Public MX receiving
Receive mail from any external provider through a production-shaped SMTP edge.
Feature reference
Everything needed to finish the email step.
Receive, match, extract, inspect, simulate, and operate without stitching together a mailbox, a polling loop, a parser, and a billing guess.
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Receive
Real email enters through real protocols.
Exercise the same routing and transport behavior that production depends on.
Capture SMTP
Authenticate from staging, accept any recipient, and guarantee that nothing is delivered externally.
Deterministic inboxes
Map run IDs to stable addresses for parallel CI without passing mailbox state between workers.
Shared domains
Start immediately with an InboxSpec-owned domain for smoke tests and evaluation.
Custom domains
Use a receiving domain your own product accepts through REST, SDK or CLI.
Attachments
Preserve exact bytes and return short-lived download URLs when the caller asks for them.
Find and extract
Ask for the artifact, not the inbox.
Matching and extraction collapse multiple network calls and local parsing into one typed result.
Blocking wait
Hold one server-side call until the right message arrives. Waiting is free and exempt from rate limits.
Structured match rules
Match subject, sender, recipients, body text, headers, presence of codes, and classified link types.
Code extraction
Normalize and confidence-rank verification codes across text and HTML content.
Link classification
Return verify, sign-in, reset-password, unsubscribe, and other links as distinct kinds.
Token-bounded bodies
Return compact body projections by default, with an explicit pointer to full content.
Timeout diagnostics
A timed-out result reports non-matching arrivals and a repair hint instead of throwing an ambiguous error.
Integrate
One behavior across every interface.
Pick the transport that fits the worker. Do not trade away semantics to get it.
First-class MCP
Every tool executes against the core domain model, with descriptions written for autonomous callers.
REST API
OpenAPI 3.1 generated from the schemas that validate live requests, including typed error variants.
TypeScript SDK
A typed client for inbox, message, domain, webhook, retention, audit, and usage workflows.
Command-line interface
Stable exit codes separate no match, bad input, authentication, quota, and service failure.
Signed webhooks
Locally verifiable HMAC signatures, retries, and an inspectable delivery log.
Live browser stream
Short-lived inbox-scoped tokens push arrivals directly to the console through Server-Sent Events.
Simulate
Make failure reproducible.
Fixed addresses produce known SMTP outcomes without configuring a special inbox first.
Hard bounce
Exercise a permanent 550 rejection and verify the application stops retrying.
Soft bounce
Return a temporary mailbox-full response and verify retry behavior.
Greylisting
Reject the first attempt temporarily, then accept a later delivery.
Delayed delivery
Hold acceptance for a documented interval so timeout logic can be measured.
Oversized message
Return the correct SMTP size failure before the application treats the send as complete.
Complaint path
Exercise downstream complaint handling with a stable, documented simulator address.
Operate
Understand the run while it is running.
Operational surfaces explain current state without becoming another source of hidden state.
Usage ledger
Postgres remains the billing system of record, with every accepted message represented once.
Audit trail
Read project audit events through REST or the SDK. The console does not list audit events.
Visible plan limits
See message quota, request rate, concurrent waits, and retention before a run depends on them.
Retention controls
Messages expire after their retention period. Set inbox retention and clean up test messages through the API.
Deliverability signals
Attach authentication verdicts, spam score, and scanning state to the message they describe.
Typed health boundary
The service status page reports recent email-delivery checks. Missing or stale checks are shown as unknown.
Protect
Credentials stay narrow and disposable.
Human identity, project access, and message access remain separate principals.
Hashed secrets
API keys and capture credentials are stored as SHA-256 hashes and displayed only once.
Per-key scopes
Give CI only the routes it needs, and revoke the exact credential that stopped being trustworthy.
Project isolation
Ownership checks sit at every parameterized boundary, with not found and not yours deliberately identical.
SSRF protection
Reject unsafe webhook destinations at registration, before a delivery attempt can touch the network.
Sanitized HTML
Read sanitized HTML through the API. The console shows delivery details and codes; it does not preview email HTML.
Bounded ingest
Per-project ceilings cap the damage from leaked relay credentials or abusive receiving domains.