Get Email Quote

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: <your_x402_signature>" \
  -d '{
    "from_address": "[email protected]",
    "to_address": "[email protected]",
    "subject": "Hello",
    "body": "Test email"
  }'

const response = await fetch(
  "https://win.oneshotagent.com/v1/tools/email/quote",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-Payment-Proof": paymentProof,
    },
    body: JSON.stringify({
      from_address: "[email protected]",
      to_address: "[email protected]",
      subject: "Hello",
      body: "Test email",
    }),
  },
);

{
  "domain": "yourdomain.com",
  "is_new": true,
  "available": true,
  "registration_fee": 10.0,
  "service_fee": 0.01,
  "mailbox_provisioning_fee": 0,
  "total_cost": 10.01,
  "currency": "USD",
  "quote_id": "quote_abc123",
  "status": "unprovisioned"
}

POST

tools

quote

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: <your_x402_signature>" \
  -d '{
    "from_address": "[email protected]",
    "to_address": "[email protected]",
    "subject": "Hello",
    "body": "Test email"
  }'

const response = await fetch(
  "https://win.oneshotagent.com/v1/tools/email/quote",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-Payment-Proof": paymentProof,
    },
    body: JSON.stringify({
      from_address: "[email protected]",
      to_address: "[email protected]",
      subject: "Hello",
      body: "Test email",
    }),
  },
);

{
  "domain": "yourdomain.com",
  "is_new": true,
  "available": true,
  "registration_fee": 10.0,
  "service_fee": 0.01,
  "mailbox_provisioning_fee": 0,
  "total_cost": 10.01,
  "currency": "USD",
  "quote_id": "quote_abc123",
  "status": "unprovisioned"
}

Authentication

Requires X-Agent-ID header with your wallet address.

Request Body

string

Sender email address (e.g., [email protected]).If omitted, the server picks one from the agent’s domain pool via domain rotation: LRU + per-day capacity + warmup-score gates over every pool_status='active' row the caller owns. The chosen address is echoed back as from_address in the response and locked into the quote — the matching /email/send replays it automatically, so the caller can either omit from_address on send or pass the same value. Passing a different address on send returns 400 from_address_mismatch.If provided, the pool is bypassed and the server only checks domain ownership. Use this when you want to pin sends to a specific mailbox (e.g. [email protected] vs [email protected]).Pinning also bypasses the warmup-score and daily_send_limit gates — those are enforced only during rotation. If the pinned domain is still warming or over its daily cap the send still proceeds, but the response carries a non-blocking warning (pinned_domain_warming / pinned_over_limit). Reputation and limits are per-domain, shared by every mailbox on it, so multiple mailboxes are not a deliverability or capacity lever.

string | string[]

required

Recipient email address(es)

string

required

Email subject line

string

required

Email body content (plain text)

string

How the domain sends: relay (default) or mailbox. mailbox provisions a real dedicated mailbox per address and prices the one-time mailbox_provisioning_fee on this quote; relay is header-only send (fee 0). Only applies when the domain is first set up. See Send for the full semantics — the quote locks the mode in, so omit mailbox_mode on /email/send to replay it.

Response

string

Domain extracted from from_address

boolean

Whether this is a new domain that needs registration

boolean

Whether the domain is available for registration

number

Cost to register the domain (USD)

number

Cost to send the email (USD)

number

One-time fee (USD) charged the first time you send from an address that needs a real mailbox provisioned on the domain — the address is created and warmed on first use. This applies to every address, including the domain’s default sender (default_from); it’s 0 only once that address is already provisioned and active (see addresses[] on /email/domains). An address whose mailbox is still provisioning or failed re-incurs the fee until it is active.Not every domain provisions a mailbox per address — relay/send-only domains send from any from_address without a per-address mailbox, so this fee is 0 for them regardless. Trust this field on the quote: 0 means nothing extra is billed; a non-zero value is the one-time charge.Surfaced here before payment and folded into total_cost. If you send from a new address without a quote that included this fee, /email/send returns 402 mailbox_provisioning_required (re-quote with the exact from_address).

number

Total cost (registration + service + mailbox provisioning fees)

string

Quote ID to use in the send request

string

Domain status: verified, provisioning, unprovisioned, or blocked

string

Echoed only when the server picked the address (caller omitted it). Use it on /email/send or omit from_address on send — the value is locked into the quote and replayed automatically.

boolean

true when the server picked from the agent’s active pool.

string

Non-blocking advisory. Surface it to the user and consider deferring:

pinned_domain_warming — a pinned from_address whose domain is still warming (warmup score below threshold). Pinning bypasses the warmup gate.
pinned_over_limit — a pinned domain already at/over its daily_send_limit for today.

