feedback.send

Send a message straight to the 2s team. POST { message } (required) plus optional subject, name, and from (your email — set as the reply-to + shown as the sender so the team can get back to you). Delivers your message by email to the 2s maintainers — use it for feedback, bug reports, endpoint requests, or to get in touch. Flat $0.10 per send; the payment keeps the channel spam-free. The recipient is fixed (the 2s team), so this is a one-way contact channel, not a general mailer. Returns { sent, id }. Trial calls are not accepted — this endpoint always requires payment.

price
$0.1000 USDC per call
method
POST/api/feedback/send
payment
x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)
auth
None. Sign the payment, retry with PAYMENT-SIGNATURE.
tier
Tier 0 — no paid upstream

Overview

The send API is a pay-per-call feedback endpoint built for AI agents and autonomous software. Send a message straight to the 2s team.

There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in send data source for an agent tool-use loop, an MCP host, or a backend that needs feedback data on demand without onboarding to yet another vendor portal.

Use cases

Parameters

NameTypeDescription
messagerequiredstringMessage body to send to the 2s team.
min 1 chars · max 5000 chars
subjectstringOptional subject line.
max 200 chars
namestringOptional name to attribute the message to.
max 120 chars
fromstringYour email — set as reply-to + shown as the sender.
max 254 chars · email

Code samples

cURLbash
# 1. Probe the endpoint with no auth — receive 402 with PaymentRequirements
curl -sS -X POST 'https://2s.io/api/feedback/send' \
  -H 'Content-Type: application/json' \
  -d '{"message":"example","subject":"example","name":"example","from":"user@example.com"}'

# 2. Sign the EIP-3009 transferWithAuthorization for the advertised price +
#    payTo from the 402 envelope, then retry with PAYMENT-SIGNATURE:
curl -sS -X POST 'https://2s.io/api/feedback/send' \
  -H 'Content-Type: application/json' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>' \
  -d '{"message":"example","subject":"example","name":"example","from":"user@example.com"}'

# Or just use the canonical runner — it handles the whole loop:
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/feedback/send'
TypeScript / Node — @2sio/sdktypescript
import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.feedback.send({
  "message": "example",
  "subject": "example",
  "name": "example",
  "from": "user@example.com"
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)
Python — 2siopython
import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.feedback.send(message="example", subject="example", name="example", from="user@example.com")

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)
MCP — Claude Desktop / AgentKit / any MCP hostjson
// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "feedback.send",
    "arguments": {
      "message": "example",
      "subject": "example",
      "name": "example",
      "from": "user@example.com"
    }
  }
}

Response

FieldTypeDescription
okboolean
one of: true
itemsarray
totalintegerTotal matching rows upstream; null when unknown.
sourceobject
metaobject
Example response datajson
{
  "ok": true,
  "items": [
    {
      "sent": false,
      "id": "example",
      "recipient": "example"
    }
  ],
  "total": 1,
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  },
  "meta": {}
}

FAQ

Do I need an API key to use the send API?
No. feedback.send is x402-native — there is no signup and no API key. Your client makes the call, receives a 402 with payment requirements, signs a USDC payment, and retries. Funds come from a wallet you control.
How much does the send API cost?
$0.1000 USDC per call, charged per request. There are no monthly fees, seats, or minimums — you pay only for the calls you make.
Can I try the send API for free first?
Yes. Add ?trial=1 (or the header X-2s-Trial: 1) to get a free real call per endpoint per hour, so you can verify the response shape before wiring payment.
Which networks and tokens are supported?
USDC on Base (via EIP-3009 transferWithAuthorization) or Solana (SPL transfer), using the open x402 payment protocol.
How do I call feedback.send from an AI agent or MCP host?
Use @2sio/sdk (TypeScript), 2sio (Python), or the @2sio/mcp server for any MCP host — each handles the probe → sign → retry loop for you. See the code samples on this page.

Discovery

Related: send api · feedback send api · send api for ai agents · x402 feedback api · send api no api key · pay per call send api · feedback api