Crossmint API + Docs MCP vs Paid

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.

Paid

Paid suits a builder who wants usage metering, credits and invoicing behind one API, with restricted and customer-bound keys, OAuth on the MCP server and a free plan that needs no card. No status page, SLA figure, API changelog or rate-limit numbers were found, both advertised OpenAPI links returned 404, and card payments need the builder's own Stripe account.

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

Paid

1. Call https://api.agentpaid.io/api/v2 with Authorization: Bearer <key>. A person creates the first key at app.paid.ai. No programmatic signup was found
2. Give every signal a stable idempotencyKey and resend the same key on retry. Signals without one are not deduplicated
3. Send at most 500 signals a request. A 429 rejects the whole batch, so wait for Retry-After and resend it all
4. Read the code field on a 429. CONCURRENCY_LIMIT_EXCEEDED carries no Retry-After and clears when an analytics query finishes
5. Install the Python SDK as paid-python, the name in its README and pyproject.toml. The quickstart's pip install paid names a package we could not check