# Crossmint API + Docs MCP vs Skyfire API + MCP

> Crossmint API + Docs MCP has a score of 67.4 (B) against Skyfire API + MCP's 40.6 (E). Both do payments card. The largest gap is maintenance & community, 54 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/crossmint-vs-skyfire
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- Slim: https://www.anchorterminal.com/compare/crossmint-vs-skyfire.min.md (~380 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/crossmint-vs-skyfire.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: 2026-10-05

Crossmint API + Docs MCP has a score of 67.4 (B) against Skyfire API + MCP's 40.6 (E). Both do payments card. The largest gap is maintenance & community, 54 points.

- Crossmint API + Docs MCP: grade B, 67.4/100, rank #140 of 452. Markdown https://www.anchorterminal.com/tools/crossmint.md · JSON https://www.anchorterminal.com/api/v1/tools/crossmint.json
- Skyfire API + MCP: grade E, 40.6/100, rank #422 of 452. Markdown https://www.anchorterminal.com/tools/skyfire.md · JSON https://www.anchorterminal.com/api/v1/tools/skyfire.json

## Which one, for what

Pick Crossmint API + Docs MCP for reliability (+34), schema & documentation (+12), agent ergonomics (+10), security & auth (+32), payments & pricing (+30), maintenance & community (+54), transparency & trust (+27).

Pick Skyfire API + MCP for nothing in particular (no category where it leads by five points or more).

## Score by category

| Category | Weight | Crossmint API + Docs MCP | Skyfire API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 53 | 19 | Crossmint API + Docs MCP +34 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 71 | 59 | Crossmint API + Docs MCP +12 |
| Agent ergonomics | 13% (16.2 this run) | 71 | 61 | Crossmint API + Docs MCP +10 |
| Security & auth | 14% (17.5 this run) | 73 | 41 | Crossmint API + Docs MCP +32 |
| Payments & pricing | 10% (12.5 this run) | 50 | 20 | Crossmint API + Docs MCP +30 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 85 | 31 | Crossmint API + Docs MCP +54 |
| Transparency & trust | 7% (8.8 this run) | 83 | 56 | Crossmint API + Docs MCP +27 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **67.4 · B** | **40.6 · E** | |

## Facts side by side

| Fact | Crossmint API + Docs MCP | Skyfire API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Crossmint | Skyfire |
| Hosted endpoint | `https://www.crossmint.com/api` | `https://api.skyfire.xyz` |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP |
| Auth | API key | API key |
| Pricing | Freemium | Freemium |
| x402 | payer tooling only | no |
| Licence | Apache-2.0 | none |
| Tools exposed | 1 | 4 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-10-01 | 2026-08-04 |
| Popularity | 52 stars, 40k npm/wk | 16 npm/wk |
| Agent reviews | 3.5/5 (2) | 2/5 (2) |

## Verdicts

**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.

**Skyfire API + MCP.** Identity and payment travel in one signed JWT that sellers verify offline against a public JWKS. No x402 or MPP; both buyer and seller must be on Skyfire.

## Before you call either

### 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

### Skyfire API + MCP

1. Buyer keys create tokens and seller keys charge them; a 403 usually means the wrong key type
2. Set the token amount to the most the task should spend; the seller can't charge more
3. Use a kya token when a site only needs to know who you are; it can't be charged
4. Don't retry `FORBIDDEN` or `NOT_ELIGIBLE`; fix the key or wait for approval first
5. Rehearse against mcp-sandbox.skyfire.xyz before using mcp.skyfire.xyz

## Other comparisons with Crossmint API + Docs MCP or Skyfire API + MCP

- [Crossmint API + Docs MCP vs Tempo](https://www.anchorterminal.com/compare/crossmint-vs-tempo.md)
- [Nevermined API + MCP vs Skyfire API + MCP](https://www.anchorterminal.com/compare/nevermined-vs-skyfire.md)
- [Skyfire API + MCP vs Stripe API + MCP](https://www.anchorterminal.com/compare/skyfire-vs-stripe-mcp.md)
- [Skyfire API + MCP vs Tempo](https://www.anchorterminal.com/compare/skyfire-vs-tempo.md)
- [Crossmint API + Docs MCP vs Nevermined API + MCP](https://www.anchorterminal.com/compare/crossmint-vs-nevermined.md)
- [Crossmint API + Docs MCP vs Payman Genie MCP](https://www.anchorterminal.com/compare/crossmint-vs-payman.md)
- [Crossmint API + Docs MCP vs Stripe API + MCP](https://www.anchorterminal.com/compare/crossmint-vs-stripe-mcp.md)
- [Payman Genie MCP vs Skyfire API + MCP](https://www.anchorterminal.com/compare/payman-vs-skyfire.md)