Cold email infrastructure your code and agents can run.
SimpleInboxes gives technical teams one programmable layer for Microsoft 365, Google Workspace, AWS SMTP, domains, DNS, wallet controls, recovery, and inbox operations. Use REST when you want code, MCP when you want Codex or Claude to operate with you.
Run the same inbox ops from scripts, Codex, Claude, Slack, or your internal tools.
Preview, verify, retry, and export without exposing credentials in ad hoc chats.
Build the operating system around your inbox supply.
Cold email teams do not need another settings page. They need a way to provision, inspect, repair, and bill infrastructure from the same workflow their team already uses.
Order inbox infrastructure without opening tickets
Create workspaces, place orders, attach domains, manage inbox metadata, and track fulfillment from one programmable surface.
Treat DNS and nameservers like infrastructure
Search domains, update registrar nameservers, sync Cloudflare records, recheck propagation, and retry failed steps without dashboard hopping.
Bring damaged domains back into rotation
Submit domains into the Recovery Pool, check health lights, watch blacklist status, and reactivate domains when they are ready.
Let your agent manage infrastructure without guessing.
MCP turns SimpleInboxes into a tool your AI agents can call directly. That means Codex can inspect a stuck order, Claude can summarize client readiness, and your support workflow can move from chat to verified infrastructure state.
Treat inbox operations like infrastructure-as-code.
The goal is not to make developers click through a prettier dashboard. It is to make every operational action inspectable, repeatable, and safe to run from code, chat, or your own internal control plane.
Authenticate once
Use one SimpleInboxes API key for REST scripts, MCP agents, and internal tools.
Describe the desired state
Provider, workspaces, domains, inbox count, forwarding, DNS, warmup, and billing settings.
Let the platform execute
Provision inboxes, move nameservers, sync records, retry failures, and expose status as it changes.
React to lifecycle events
Wire order completion, credentials readiness, recovery status, and billing events into your ops stack.
The API covers the parts of cold email infrastructure that actually break.
Orders + inbox lifecycle
Create orders, track status, mutate inboxes, rotate passwords, update profile photos, and reupload credentials.
Domains + DNS
Search domains, attach owned domains, manage DNS, configure forwarding, sync Cloudflare, and recheck nameservers.
Workspaces + clients
Separate client infrastructure, billing modes, saved credentials, sending-tool defaults, and workspace summaries.
Recovery + deliverability ops
Run blacklist checks, monitor recovery status, reactivate healed domains, and keep domain decisions out of spreadsheets.
Wallet + billing
Read balances, transfer funds, configure auto-recharge, view invoices, and understand workspace-level spend.
Keys + guardrails
Create and revoke keys, validate credentials, keep app-only auth separate, and give agents scoped operational access.
When you need the exact call, it is still here.
Use the sections below for authentication, MCP setup, base URL, error shape, and endpoint-level request details.
Authentication
All public API requests require an API key in the X-API-Key header. Bearer token authentication is only used by the signed-in web app, not by the public API.
curl https://app.simpleinboxes.com/api/v1/orders \
-H "X-API-Key: si_live_your_api_key"Create and manage API keys from your dashboard API Keys page after signing in. Key creation and revocation require a dashboard session, so those endpoints are not listed as public API-key-auth endpoints here.
MCP for Codex and Claude
SimpleInboxes exposes a remote HTTP MCP endpoint at /mcp. Connect it to Codex, Claude, or your own internal agent so your team can inspect account state, check DNS, preview orders, retry failed steps, export ready mailboxes, and adjust warmup without clicking through the dashboard.
Endpoint: https://app.simpleinboxes.com/mcp
Transport: streamable-http
Auth: Authorization: Bearer si_live_your_api_keyBase URL
https://app.simpleinboxes.com/api/v1Endpoint paths below are relative to this base URL. Requests and responses use JSON.
Errors
All errors return a consistent JSON shape with a machine-readable code and a human-readable message.
{
"success": false,
"error": {
"code": "NOT_FOUND",
"message": "Order not found"
}
}INVALID_REQUESTMissing or invalid parametersMISSING_API_KEY / INVALID_API_KEYInvalid or missing API keyNOT_FOUNDResource not foundRATE_LIMIT_EXCEEDEDToo many requestsSERVER_ERRORInternal server errorOrders
Create, list, update, cancel, and reactivate inbox orders. Includes inbox-mutation jobs (renames, password rotations, profile-photo updates) and bulk nameserver checks.
Inboxes
List inboxes, retrieve credentials, manage MFA, and rotate passwords or profile photos at the inbox level.
Domains
Search the registrar marketplace, manage owned domains, retrieve nameservers, run bulk DNS jobs, and reupload to sending tools.
DNS Records
Manage SPF / DKIM / DMARC / MX / custom records on every domain. All edits are auto-synced to Cloudflare.
Workspaces
Per-client workspaces for agency mode. Create, list, update, and configure sending-tool defaults at the workspace level.
Clients
Legacy clients API — name-keyed wrapper around workspaces. Manage clients, sending-tool credentials, and saved usernames.
Recovery Pool
Park burned, dormant, or unused domains so we restore their sender reputation. Submit blacklist removal requests, track health lights, and reactivate domains once they're ready.
Registrars
Auto-update nameservers at supported registrars (Porkbun, Spaceship, Name.com, Namecheap) via saved API credentials. No more clicking through registrar dashboards.
Wallet
Master + per-workspace wallets, transaction ledger, transfers, auto-recharge, and billing-mode toggles.
Billing
Invoices, billing history, custom invoices, and per-workspace billing details.
Payments
Stripe-backed top-ups, payment methods, and the Customer Portal.
API Keys
Programmatically manage your own API keys. (Key creation & revocation are also available in the dashboard.)