payment-ready until 2026-09-21
API-first email inboxes for AI agents. Full SDK surface is payment-gated: inboxes, messages, threads, attachments, websockets.
Pay from $2.00 in USDC on Avalanche / Base / Polygon / Solana, settled onchain via the x402 protocol, no signup, no API key needed.
measured since 2026-01-30 (start of our harvest window) · $787.77 all-time · settled via payAI
VERDICT
ranking generation 3solid 81/100 #70 of 114 in AI by measured score
What the score read on this service: status online, 99.4% uptime 30d, 1871ms response p95, x402 compliance 14 of 14, $2 price against the category, on-chain traction measured. Each of those is measured, and each is published in full below.
The score comes from our own monitoring, never from reviews, operator claims, or a language model: reliability, x402 compliance, price against the category, a deterministic risk flag, and a small on-chain traction term, weighted by ranking generation 3. It is not placement anyone can buy: the paid verify tier is reported beside it and is not one of its inputs. Every component below stays published and read-only.
It is a score inside AI, and only there: price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, which here means 114 listings, this one among them. That set is wider than the 114 the position above is counted against, because a listing we have measured too little of to rank still sits in the field the price and the speed are normalized over. The same service in a different field would read differently. The same engine answers GET /api/v1/best, and asked for a different pool (the whole directory, or another filter) it returns a different number for this service under this same ranking generation. Neither is more correct: they answer different questions, and the methodology states which is which.
Bands on the 0 to 100 measured score: strong at 93 and above, solid from 75, mixed from 55, weak below 55. Price and speed are scored against the whole category field, every listing in it that carries no danger flag, the scored service included, so the score places a service in its own field.
ALTERNATIVES IN AI
Other AI services in this directory, ordered by the same measured score. The figures are ours: 30-day uptime from our own probes, 30-day settlement volume read on-chain (a conservative undercount, and null where we cannot measure it, never a zero).
| SERVICE | BAND | SCORE | UPTIME 30D | VOL 30D |
|---|---|---|---|---|
| Otto AI | strong | 95 | 100% | $61.64 |
| x402engine | strong | 93 | 100% | $27.16 |
| Agent402.tools | solid | 92 | 98.8% | $136.08 |
| StableEmail | solid | 89 | 100% | $27.48 |
| Exa | solid | 89 | 100% | $45.99 |
ASSESSMENT
updated 2h agoThe parts the verdict above is computed from, each with its proof. Click any chip. Measured values stay read-only; unknown is honest, and an unknown is never counted as a zero.
reliability 99.4%
- uptime 24h
- 93.5%
- uptime 7d
- 99.3%
- uptime 30d
- 99.4%
- uptime 90d
- 99.8%
- response p95
- 1871ms
- avg response
- 1138ms
- total checks
- 7,181
Measured on the unpaid 402 handshake, not the paid call. A service can 402 correctly and still fail after payment.
compliance A (14/14)
14 of 14 x402 conformance checks pass. Full checklist below.
price $2.00 (p94 in AI)
- price (min)
- $2.00
- category percentile (min)
- p94 in AI
- endpoints / prices
- 1 / 1
- model
- flat
- stability
- 100%
risk clean
No deterministic risk flag. Risk fires only on an exact blocklist match, or a reserved-brand name with a mismatched verified payTo. Never from low uptime, a high price, or a model guess.
- domain age
- 622d
- registrar
- NAMECHEAP
- hosting
- custom
- domain created
- 2024-12-25
Identity facts, not a risk score.
traction $86.20 30d · 15 buyers
- volume 30d
- $86.20
- buyers 30d
- 15
- settlements 30d
- 262
- measured since
- 2026-01-30 (start of our harvest window)
- last settlement
- 2026-09-13
- top buyer share
- 37% of 30d volume
- trend 7d vs 30d
- 0.70x the 30d daily rate
- networks
- eip155:137, eip155:8453, solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdpKuc147dw2N9d
- volume all-time
- $787.77
- settlements all-time
- 2,981
- median settlement 30d
- $0.01
- max settlement 30d
- $2.00
- settled via
- payAI ($86.20, 262 tx)
Conservative undercount: only USDC settlements via facilitators we measure are counted. A measured floor, not an estimate.
Top buyer share is a concentration signal, not part of the ranking score.
WHAT IT DOES
ai-derivedProvides email inbox management services with API endpoints for creating, listing, and managing inboxes, pods, drafts, domains, and webhooks.
- category
- email-api
- in
- body
AI-generated summary. The measured data is never altered by it.
