export function readUIntLE(pipe: Pipe, byteLength: number): BigNumber {