example-auto-join

A library and demo app for fetching and joining Aleo records using the Provable SDK. Supports credits.aleo and token registry programs on both testnet and mainnet.

AutoJoin Library

The library lives in src/aleo/ and provides two main building blocks:

• AleoClient — wraps the Provable SDK to handle network initialization, JWT auth, record scanning, and delegated proving.
• AutoJoinClient — orchestrates joining records using a pluggable JoinStrategy.

JoinStrategy

A JoinStrategy controls how records are joined. Two strategies are included:

BasicAutoJoinStrategy

Calls the standard join(recordA, recordB) transition directly on the token's own program. Works with any token that exposes a join transition.

Timing: Joins records in pairs across parallel rounds. Reducing N records requires ⌈log₂ N⌉ rounds of on-chain confirmations (e.g. 16 records → 4 rounds). The rounds execute multiple join transactions with a total of: 8 + 4 + 2 + 1 = 15 transactions.

BatchAutoJoinStrategy

Calls join_N transitions on dedicated batch wrapper programs (e.g. autojoin_credits_2_10.aleo) that accept 2–16 records in a single transaction.

Supported programs: Same base set as BasicAutoJoinStrategy, but only programs that have deployed batch wrappers on-chain. Arbitrary tokens with a join transition are not supported. More on chain programs can be deployed to support batch joining of other tokens. We expect to deploy a generic "dynamic dispatch" batch join program later this year (2026).

Timing: Up to 16 records collapse in one transaction. Most joins complete in a single confirmation round, making this significantly faster than BasicAutoJoinStrategy for large record sets. Ex. 32 records can be joined in 2 rounds of 3 total transactions.

Cost: The batch programs introduce a small gas fee cost overhead over just using the built-in join calls, however in practice this is very small in absolute terms due to the low cost of the Aleo network transactions.

	BasicAutoJoinStrategy	BatchAutoJoinStrategy
Works with any join token	Yes	No — requires batch wrapper programs
Records per transaction	2	2–16
Rounds to join N records	⌈log₂ N⌉	⌈log₁₆ N⌉

You can provide your own strategy by implementing the interface:

interfaceJoinStrategy{isSupportedProgram(programName: string): boolean;joinRecords(records: AleoRecord[]): Promise<AleoRecord>;}

Example: Fetch and Join Records

1. Initialize the client

import{AleoClient}from'./src/aleo/aleoClient';import{AutoJoinClient}from'./src/aleo/autojoin/autoJoinClient';import{BasicAutoJoinStrategy}from'./src/aleo/autojoin/strategies/basicAutoJoinStrategy';constaleoClient=newAleoClient('testnet',{apiKey: 'YOUR_API_KEY',consumerId: 'YOUR_CONSUMER_ID',apiRoot: 'https://api.provable.com',// optional, this is the default});// Must be called before any other operationsawaitaleoClient.initNetwork();

2. Derive an account from a private key

constaccount=aleoClient.accountFromPrivateKey('APrivateKey1zkp...');

3. Register the account for record scanning

Registers the account's view key with the record scanner. Idempotent — safe to call multiple times.

awaitaleoClient.registerAccountForRecordScanning(account);

4. Fetch unspent records

constrecords=awaitaleoClient.fetchUnspentRecords(account,['credits.aleo'],// one or more program names to filter byaccount.address().to_string()// optional; derived from account if omitted);for(constrecordofrecords){console.log(record.programName);// e.g. 'credits.aleo'console.log(record.transactionId);// transaction that created this recordconsole.log(record.amount);// microcredits as a string, undefined if not parseable}

5. Join records

Reduces any number of records down to one by pairing and joining them in parallel rounds.

constautoJoinClient=newAutoJoinClient(aleoClient,account,BasicAutoJoinStrategy);constjoinedRecord=awaitautoJoinClient.joinRecords(records);console.log('Final record tx:',joinedRecord.transactionId);

joinRecords validates that all records share the same program, are owned by the same address, are supported by the strategy, and each have a transactionId. It throws a descriptive error if any condition is not met or if on-chain confirmation times out.

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Demo Frontend

The React demo app lets you enter a private key, browse unspent records for a selected program, and trigger a join across all loaded records.

Setup

Copy the environment template and fill in your credentials:

cp .env.example .env

Variable	Description
VITE_PROVABLE_API_KEY	Your Provable API key
VITE_PROVABLE_CONSUMER_ID	Your Provable consumer ID
VITE_PROVABLE_API_ROOT	API root URL (optional, defaults to https://api.provable.com)
VITE_DEFAULT_PKEY	Pre-fills the private key input (optional, development only)

Commands

# Install dependencies
pnpm install
# Start the development server (http://localhost:5173)
pnpm dev
# Type-check and build for production
pnpm build
# Preview the production build locally
pnpm preview