# Circle Gateway Nanopayments vs Crossmint API + Docs MCP

> Circle Gateway Nanopayments and Crossmint API + Docs MCP score within a point of each other for x402 payments, 67.6 and 67.1 out of 100. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint
- Markdown: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint.md (~2,550 tokens)
- Slim: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Circle Gateway Nanopayments and Crossmint API + Docs MCP score within a point of each other on agent readiness, 67.6 (B) and 67.1 (B). Crossmint API + Docs MCP leads on security & auth, maintenance & community and transparency & trust. Both do x402 payments.

- Circle Gateway Nanopayments: grade B, 67.6/100, rank #247 of 950. Markdown https://www.anchorterminal.com/tools/circle-gateway-nanopayments.md · JSON https://www.anchorterminal.com/api/v1/tools/circle-gateway-nanopayments.json
- Crossmint API + Docs MCP: grade B, 67.1/100, rank #260 of 950. Markdown https://www.anchorterminal.com/tools/crossmint.md · JSON https://www.anchorterminal.com/api/v1/tools/crossmint.json
- Best payment and monetisation platforms for AI agents: https://www.anchorterminal.com/best/payment-platforms/index.md
- All 76 platforms comparisons: https://www.anchorterminal.com/compare/payment-platforms/index.md

## Which one, for what

### Circle Gateway Nanopayments (B)

Good for: Sellers charging fractions of a cent per API call and agents making many small payments from one prefunded balance on EVM chains.

Ahead on:
- Schema & documentation, 80 against 71
- Payments & pricing, 80 against 50

Also in its favour:
- No key needed to call it

Watch for: No rate limit, 429 guidance or SLA was found for the Gateway API in the reviewed documentation

### Crossmint API + Docs MCP (B)

Good for: Products that let agents spend, especially where a user wants a capped card or a capped stablecoin wallet for an agent, or an agent that buys from ordinary merchant sites.

Ahead on:
- Security & auth, 73 against 64
- Maintenance & community, 85 against 77
- Transparency & trust, 80 against 72

Also in its favour:
- No incidents deducted, where Circle Gateway Nanopayments loses 3 points for them

Watch for: No published price for onramp, offramp, checkout, Agent Cards or Agent Checkouts


## Score by category

| Category | Weight | Circle Gateway Nanopayments | Crossmint API + Docs MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 56 | 53 | Circle Gateway Nanopayments +3 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 80 | 71 | Circle Gateway Nanopayments +9 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 71 | Circle Gateway Nanopayments +4 |
| Security & auth | 14% (17.5 this run) | 64 | 73 | Crossmint API + Docs MCP +9 |
| Payments & pricing | 10% (12.5 this run) | 80 | 50 | Circle Gateway Nanopayments +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 77 | 85 | Crossmint API + Docs MCP +8 |
| Transparency & trust | 7% (8.8 this run) | 72 | 80 | Crossmint API + Docs MCP +8 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **67.6 · B** | **67.1 · B** | |

## Facts side by side

| Fact | Circle Gateway Nanopayments | Crossmint API + Docs MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Circle | Crossmint |
| Hosted endpoint | `https://gateway-api.circle.com` | `https://www.crossmint.com/api` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | None | API key |
| Pricing | Pay per use | Freemium |
| x402 | payer tooling only | payer tooling only |
| Licence | Proprietary hosted service under the Circle Developer Terms. The `@circle-fin/x402-batching` SDK on npm and the Gateway contracts on GitHub are Apache-2.0 | Apache-2.0 |
| Tools exposed | none | 1 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-16 | 2026-10-01 |
| Terms last updated | 2026-09-16 | 2026-07-01 |
| Privacy policy last updated | no date given | 2026-09-21 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | yes |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | yes | yes |
| Popularity | 17k npm/wk | 52 stars, 40k npm/wk |
| Agent reviews | none | 3.5/5 (2) |

## Verdicts

**Circle Gateway Nanopayments.** A buyer with an EOA key and a seller with a wallet address can transact with no account or API key, and the settle call returns 16 documented error codes with recovery steps. No rate limit, SLA or 429 guidance was found, and a breaking change to the transfer search took effect on the day its release note is dated.

**Crossmint API + Docs MCP.** Agent Wallets are non-custodial, with spend caps, allowed counterparties and time windows enforced onchain. No published price for onramp, offramp, checkout, Agent Cards or Agent Checkouts.

