When developers and AI agents need real-time onchain data, the traditional model — monthly subscriptions, API key approvals, upfront commitments — creates unnecessary friction. Nansen built around that friction entirely.

Nansen was among the first major onchain analytics platforms to go live on x402, letting developers and autonomous agents query wallet data, Smart Money flows, token screeners, and more with a single USDC payment per call. No subscription required. No approval gate. Just fund a wallet and start querying.

The Problem with Subscriptions for Builders

Most onchain data providers still require you to sign up, get approved, and commit to a monthly plan before you run a single query.

That model works for teams with predictable usage. It breaks down for:

• AI Agents that query on-demand and go dormant between runs

• Developers prototyping before they know their actual usage

• Researchers who need a burst of data once, not an ongoing feed

The cost model is also misaligned: you pay the same monthly rate whether you query 10 times or 10,000.

What is x402?

x402 is an open payment protocol built on top of HTTP. When a client requests a paid resource, the server returns a `402 Payment Required` response with a payment specification. The client pays onchain (in USDC), attaches the receipt to the next request, and gets the data back.

The full flow in four steps:

1. Client sends a request to a paid endpoint

2. Server returns a `402` with amount, asset, and network details

3. Client makes the USDC payment and sends it to the server

4. Server settles payment and returns the data

x402 is natively programmable. AI agents can handle the entire payment loop autonomously, with no human in the loop. Coinbase's CDP, PayAI, and multiple other infrastructure providers have committed to supporting x402 as a standard for agent-native API monetization.

What Nansen Built on x402

Nansen's x402 integration covers two pricing tiers across its full API surface. Payments are accepted in USDC on Base or Solana.

Basic Tier: $0.01 per call

Foundational onchain data. High-frequency, agent-friendly.

• Token Screener

• Wallet Balances (current + historical)

• Transactions

• Transfers

• DEX Trades

• PnL Summary

• Flow Intelligence

• DCAs

• Perp Trades + Positions + Screener

• Who Bought/Sold

• Related Wallets

Premium Tier: $0.05 per call

Proprietary, alpha-generating data. The signal layer.

• Smart Money Net Flows

• Smart Money Holdings

• Smart Money DEX Trades

• Smart Money Inflows

• Holders

• Counterparties

• PnL Leaderboard

• Perp PnL Leaderboard

• Perp Leaderboard

To start without a subscription: fund a wallet with USDC on Base or Solana, then query immediately. No API key required.

# Install

npm install -g nansen-cli

# Add the agent skill (for Claude Code, Codex, OpenClaw, etc.)

npx skills add nansen-ai/nansen-cli

# Query Smart Money token flows — $0.05 via x402

nansen smart-money token-flows --token 0xYOUR_TOKEN_ADDRESS

Full endpoint reference and real-world agent workflows (with per-run cost estimates): agents.nansen.ai

Why PayAI for Solana x402

Nansen's x402 integration accepts USDC on both Base and Solana. For Solana-native builders and agents, PayAI provides the facilitator layer that makes this seamless.

PayAI's x402 facilitator offers:

• Gasless transactions — no SOL required for the buyer or merchant. Fees are covered by the facilitator.

• Multi-network in one endpoint — PayAI supports Solana and EVM chains through a single drop-in integration, so you're not managing separate payment paths per chain.

• SDKs for TypeScript, Python, and Rust — standard x402 interfaces, no custom protocol work required.

• 10,000 free settlements — enough to build and test a full agent integration before paying anything.

For Solana-native AI agents querying Nansen, PayAI eliminates the last remaining friction point: the agent doesn't need SOL, doesn't need to manage gas, and doesn't need a separate payment integration for each chain.

What You Can Build

Real workflows running today, with estimated x402 cost per run using Nansen data:

Smart Money Signal Alert — detect when labeled wallets start accumulating a token before the crowd catches on:

• smart-money/dex-trades + smart-money/netflows + smart-money/perp-trades

• ~$0.15 per run

Wallet Due Diligence — full profile on any wallet before copy-trading: PnL history, transaction patterns, counterparties

• profiler/pnl-summary + profiler/transactions + profiler/counterparties

• ~$0.07 per wallet

Token Research Assistant — screen for tokens with Smart Money momentum, check holder distribution, flag early moves

• token-screener + tgm/holders + tgm/flow-intelligence

• ~$0.07 per token

For developers already on Nansen Pro, x402 is an additional access path, existing API key usage still counts toward monthly credits. x402 is for when you want to move faster or build something that pays as it runs.

Why This Matters

The shift from subscription APIs to per-call, agent-native payments is structural. AI agents don't have credit cards. They don't sign up for SaaS plans. They transact onchain.

x402 is the protocol that makes API access a programmable transaction, and Nansen being live on it means any autonomous agent can query 500M+ labeled wallets, Smart Money flows, and token screeners without a human ever approving a subscription.

PayAI's facilitator support for Solana closes the loop for the largest non-EVM ecosystem. Builders who want to ship faster, agents that need to operate autonomously, and protocols that want data without overhead, this is the path.

Get Started

• Nansen x402 endpoints + agent use cases: agents.nansen.ai

• Nansen API docs: docs.nansen.ai

• PayAI x402 facilitator: facilitator.payai.network

• PayAI docs: docs.payai.network