ENDPOINTS
| METHOD | PATH | DESCRIPTION | PRICE | NETWORK | ASSET | 402 CHANNEL |
|---|---|---|---|---|---|---|
| POST | /v0/inboxes | Create an inbox | $2.00 | Avalanche/Base/Polygon/Solana | USDC | header |
REQUEST / RESPONSE EXAMPLE
An unpaid request to POST /v0/inboxes returns HTTP 402 with the payment terms. Settle onchain via your facilitator, then retry with the X-Payment header.
curl -i -X POST 'https://x402.api.agentmail.to/v0/inboxes'
// 402 response (captured by monitor) · 1 payload · click to expand
[
{
"error": "Payment required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x6e3184C204e596dED89E8A5693B602097F4Ab687",
"amount": "2000000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 300
},
{
"asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
"extra": {
"feePayer": "2wKupLR9q6wXYppw8Gr2NvWxKBUqm4PPJKkQfoxHDBg4"
},
"payTo": "7r4e5dwNS68MDaxbw7N8jbzHq7RCMBp9z6smHFH4NXWw",
"amount": "2000000",
"scheme": "exact",
"network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
"maxTimeoutSeconds": 300
},
{
"asset": "0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x6e3184C204e596dED89E8A5693B602097F4Ab687",
"amount": "2000000",
"scheme": "exact",
"network": "eip155:43114",
"maxTimeoutSeconds": 300
},
{
"asset": "0x74b7f16337b8972027f6196a17a631ac6de26d22",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x6e3184C204e596dED89E8A5693B602097F4Ab687",
"amount": "2000000",
"scheme": "exact",
"network": "eip155:196",
"maxTimeoutSeconds": 300
},
{
"asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
"extra": {
"name": "USD Coin",
"version": "2"
},
"payTo": "0x6e3184C204e596dED89E8A5693B602097F4Ab687",
"amount": "2000000",
"scheme": "exact",
"network": "eip155:137",
"maxTimeoutSeconds": 300
}
],
"resource": {
"url": "https://api.paysponge.com/v0/inboxes",
"mimeType": "application/json",
"description": "Service: AgentMail API (https://api.paysponge.com/v0/inboxes)"
},
"extensions": {
"bazaar": {
"info": {
"input": {
"body": {
"domain": "<domain>",
"username": "<username>",
"client_id": "<client_id>",
"display_name": "<display_name>"
},
"type": "http",
"method": "POST",
"bodyType": "json"
},
"output": {
"type": "json",
"example": {}
}
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method",
"bodyType",
"body"
],
"properties": {
"body": {
"type": "object",
"title": "CreateInboxRequest",
"properties": {
"domain": {
"type": "string",
"description": "Domain of address. Must be verified domain. Defaults to `agentmail.to`."
},
"username": {
"type": "string",
"description": "Username of address. Randomly generated if not specified."
},
"client_id": {
"type": "string",
"title": "ClientId",
"description": "Client ID of inbox."
},
"display_name": {
"type": "string",
"title": "DisplayName",
"description": "Display name: `Display Name <[email protected]>`."
}
}
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"enum": [
"POST",
"PUT",
"PATCH"
],
"type": "string"
},
"bodyType": {
"enum": [
"json",
"form-data",
"text"
],
"type": "string"
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string",
"const": "json"
},
"example": {
"type": "object",
"additionalProperties": true
}
},
"additionalProperties": false
}
},
"additionalProperties": false
}
}
},
"x402Version": 2
}
] OVER TIME
All charts use the 30d selector; each series spans only the dates it has data for. Every series is also served as JSON at /api/v1/services/agentmail/price, /scores, /volume and /buyers. On-chain volume and distinct buyers are measured over the service's settlement address and are a conservative undercount (only settlements that reach a measured facilitator are counted). The on-chain series roll up hourly, so the latest day can be up to about an hour behind; distinct buyers are counted per payout address, so a service that settles to more than one address is an upper bound.
checklist grew 11->14 on 2026-07-28; a step here is a metric change, not a regression
Measured site and economics pillars from the assessment history, so the latest value shown elsewhere on this page reads as a point on a trend rather than a permanent state.
COMPLIANCE
14/14 checks pass · grade Alast 402 captured 2026-07-20 · last up 2026-09-14
- 402 payload captured
- accepts[] array present
- payTo address recoverable
- payTo at accepts[0].payTo (conformant shape)
- payTo is a valid on-chain address
- atomic price declared
- atomic price in a sane range
- asset (token) address declared
- network resolves to CAIP-2
- payment scheme declared
- served over HTTPS
- declares the current x402 version (2)
- EIP-712 domain parameters present on every EVM entry
- x402 v2 envelope delivered in the payment-required header
SITE PILLARS
- homepage reachable
- openapi doc
- pricing page
- llms.txt
- robots.txt
- terms page
recent checks (18) live · click to expand
EMBED THIS BADGE
<a href="https://x402-list.com/services/agentmail?utm_source=badge&utm_medium=referral&utm_campaign=embed"> <img src="https://x402-list.com/badge/agentmail.svg" alt="AgentMail listed on x402-list" height="28"> </a>
[](https://x402-list.com/services/agentmail?utm_source=badge&utm_medium=referral&utm_campaign=embed)
<a href="https://x402-list.com/services/agentmail?utm_source=badge&utm_medium=referral&utm_campaign=embed"> <img src="https://x402-list.com/badge/agentmail.svg?data=uptime" alt="AgentMail uptime on x402-list" height="28"> </a>