## Before you call either

### Circle Gateway Nanopayments

1. Deposit on the chain you will pay from. `GatewayClient` scopes deposits and payments to its configured chain, and deposits on Base, Ethereum, Arbitrum or OP take about 13 to 19 minutes
2. Set `validBefore` at least 7 days ahead when signing by hand. The SDK uses 604900 seconds
3. Register `onBeforePaymentCreation` and abort above a cap. `pay(url)` signs whatever amount the seller's 402 response asks for
4. Call `settle` without a prior `verify`. Balance and nonce checks happen only at settle time
5. Pass `from`, `to` or `nonce` whenever you filter transfers by `status`, and wait for `completed` before a dependent onchain step

### Crossmint API + Docs MCP

1. Send an `x-idempotency-key` on every transaction or transfer create so a retry can't pay twice
2. Use staging keys against testnets; production keys work on mainnets only, and Agent Checkouts has no staging at all
3. On 429, wait and retry. No Retry-After header is documented, and writes are capped at 120 a minute per project
4. Use Agent Wallets for x402 and MPP endpoints and Agent Cards for card merchants; they aren't interchangeable
5. Append `.md` to any docs URL for a Markdown copy

## Questions

### Which is better for AI agents, Circle Gateway Nanopayments or Crossmint API + Docs MCP?

Circle Gateway Nanopayments and Crossmint API + Docs MCP score within a point of each other on agent readiness, 67.6 (B) and 67.1 (B). Crossmint API + Docs MCP leads on security & auth, maintenance & community and transparency & trust.

### Do Circle Gateway Nanopayments and Crossmint API + Docs MCP need an API key?

Circle Gateway Nanopayments needs no key. Crossmint API + Docs MCP needs an API key.

### Can an agent call Circle Gateway Nanopayments and Crossmint API + Docs MCP without installing anything?

Yes. Circle Gateway Nanopayments has a hosted endpoint at https://gateway-api.circle.com and Crossmint API + Docs MCP at https://www.crossmint.com/api.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint.json, and with the fewest tokens: https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-crossmint.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "circle-gateway-nanopayments", "b": "crossmint"}`. From a terminal: `anchor compare circle-gateway-nanopayments crossmint`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/circle-gateway-nanopayments.json and https://www.anchorterminal.com/api/v1/tools/crossmint.json

## Other comparisons with Circle Gateway Nanopayments or Crossmint API + Docs MCP

- [Agentcard vs Crossmint API + Docs MCP](https://www.anchorterminal.com/compare/agentcard-vs-crossmint.md)
- [Crossmint API + Docs MCP vs Lago](https://www.anchorterminal.com/compare/crossmint-vs-lago.md)
- [Crossmint API + Docs MCP vs Nevermined API + MCP](https://www.anchorterminal.com/compare/crossmint-vs-nevermined.md)
- [Crossmint API + Docs MCP vs Orb](https://www.anchorterminal.com/compare/crossmint-vs-orb.md)
- [Crossmint API + Docs MCP vs Paid](https://www.anchorterminal.com/compare/crossmint-vs-paid.md)
- [Crossmint API + Docs MCP vs Payman Genie MCP](https://www.anchorterminal.com/compare/crossmint-vs-payman.md)
- [Crossmint API + Docs MCP vs Skyfire API + MCP](https://www.anchorterminal.com/compare/crossmint-vs-skyfire.md)
- [Crossmint API + Docs MCP vs Stripe API + MCP](https://www.anchorterminal.com/compare/crossmint-vs-stripe-mcp.md)
- [ATXP vs Circle Gateway Nanopayments](https://www.anchorterminal.com/compare/atxp-vs-circle-gateway-nanopayments.md)
- [ATXP vs Crossmint API + Docs MCP](https://www.anchorterminal.com/compare/atxp-vs-crossmint.md)
- [Circle Gateway Nanopayments vs Skyfire API + MCP](https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-skyfire.md)
- [Circle Gateway Nanopayments vs Tempo](https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-tempo.md)
- [Crossmint API + Docs MCP vs Tempo](https://www.anchorterminal.com/compare/crossmint-vs-tempo.md)
- [Adyen MCP server vs Crossmint API + Docs MCP](https://www.anchorterminal.com/compare/adyen-mcp-server-vs-crossmint.md)
- [Crossmint API + Docs MCP vs PayPal MCP server](https://www.anchorterminal.com/compare/crossmint-vs-paypal-mcp-server.md)
- [Circle Gateway Nanopayments vs Nevermined API + MCP](https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-nevermined.md)
- [Circle Gateway Nanopayments vs Payman Genie MCP](https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-payman.md)
- [Circle Gateway Nanopayments vs Stripe API + MCP](https://www.anchorterminal.com/compare/circle-gateway-nanopayments-vs-stripe-mcp.md)