curl --request POST \
  --url https://brew.new/api/v1/emails \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "Create a welcome email for new customers who joined Brew today."
}
'

{
  "response": "No email was generated."
}

{
  "emailId": "eml_2SmZOWV3ZQ7W5x6g3m4p",
  "emailVersionId": "emv_2SmZOWV3ZQ7W5x6g3m4p_v1",
  "html": "<!DOCTYPE html><html><body>Welcome to Brew.</body></html>",
  "previewImage": "https://storage.example.com/emails/eml_2SmZOWV3ZQ7W5x6g3m4p.png",
  "group": null
}

{
  "error": {
    "code": "INVALID_REQUEST",
    "type": "invalid_request",
    "message": "Request validation failed.",
    "suggestion": "Fix the field reported in `param` and retry.",
    "docs": "https://docs.brew.new/api-reference/api/errors",
    "param": "prompt"
  }
}

{
  "error": {
    "code": "INVALID_API_KEY",
    "type": "authentication_error",
    "message": "The provided API key is invalid.",
    "suggestion": "Check the API key format and retry with a valid active key.",
    "docs": "https://docs.brew.new/api-reference/api/authentication"
  }
}

{
  "error": {
    "code": "INSUFFICIENT_CREDITS",
    "type": "payment_required",
    "message": "This operation required more credits than the 0 remaining on the 'free' plan. See the per-operation cost in GET /v1/help.",
    "suggestion": "Upgrade your plan or wait for the next billing period to reset. Check your balance up front with GET /v1/usage.",
    "docs": "https://docs.brew.new/api-reference/api/credits",
    "details": {
      "cost": 2,
      "remaining": 0,
      "planKey": "free"
    }
  }
}

{
  "error": {
    "code": "INSUFFICIENT_PERMISSIONS",
    "type": "authorization_error",
    "message": "The caller does not have the required permission.",
    "suggestion": "Use an API key or session with the required permission.",
    "docs": "https://docs.brew.new/api-reference/api/authentication",
    "param": "emails"
  }
}

{
  "error": {
    "code": "BRAND_NOT_FOUND",
    "type": "not_found",
    "message": "The requested brand was not found.",
    "suggestion": "Verify in the dashboard that the brand bound to this API key still exists.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "IDEMPOTENCY_CONFLICT",
    "type": "conflict",
    "message": "The same idempotency key was reused with a different request payload.",
    "suggestion": "Reuse the original payload or send a new idempotency key.",
    "docs": "https://docs.brew.new/api-reference/api/idempotency"
  }
}

{
  "error": {
    "code": "BRAND_NOT_READY",
    "type": "invalid_request",
    "message": "The requested brand is not ready for email generation.",
    "suggestion": "Wait for brand extraction to complete (GET /v1/brand → ready) before generating emails.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "RATE_LIMITED",
    "type": "rate_limit",
    "message": "Too many requests.",
    "suggestion": "Wait for the retry window before sending another request.",
    "docs": "https://docs.brew.new/api-reference/api/rate-limits",
    "retryAfter": 42
  }
}

{
  "error": {
    "code": "INTERNAL_ERROR",
    "type": "internal_error",
    "message": "An unexpected error occurred.",
    "suggestion": "Retry the request. If it keeps failing, contact support.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "SERVICE_UNAVAILABLE",
    "type": "service_unavailable",
    "message": "Your credit balance could not be verified because a billing dependency is temporarily unavailable.",
    "suggestion": "Retry the request after a short delay.",
    "docs": "https://docs.brew.new/api-reference/api/credits",
    "retryAfter": 2
  }
}

Emails

Generate an email design

Generates a new design through the Brew email agent. Emails are pure DESIGNS in the decoupled model — no send state, no type. Sending happens later — POST /v1/sends delivers the design to a target (a saved audience, an inline list, or a single address) via a verified domain (or fires a one-off test with test: true), or a sendEmail node in an automation graph references the returned emailId + emailVersionId.

Returns 201 with { emailId, emailVersionId, html, previewImage?, group, subjectLine? } when a design was persisted, or 200 with { response } when the agent answered in prose without writing a design. Optional subjectLine sets the design-default inbox subject (POST /v1/sends still takes an explicit per-send subject). Optional targetGroupId (grp_… or ungrouped) or targetGroupName (resolve-or-create) — not both; omit to land Ungrouped. Unknown targetGroupId → 404 EMAIL_GROUP_NOT_FOUND. Supports Idempotency-Key for safe retries.

