How to Create an App for IC Pack Package Manager in 2025

This project failed for technical reaasons: We need to go through all intermediary versions when doing a package upgrade, to run all migration functions. So, I had the idea to update the remote repo on Git commits. But the binaries for the production and localhost tests may be different, this makes it nearly impossible to do correctly. If you have an idea how to save my project, please I to hear you.

To create an app for IC Pack package manager (a remote, installable app), you follow these guidelines.

Choice of programming language

Motoko (a special programming language for ICP blockchain). Don’t afraid of a new language: Motoko is a easy as Python to learn, meanwhile having features of a strict type system, helping you to eliminate stupid errors due to messed types and increasing code execution speed (and reducing costs).
Rust (A bit of advice: because we hold all data in VM memory, not on disk files or an external database, memory corruption would be especially bad, so I recommend to never use unsafe Rust feature. To create circular data structures Better use Rc or Arc reference counting pointers than to resort to unsafe.)
TypeScript or JavaScript (Azle);
Python (Kybra);
C++ (icpp-pro).

So, if you write a new software for Internet Computer (including software for our project IC Pack), choose either Motoko or Rust. If you decide to translate existing software, Rust, TypeScript, javaScript, Python, or C++ may be good choices.

Do development using ICP blockchain

Learn to develop software using ICP blockchain. It is easier than to develop for AWS or GCP.

Creating a package

For your software to be compatible with IC Pack, you need to package it (or, in other words, create a package). IC Pack dev docs explain how to do it.

Use wallet app (src/wallet_backend/ and src/wallet_frontend/) as an example how a package should work, especially, how to initialize package’s owner principal in a secure manner.

You can optionally make your package paid (see paid-wallet package for an example). You specify the (non-zero) price and developer account for a paid package. Your customers pay us a 10% fee for installing a paid package. If you omit the developer account, 100% will be paid to us.

Module initialization arguments

Every module of your package receives the following arguments on installation:

{
  packageManager: Principal; // `backend` module of the package manager
  mainIndirect: Principal; // `main_indirect` module of the package manager
  simpleIndirect: Principal; // `simple_indirect` module of the package manager
  battery: Principal; // `battery` module of the package manager
  user: Principal; // user, ignore it for now, use install key instead  installationId: Nat; // installation ID of the currently installed package
  upgradeId: ?Nat; // `null` for newly installed packages  userArg: Blob; // normally `to_candid({})` but maybe any value
}

Example package receiving arguments:

persistent actor class Wallet({
  installationId: Nat;
  packageManager: Principal;
}) = this {
  // ...
}

Usually, you need to set the owner of your backend canister. The highly recommended (because it has enhanced security) way to do it is:

Frontend JS code:

import { urlSafeBase64ToUint8Array, signPrincipal } from '../../../icpack-js';

const params = new URLSearchParams(window.location.search);
const installKey = params.get('installationPrivKey');

try {
  privBytes = urlSafeBase64ToUint8Array(props.installationPrivKey);
} catch (_) {
  alert('Invalid installation key.');
  return;
}
const privKey = await window.crypto.subtle.importKey(
  "pkcs8", privBytes, {name: 'ECDSA', namedCurve: 'P-256'/*prime256v1*/}, true, ["sign"]
);
const signature = new Uint8Array(await signPrincipal(privKey, principal));
await backend.setOwner(signature); // the code that you use to set your canister owner

In the backend, check the user’s cryptographic signature before setting the owner. Here is the Motoko code:

import UserAuth "mo:icpack-lib/UserAuth";

public shared({caller}) func setOwner(signature: Blob): async () {
  await* UserAuth.checkOwnerSignature(packageManager, installationId, caller, signature); // traps on error
  owner := caller;
};

Distribute your software

Distributing your software is the simplest task! Just create a link, as IC Pack dev docs explain.

IC Pack