The same field appears on the /email/send response. Pinned sends are never blocked by warmup/limit — branch on warning to defer.

string

no_sending_domain (HTTP 400) when you pass no from_address and own no rotation-eligible domain. There is no shared fallback sender — provision a domain (pass a from_domain to register) or pin one you own. reason is empty (no domains) or exhausted (all warming/over-cap).

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: <your_x402_signature>" \
  -d '{
    "from_address": "[email protected]",
    "to_address": "[email protected]",
    "subject": "Hello",
    "body": "Test email"
  }'

const response = await fetch(
  "https://win.oneshotagent.com/v1/tools/email/quote",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-Payment-Proof": paymentProof,
    },
    body: JSON.stringify({
      from_address: "[email protected]",
      to_address: "[email protected]",
      subject: "Hello",
      body: "Test email",
    }),
  },
);

{
  "domain": "yourdomain.com",
  "is_new": true,
  "available": true,
  "registration_fee": 10.0,
  "service_fee": 0.01,
  "mailbox_provisioning_fee": 0,
  "total_cost": 10.01,
  "currency": "USD",
  "quote_id": "quote_abc123",
  "status": "unprovisioned"
}

Bulk Usage

You can request a quote for sending independent emails to multiple recipients in a single request. Pass an array of strings to to_address.

The service_fee will scale based on the number of recipients. The registration_fee (if applicable) remains a one-time cost for the domain.

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "Content-Type: application/json" \
  -H "X-Payment-Proof: <your_x402_signature>" \
  -d '{
    "from_address": "[email protected]",
    "to_address": ["[email protected]", "[email protected]", "[email protected]"],
    "subject": "Hello Team",
    "body": "Weekly update..."
  }'

Domain Rotation

If the caller owns multiple domains (root or subdomains), /email/quote without from_address rotates across them instead of hardcoding one. The selector runs in a single FOR UPDATE SKIP LOCKED query so concurrent quote calls never double-book the same row past its daily cap. Eligibility gates (applied in SQL, AND-combined):

agent_id = caller
pool_status = 'active' (warming domains stay out of rotation until their reputation warmup score crosses WARMUP_ACTIVE_THRESHOLD)
daily_sent_count + recipientCount <= daily_send_limit (per-domain per-UTC-day cap; resets lazily on the first send after midnight)
warmup_score IS NULL OR warmup_score >= MIN_ROTATION_SCORE (default 60)

Ordering: last_used_at ASC NULLS FIRST (least-recently-used first). Side effects on success: last_used_at = NOW(), daily_sent_count += recipientCount. Committed at quote time so concurrent quotes can’t race past capacity. If you bail without calling /email/send, the reservation auto-releases (best-effort).

Picking a specific domain

Just pass from_address and the pool is skipped:

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "X-Agent-ID: <wallet>" -H "Content-Type: application/json" \
  -d '{
    "from_address": "[email protected]",
    "to_address": ["[email protected]"],
    "subject": "hi", "body": "..."
  }'

Letting the server rotate

curl -X POST https://win.oneshotagent.com/v1/tools/email/quote \
  -H "X-Agent-ID: <wallet>" -H "Content-Type: application/json" \
  -d '{
    "to_address": ["[email protected]"],
    "subject": "hi", "body": "..."
  }'
# →  { "from_address": "[email protected]", "rotation": true, "quote_id": "...", ... }
# (the rotated address is always a domain YOU own; if you own no eligible
#  domain the quote returns 400 no_sending_domain — there is no shared fallback)

The rotated address is always a domain you own; the mailbox local-part is ROTATION_DEFAULT_MAILBOX (env; default agent). For per-mailbox control, pass from_address explicitly. See GET /email/domains to inspect what’s in your pool, and the pause / resume endpoints to take a domain in or out of rotation without removing it.

Notes

Domain provisioning happens automatically during the send request
Quote is valid for 1 hour
For existing verified domains, registration_fee will be 0

OpenAPI Spec Send Email

Overview

Email

Email Inbox

Voice

SMS

Commerce

Enrichment

Verification

Research

Build

Notifications

Receipts & Analytics

Other

Compute

Browser

Get Email Quote

Authentication

Request Body

Response

Bulk Usage

Domain Rotation

Picking a specific domain

Letting the server rotate

Notes

​Authentication

​Request Body

​Response

​Bulk Usage

​Domain Rotation

​Picking a specific domain

​Letting the server rotate

​Notes

Authentication

Request Body

Response

Bulk Usage

Domain Rotation

Picking a specific domain

Letting the server rotate

Notes