MPP getting started

1. Prerequisites

• Rabby browser extension. Use Rabby, not Coinbase Wallet. Coinbase Wallet's token list does not include Tempo's USDC.e — it will silently show a zero balance after you bridge, and you will lose 30 minutes trying to figure out why. Rabby works.
• ~$5 USDC plus a small amount of ETH on a Stargate-supported L2. Base is recommended (cheapest gas). Arbitrum, Optimism, and Polygon also work.
• Node.js with npx for the mppx CLI. No global install needed.

2. Set up Rabby

Install Rabby and either import an existing seed phrase or create a new wallet. Rabby is open source and has the cleanest UX for unusual chains.

Tempo is not in Rabby's default network list yet, so add it manually under Settings → More → Add custom network:

• Field

  Network name

  Value

  Tempo

• Field

  RPC URL

  Value

  https://rpc.tempo.xyz

• Field

  Chain ID

  Value

  4217

• Field

  Block explorer

  Value

  https://explore.tempo.xyz

• Field

  Native currency symbol

  Value

  —

Tempo has no native gas token — gas is paid in USDC.e via fee abstraction. If Rabby insists on a symbol, leave it blank or use a placeholder.

3. Get USDC.e on Tempo via Stargate

Tempo's USDC.e is bridged-via-Stargate. There is no other route to USDC.e on Tempo today, and there is no Circle-native USDC on Tempo at all. Stargate's Custom Address feature lets you bridge directly to your mppx wallet so you never have to do a Tempo-side transfer (more on why that matters in the pitfalls section).

1. Open stargate.finance/bridge and connect Rabby.
2. From: Base · USDC.
3. To: Tempo · USDC.e.
4. Toggle Custom Address ON and paste your mppx wallet address (you'll get this in the next step — come back here after running npx mppx account list).
5. Bridge. Stargate's fee is ~$0.06 USDC plus a few cents of Base ETH gas.

The bridged tokens land directly in your mppx wallet on Tempo. You do not need to (and currently cannot easily) move them around on Tempo afterward.

4. Create your mppx wallet

The mppx CLI manages a separate wallet — distinct from Rabby — that signs MPP requests on your behalf. The private key is stored locally.

# Create the mppx wallet (one-time)
npx mppx account create

# Show the address
npx mppx account list

The address printed by npx mppx account list is what you paste into Stargate's Custom Address field in step 3. Bridge after creating the wallet, not before — you need the address first.

mppx writes the private key to a local file. Back it up the same way you would any other wallet seed.

5. Make a paid narration request

With the wallet funded, hit the mainnet API. mppx handles the 402 challenge, the on-chain payment in USDC.e, and the credential construction automatically.

npx mppx https://podread.app/api/v1/mpp/narrations \
  -X POST -H "Content-Type: application/json" \
  -d '{"source_type":"text","text":"Hello"}' \
  --rpc-url https://rpc.tempo.xyz

On success the server returns {"id":"nar_..."}. Save that id — you'll use it to fetch the audio in the next step.

6. Retrieve your narration audio

Audio generation is asynchronous — typically 10-30 seconds for short text. Poll the narration endpoint:

curl https://podread.app/api/v1/mpp/narrations/nar_<id> | jq

When status reads complete, the response includes an audio_url field. That URL is a signed download link — open it in a browser, or:

curl -L -o test.mp3 "<audio_url>"

The signed URL expires after 5 minutes. Re-poll GET /api/v1/mpp/narrations/:id for a fresh URL if needed. The narration record itself is kept for 24 hours after creation; after that the GET returns 404.

7. Common pitfalls

• Coinbase Wallet does not support Tempo's USDC.e. The token list silently omits it, so a bridged balance shows as zero. Use Rabby.
• Tempo has no native gas token. Gas is paid in USDC.e via fee abstraction. Rabby's pre-flight gas check still expects a native balance, so a direct Tempo-side ERC-20 send may fail with a "Not enough gas" warning even though the chain itself would accept it. The workaround is what step 3 does — use Stargate's Custom Address feature to deposit directly into the mppx wallet, skipping the Tempo-side transfer entirely. mppx itself signs Tempo transactions correctly.
• Network mismatch when signing. Make sure Rabby's active network (the pill at the bottom of the extension popup) matches what the dapp expects when you click "Bridge" or "Approve". Stargate's source-chain selector and Rabby's active network must agree.

8. Cost breakdown

Approximate, in USD, for a single Standard-tier narration funded fresh from Base:

• Item

  Narration (Standard tier, Tempo)

  Cost

  $0.75 USDC.e

  Notes

  wren, felix, sloane, archer, gemma, hugo, quinn, theo

• Item

  Narration (Premium tier, Tempo)

  Cost

  $2.00 USDC.e

  Notes

  elara, callum, lark, nash

• Item

  Stargate bridge fee

  Cost

  ~$0.06 USDC

  Notes

  Per bridge, regardless of amount

• Item

  Base ETH gas (bridge tx)

  Cost

  ~$0.01 - $0.10

  Notes

  Varies with Base congestion

• Item

  Tempo gas (paid in USDC.e)

  Cost

  ~$0.05

  Notes

  Approximate; mppx pays this for you

Bridging once and making several narrations amortizes the bridge fee. ~$5 USDC is a comfortable starter balance — covers several Standard narrations plus headroom for gas and the bridge round-trip.