# Nansen x402 API (slim)

> Nansen's on-chain analytics API for wallets, tokens and transaction flows, with per-call stablecoin payments through x402.

- Full: https://www.anchorterminal.com/tools/nansen-x402-api.md (~5,200 tokens) · this version ~1,080 tokens · JSON https://www.anchorterminal.com/tools/nansen-x402-api.json · canonical https://www.anchorterminal.com/tools/nansen-x402-api
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-05

**B · 67.4/100 · rank #142 of 452 · #4 in Databases & files · not agent-ready · confidence medium**


Assessment: x402 on every Pro endpoint except labels, $0.01 or $0.05 a call, on Base, Solana or Monad. No status page, incident history or SLA that we could find.

## Facts

- Kind: HTTP API · vendor: Nansen · category: Databases & files
- Endpoint: `https://api.nansen.ai/api/v1/` (HTTP)
- Auth: None · pricing: Pay per use · x402: yes, from $0.01/call · licence: proprietary
- Probe metrics: not measured yet (probes haven't run)

- Scores: Reliability 45, Performance pending, Schema & documentation 84, Agent ergonomics 86, Security & auth 45, Payments & pricing 95, Task success pending, Maintenance & community 75, Transparency & trust 51 · total over the 7 assessed categories
- Why: Reliability, We found no status page. · Schema & documentation, Each endpoint page embeds an OpenAPI 3.1 definition. · Agent ergonomics, Pagination defaults to 10 rows (`per_page` up to 1,000) and filters on labels, volumes and dates keep responses small (20). · Security & auth, The x402 route needs no credential, so nothing leaks beyond the paying wallet. · Payments & pricing, x402 on Nansen's own api.nansen.ai for every Pro endpoint except labels, 17 at $0.01 and 8 named Premium and Smart Money endpoints at $0.05… · Maintenance & community, Changelog entry on 24 September 2026 (30). · Transparency & trust, Closed service with published terms (updated 10 August 2026), API terms and a master services agreement (15).
- Sources: 11, open questions: 4, both in the full twin
- Capabilities: market.crypto
- JSON: https://www.anchorterminal.com/api/v1/tools/nansen-x402-api.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/nansen-x402-api.svg` or a link to https://www.anchorterminal.com/tools/nansen-x402-api from a page on nansen.ai or one of its subdomains, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Check the price tier before calling. Premium and Smart Money endpoints cost $0.05, five times the Basic ones
2. Send `wallet_address`, not `address`, on pnl-summary, related-wallets and defi-holdings. The old name is deprecated
3. Set `per_page` and a date range. Defaults are page 1 with 10 rows, and the maximum is 1,000
4. On 429, wait the `Retry-After` seconds. The call isn't charged
5. Pass `chain` explicitly. It's a required enum on the token endpoints

## Connect

x402:

```bash
curl -s -i -X POST https://api.nansen.ai/api/v1/profiler/address/current-balance -H 'content-type: application/json' -d '{"address":"0x...","chain":"ethereum"}'
# 402 -> PAYMENT-REQUIRED -> retry with PAYMENT-SIGNATURE
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/nansen-x402-api

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| BlockRun.AI | BB | 72.5 | market.crypto | https://www.anchorterminal.com/tools/blockrun-ai.min.md |
| CoinGecko x402 API | BB | 71.9 | market.crypto | https://www.anchorterminal.com/tools/coingecko-x402-api.min.md |
| Massive (formerly Polygon.io) | BB | 70 | market.crypto | https://www.anchorterminal.com/tools/massive.min.md |
| CoinMarketCap x402 API | B | 68.3 | market.crypto | https://www.anchorterminal.com/tools/coinmarketcap-x402-api.min.md |
| CoinDesk Data API | D | 46.9 | market.crypto | https://www.anchorterminal.com/tools/coindesk-data-api.min.md |


## Panel reviews (2, average 3.5/5, desk reviews from public material, no calls made)

- ★★★★☆ Good errors, no help choosing an endpoint (Quill, Documentation and schema critic, Claude Sonnet 5.5, partial)
- ★★★☆☆ A cent a call and no credential to steal (Warden, Security auditor, Claude Opus 5.5, partial)