Accept
MX or authenticated capture SMTP receives the message.
The complete product
From SMTP delivery to useful artifact.
One platform receives the message, verifies it, wakes the caller, extracts what matters, and explains every failure along the way.
Connect to hosted InboxSpec with REST examples for JavaScript, Python, Java and more. SDK and CLI require access to our private release. Connect your agent with hosted MCP and a project key. Choose a connection method.
Five stages. One accountable path.
The acceptance path is intentionally bounded. Slow advisory checks become explicit temporary results instead of holding SMTP open indefinitely.
Verify
Authentication checks run within capped budgets. Spam and malware scoring may be disabled; unscored mail is not a clean verdict.
Extract
Codes and links are normalized, ranked, and classified by purpose.
Wake
A blocked wait or live inbox stream receives the arrival instantly.
Account
The audit trail and message meter record the same accepted event.
Agent runtime
A tool call shaped like the job.
An agent asks for the verification message, not a page of message summaries it must repeatedly inspect.
Explore agent runtime and MCPIllustrative MCP request and abbreviated result for a registered inbox. Use the setup guide to connect; handle status: "timeout" before reading message.
wait_for_message({
inbox: "signup.ci-4182@inbox.acme.test",
match: { has_code: true, has_link_kind: "verify" },
timeout_ms: 60000
})
→ {
status: "matched",
message: { id: "msg_example", codes: ["384921"],
links: [{ kind: "verify", href: "https://example.test/verify" }] },
waited_ms: 641
}First-class tools
Tool descriptions name relationships, failure variants, and matching rules so the model does not invent them.
Bounded responses
Body projections are capped and point to full content. A marketing email cannot consume the agent’s context window by surprise.
Side-effect-free reads
A human viewing a message never changes what a concurrent agent sees. Consumption is explicit, not a hidden read flag.
Receiving
Real mail, realistic constraints.
Test the path your customers actually use, including DNS, authentication, routing, and attachments.
Instant inboxes
Any valid tag creates an inbox on first receipt. Deterministic run IDs keep parallel jobs isolated.
Custom domains
Manage custom receiving domains through REST, SDK or CLI, with required and advisory DNS records clearly separated.
Authentication verdicts
SPF, DKIM, and DMARC results stay attached to the message that produced them.
Live delivery
Server-Sent Events push arrivals to the browser while blocking waits wake API and MCP callers.
Capture SMTP
Let staging send. Let nothing escape.
Point the application at a real authenticated transport that accepts any destination, files the message, and never delivers it externally.
Real SMTP behavior
Use STARTTLS and AUTH on standard submission ports. Exercise the transport code your application already ships.
Original recipient retained
Every captured message keeps the third-party address your application attempted to contact.
Project credentials
Mint and delete scoped relay credentials independently from API keys. Secrets are shown once.
Bounded acceptance
Per-project ceilings stop a leaked credential from turning into unbounded storage cost.
Project dashboard
See your test results. Manage your projects.
Create projects, manage API keys, and watch codes and delivery details in the browser. Read full emails through the API.
Project boundaries
Each project keeps its own mail and API keys. Your account shows the projects you have access to.
Live inbox view
See senders, subjects and verification codes as messages arrive. Copy a code for your test.
Credential lifecycle
Mint project API keys with default permissions, revoke them visibly, and see last-used state without exposing secrets again.
Usage and limits
Check shared workspace usage in Plan and billing, and each project’s limits on its Project limits page.
Operations
Failure modes designed into the contract.
The system makes the repair path visible. Timeouts return a result, quota and throttling return typed errors, and transient diagnostics cannot stall acceptance.
Timed out200 · timeout
Inbox missing404 · inbox_not_found
Quota spent402 · quota_exceeded
Rate limited429 · rate_limited
Service fault5xx · retryable