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Tasra SDK

Fund a slot for use

Creating a slot prepares its key and access policy. Before signing or decrypting, add TASRA usage credits. The token symbol used by the SDK is TSRA.

There are three steps:

  1. Send AVAX to the creator wallet to pay transaction gas.
  2. Buy TSRA with EURC from the network’s BondingCurve contract.
  3. Deposit TSRA into the slot’s Settlement balance.

AVAX is not sent to a slot ID. An Ethereum slot’s derived account separately needs AVAX when it sends Ethereum transactions. Its account balance is not usage credit.

1. Fund the creator with AVAX

Section titled “1. Fund the creator with AVAX”

Run the creation lesson to print your saved creator address. For the downloaded Fuji manifest, use the official Avalanche Fuji C-Chain faucet and send test AVAX to that 0x address on chain 43113. The faucet may require eligibility or a coupon; see Avalanche’s instructions. You can also transfer AVAX from a wallet you control on the same network.

Keep enough AVAX for creation, token approvals, purchases and deposits. Then rerun creation. A nonzero gas balance does not guarantee every transaction can be paid.

2. Inspect the saved account and slot

Section titled “2. Inspect the saved account and slot”

Continue in the same project with its original network.json, network-pin.json and private .tasra/ state. Copy the funding command:

Terminal window
cp node_modules/tasra-sdk/examples/fund-slot.ts .
npx tsc --noEmit
npx tsx fund-slot.ts .tasra/first-slot status

For an application tutorial, replace .tasra/first-slot with the directory printed by that app. It prints a complete status command when its slot needs credit. The command restores the creator key; it never creates a replacement account.

Keep a terminal demo running while funding it in a second terminal, from the same project directory. It waits up to 15 minutes. If it has exited, rerunning that demo creates fresh state; funding its old slot will not resume the exited run. The first-slot lessons and the web document app save state for later runs.

3. Buy TSRA with EURC

Section titled “3. Buy TSRA with EURC”

The curve accepts EURC, not AVAX. The funding helper reads the curve’s EURC token address from the contract named by your verified manifest; the manifest may omit a separate token entry. The Fuji deployment uses test EURC; this optional command explicitly mints 10 test EURC to the saved creator:

Terminal window
npx tsx fund-slot.ts .tasra/first-slot mint-test-eurc 10000000

The SDK permits this only for a supported mock token. Real EURC must be acquired and transferred to your creator wallet; it cannot be minted with this command.

Choose how much EURC to spend and the smallest TSRA output you will accept. The following example spends 10 EURC and requires at least 1 TSRA. It reverts if the curve cannot satisfy that minimum; these amounts are an example budget, not a quoted exchange rate or a guarantee of how many operations you can run.

Terminal window
npx tsx fund-slot.ts .tasra/first-slot buy 10000000 1000000000000000000

Internally the command uses two confirmed SDK calls:

await writer.approveEurcForCurve(eurcAmount)
await writer.buyTsra(eurcAmount, minimumTsraOut)

Success: an approval hash, purchase hash and updated wallet TSRA balance. Buying TSRA does not automatically credit a slot.

4. Deposit TSRA into the slot

Section titled “4. Deposit TSRA into the slot”

This example deposits 1 TSRA from your saved creator wallet:

Terminal window
npx tsx fund-slot.ts .tasra/first-slot fund 1000000000000000000
npx tsx fund-slot.ts .tasra/first-slot status

The SDK approves Settlement and confirms the deposit:

const {fundTx} = await writer.fundSlot(slotId, slotCredits)
console.log('Funding transaction:', fundTx)
console.log('Slot credit:', await writer.settlementBalance(slotId))

Success: a funding transaction hash and nonzero slot TSRA credit. Usage consumes credit; top up according to the selected network’s charges. A positive balance alone does not guarantee sufficient credit for every operation.

All command amounts are integer base units: EURC has 6 decimals and TSRA has 18. The output labels these units. No extra token or wallet library is needed.

Several slots, transaction retries and recovery

Fund each slot separately. Add --slot with the ID printed by your application:

Terminal window
npx tsx fund-slot.ts .tasra/first-slot status --slot YOUR_PRINTED_SLOT_ID
npx tsx fund-slot.ts .tasra/first-slot fund 1000000000000000000 --slot YOUR_PRINTED_SLOT_ID

Replace YOUR_PRINTED_SLOT_ID with the full 0x slot ID. The command checks that the slot exists and is not cancelled before depositing. Keep the original network manifest; a different snapshot is rejected for this saved state.

Each explicit buy, mint-test-eurc or fund invocation submits new transactions. It is not a resumable payment journal. After a timeout or uncertain result, inspect the recorded transaction and balances before deciding what to do next. Do not blindly repeat a purchase or deposit. A confirmed approval may remain even if its following purchase or deposit fails.

Next: Read your slot →