x420 Whitepaper
Just as x402 standardized payments for autonomous agents via HTTP 402, Calm Your Requests repurposes HTTP 420 Enhance Your Calm to create a credible protocol for graceful rate limiting and throttling. This standard enables AI agents and web services to negotiate cooldown periods automatically.
Fun Fact: Twitter introduced the nonstandard HTTP 420 response in its early API. The phrase comes from the 1993 film Demolition Man.
How It Works
When a client exceeds rate limits, the server responds with HTTP 420 including structured calm instructions:
HTTP/1.1 420 Enhance Your Calm
Content-Type: application/calm+json
Retry-After: 60
{
"retry_after": 60,
"token": "abcd1234efgh5678",
"pow_challenge": null,
"alternativePayment": {
"amount": "0.01",
"currency": "USD"
}
}The client waits or pays, then re-requests with the calm token:
GET /api/resource HTTP/1.1 Host: example.com Calm-Token: abcd1234efgh5678
Calm Your Requests complements x402 by adding a time-based negotiation layer. Together, they let agents choose whether to spend currency or time. Sometimes the optimal solution is to enhance your calm.