POST

emails

curl --request POST \
  --url https://brew.new/api/v1/emails \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "prompt": "Create a welcome email for new customers who joined Brew today."
}
'

{
  "response": "No email was generated."
}

{
  "emailId": "eml_2SmZOWV3ZQ7W5x6g3m4p",
  "emailVersionId": "emv_2SmZOWV3ZQ7W5x6g3m4p_v1",
  "html": "<!DOCTYPE html><html><body>Welcome to Brew.</body></html>",
  "previewImage": "https://storage.example.com/emails/eml_2SmZOWV3ZQ7W5x6g3m4p.png",
  "group": null
}

{
  "error": {
    "code": "INVALID_REQUEST",
    "type": "invalid_request",
    "message": "Request validation failed.",
    "suggestion": "Fix the field reported in `param` and retry.",
    "docs": "https://docs.brew.new/api-reference/api/errors",
    "param": "prompt"
  }
}

{
  "error": {
    "code": "INVALID_API_KEY",
    "type": "authentication_error",
    "message": "The provided API key is invalid.",
    "suggestion": "Check the API key format and retry with a valid active key.",
    "docs": "https://docs.brew.new/api-reference/api/authentication"
  }
}

{
  "error": {
    "code": "INSUFFICIENT_CREDITS",
    "type": "payment_required",
    "message": "This operation required more credits than the 0 remaining on the 'free' plan. See the per-operation cost in GET /v1/help.",
    "suggestion": "Upgrade your plan or wait for the next billing period to reset. Check your balance up front with GET /v1/usage.",
    "docs": "https://docs.brew.new/api-reference/api/credits",
    "details": {
      "cost": 2,
      "remaining": 0,
      "planKey": "free"
    }
  }
}

{
  "error": {
    "code": "INSUFFICIENT_PERMISSIONS",
    "type": "authorization_error",
    "message": "The caller does not have the required permission.",
    "suggestion": "Use an API key or session with the required permission.",
    "docs": "https://docs.brew.new/api-reference/api/authentication",
    "param": "emails"
  }
}

{
  "error": {
    "code": "BRAND_NOT_FOUND",
    "type": "not_found",
    "message": "The requested brand was not found.",
    "suggestion": "Verify in the dashboard that the brand bound to this API key still exists.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "IDEMPOTENCY_CONFLICT",
    "type": "conflict",
    "message": "The same idempotency key was reused with a different request payload.",
    "suggestion": "Reuse the original payload or send a new idempotency key.",
    "docs": "https://docs.brew.new/api-reference/api/idempotency"
  }
}

{
  "error": {
    "code": "BRAND_NOT_READY",
    "type": "invalid_request",
    "message": "The requested brand is not ready for email generation.",
    "suggestion": "Wait for brand extraction to complete (GET /v1/brand → ready) before generating emails.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "RATE_LIMITED",
    "type": "rate_limit",
    "message": "Too many requests.",
    "suggestion": "Wait for the retry window before sending another request.",
    "docs": "https://docs.brew.new/api-reference/api/rate-limits",
    "retryAfter": 42
  }
}

{
  "error": {
    "code": "INTERNAL_ERROR",
    "type": "internal_error",
    "message": "An unexpected error occurred.",
    "suggestion": "Retry the request. If it keeps failing, contact support.",
    "docs": "https://docs.brew.new/api-reference/api/errors"
  }
}

{
  "error": {
    "code": "SERVICE_UNAVAILABLE",
    "type": "service_unavailable",
    "message": "Your credit balance could not be verified because a billing dependency is temporarily unavailable.",
    "suggestion": "Retry the request after a short delay.",
    "docs": "https://docs.brew.new/api-reference/api/credits",
    "retryAfter": 2
  }
}

Authorizations

Authorization

string

header

default:Bearer brew_your_api_key

required

Send your Brew API key as Authorization: Bearer brew_xxx.

Headers

Idempotency-Key

string

Optional idempotency key for safe retries. Reusing the same key with the same request body returns the original response for 24 hours.

Required string length: 1 - 100

X-Brand-Id

string

The brand this request acts on. REQUIRED for organization-scoped credentials (otherwise 400 BRAND_ID_REQUIRED — there is no default brand); list ids with GET /v1/brands. Brand-scoped credentials may omit it, and sending a different brand returns 403 BRAND_SCOPE_MISMATCH. A brand outside your organization returns 404 BRAND_NOT_FOUND.

Required string length: 1 - 64

Body

application/json

Generation prompt plus optional source URLs / reference design. The brand comes from the credential (or the X-Brand-Id header on an organization-scoped one) and must not be passed in the body.

prompt

string

required

What the email is about — campaign goal, key content, offer, tone. The more specific (product names, dates, discount, audience), the better the design.

Minimum string length: 1

contentUrls

string<uri>[]

Up to 8 source URLs to build the email FROM — each is crawled and synthesized into one email (newsletters, recaps, product roundups).

Maximum array length: 8

referenceEmailId

string

An existing design (emailId from list_email_designs) to use as the style/layout reference for the new email.

Response

The agent answered in prose without writing a design ({ response }).

response

string

required

Minimum string length: 1

⌘I

Get started

Overview

Core concepts

Guides

MCP server

CLI

Public API v1

Generate an email design

Authorizations

Headers

Body

Response