Base Sepolia → Stellar Testnet

End-to-end testnet bridges from Base Sepolia USDC to Stellar testnet USDC, covering both Stellar destination types:

• G-address (classic Stellar account) — payout via Horizon Operation.payment

• C-address (Soroban smart-contract account, e.g. smart wallets, AMMs) — payout via the Stellar Asset Contract (SAC) transfer(from, to, i128) over Soroban RPC

Both flows hit the public testnet API at:

https://intentapitestnet.rozo.ai

No auth header required. USDC only. Amount range 0.01–1.00. Order TTL 10 min.

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Scripts

Script	Destination	Default amount
testnet-base-to-stellar.sh	G-address (G…)	0.01
testnet-base-to-stellar-c.sh	C-address (C…)	0.02

Both scripts:

1. POST /payments with type=exactIn, source.chainId=84532 (Base Sepolia), destination.chainId=1500 (Stellar testnet).

2. Print the returned source.receiverAddress (Rozo hub) and source.amount (may be auto-incremented by $0.01 for collision avoidance).

3. Either pause for a manual deposit, or — with AUTO=1 — auto-broadcast using the test keys in .env.dev.

4. Poll GET /payments/{id} until payment_completed, payment_bounced, or payment_expired.

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Quick start

# Manual deposit (you send the USDC yourself from any wallet)
bash testnet/testnet-base-to-stellar.sh 0.01
bash testnet/testnet-base-to-stellar-c.sh 0.02

# Auto-deposit using TEST_EVM_PAYER_PRIVATE_KEY
AUTO=1 bash testnet/testnet-base-to-stellar.sh 0.01
AUTO=1 bash testnet/testnet-base-to-stellar-c.sh 0.02

Override the C-address destination:

AUTO=1 bash testnet/testnet-base-to-stellar-c.sh 0.02 CCYO2DDE3ZWBGGRTGOWJOV4KO2HLXHCT7WN7TH7BOYUGQMXTGKWU4IGV

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.env.dev requirements

Variable	Purpose
TEST_EVM_PAYER_PRIVATE_KEY + TEST_EVM_PAYER_ADDRESS	Source-side signer (Base Sepolia)
TEST_STELLAR_RECEIVER_ADDRESS	Default G-address destination
TEST_STELLAR_C_RECEIVER_ADDRESS	Default C-address destination

Generate fresh test keys: npx tsx scripts/gen-hub-keys.ts --test-wallets. Fund payer at the Circle USDC faucet and Alchemy Base Sepolia faucet.

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What's different about the C-address payout

A Stellar C-address is a Soroban contract identifier, not a classic account. Three differences vs. the G-path:

1. No memo_text. Soroban contract calls have no memo field. Any memo passed in the order is dropped with a log warning.

2. SAC contract call, not payment op. The hub invokes transfer(from, to, i128) on the auto-deployed Stellar Asset Contract for USDC. The contract id is derived deterministically from (asset, networkPassphrase).

3. Submitted via Soroban RPC, not Horizon. Status is polled with getTransaction(hash) and the meta returned is Protocol-23 TransactionMeta v4 — make sure any client decoding it uses @stellar/stellar-sdk ≥ 15 (older SDKs throw Bad union switch: 4 on the decode).

The order schema is identical for both — clients pass destination.receiverAddress as either a G… or a C… and the API routes correctly.

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Verified end-to-end run

A run of testnet-base-to-stellar-c.sh 0.02 against CCYO2DDE3ZWBGGRTGOWJOV4KO2HLXHCT7WN7TH7BOYUGQMXTGKWU4IGV:

Payment id : pay_ewHL66ke5XdqP7GLZ8xnkVPh
Send TO    : 0x4843B70de3Aa77CFbfDA0BAf468e3C4f32B1FA34
Send AMOUNT: 0.03 USDC (Base Sepolia)   ← 0.02 + $0.01 collision step
Dest C-addr: CCYO2DDE3ZWBGGRTGOWJOV4KO2HLXHCT7WN7TH7BOYUGQMXTGKWU4IGV
…
[1] status = payment_unpaid
[2] status = payment_completed

Leg	Tx hash	Confirmation
Base Sepolia payin (USDC → hub)	0x92d4ed6ab6270c9d7e0db4b251ccd2c8aef41f9be311678491e6cf6caa199237	block 41065985, success
Stellar payout (SAC transfer → C-address)	e7eedc04fb5605550a0e5c8c98ad310fe26f93b3bee5c6bf65af24d6477c4572	ledger 2378571, SUCCESS, 0.0300000 USDC credited to the contract

End-to-end time: ~10 seconds.

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Status transitions

payment_unpaid → payment_payin_completed → payment_completed   (happy path)
payment_unpaid → payment_expired                                 (TTL)
              ↘ payment_bounced                                   (payout error)

payment_bounced with errorMessage: "Bad union switch: 4" on a C-address destination means the deployed payout function is on an outdated @stellar/stellar-sdk (Protocol 23 TransactionMeta decoding broke pre-15.0). Bump the SDK and redeploy.