nansen-mpp-payment

MPP / Tempo

The Nansen API supports three paid-access rails: API key, x402 (handled by nansen-cli), and MPP via Tempo (handled by the separate tempo CLI). This skill covers the third.

nansen-cli does not sign MPP credentials. Use this skill when the user wants to call the Nansen API through tempo request because they already use tempo, want micropayments without managing wallet keys themselves, or don't want to fund a Base/Solana USDC wallet.

For API-key auth, see nansen-wallet-manager. For x402 micropayment with a local wallet, see nansen-trading / nansen-wallet-manager.

When to use this skill

• User says "MPP", "tempo", "Authorization: Payment", or "Payment-Receipt".
• User has no Nansen API key and doesn't want to set up a Base/Solana wallet.
• User is already paying for other APIs through tempo and wants Nansen on the same rail.

One-time setup

# 1. Install the tempo CLI
curl -fsSL https://tempo.xyz/install | bash
# 2. Log in (creates / unlocks the tempo wallet)
tempo wallet login
# 3. Fund it with USDC on the chain tempo selects for your environment
tempo wallet fund
# 4. Confirm the wallet is ready
tempo wallet whoami

Calling the Nansen API

tempo request handles the full MPP challenge/response: it sends the request, signs the Authorization: Payment credential when the API responds 402 + WWW-Authenticate: Payment ..., retries, and exposes the Payment-Receipt header on success.

# Smart Money netflow
tempo request POST https://api.nansen.ai/api/v1/smart-money/netflow \
  --json '{"chains":["solana"],"pagination":{"page":1,"page_size":10}}'

# TGM holders
tempo request POST https://api.nansen.ai/api/v1/tgm/holders \
  --json '{"token_address":"EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v","chain":"solana"}'

Endpoint paths and request shapes are the same as the rest of the Nansen API — run nansen schema <command> (no API key required) to look up the body shape, then call the matching /api/v1/... path through tempo request.

Discovering paid endpoints

curl https://api.nansen.ai/.well-known/x402

Returns paymentProtocols: ["x402", "mpp"] (when MPP is enabled server-side) and the list of paid resources.

How MPP differs from x402

| | x402 (nansen-cli native) | MPP via tempo (this skill) |

|---|---|---|

| Header sent on retry | Payment-Signature: <base64> | Authorization: Payment <credential> |

| 402 challenge header | Payment-Required: <base64> | WWW-Authenticate: Payment ... |

| Success header | _(none)_ | Payment-Receipt: <base64> |

| Wallet | local, Privy, or WalletConnect — managed by nansen-cli | tempo-managed (separate CLI) |

| Chains | Base USDC, Solana SPL USDC, X Layer USDT0 | Tempo's chain (mainnet USDC in prod, moderato pathUSD in dev) |

| nansen-cli code path | src/x402.js auto-signs on 402 | not handled — call via tempo request directly |

Notes

• MPP is server-side opt-in. If tempo request returns a 402 without WWW-Authenticate: Payment, MPP isn't enabled for that endpoint/environment — fall back to an API key or x402.
• Don't try to add --mpp-* flags to nansen-cli — the supported integration is "use tempo separately". If the user asks for tighter integration, point them at this skill and confirm the requirement before adding code.
• Per-request price is the same as x402 (1 credit ≈ $0.001 with 10x markup, e.g. 1-credit endpoints cost $0.01).

Source

• npm: https://www.npmjs.com/package/nansen-cli
• GitHub: https://github.com/nansen-ai/nansen-cli
• MPP protocol: https://mpp.dev/protocol
• Tempo docs: https://docs.tempo.xyz