MCP HeartbeatTHE MCP OBSERVATORY
Public workspace

Explore

Evidence for your next connection.

Independent measurements of remote MCP servers. Every observation has a timestamp.

Read-only probes

MCP server · Payments & trading

Email Preflight

By tasuyoapp-ctrl

x402 v2 payment requests; relays compatible clients' signed payments to the existing product API.

Source codeFinance & paymentsProductivity & docs
Connect to Email Preflight
Checks passed
10 / 22

4 failed · 8 not measured

Median response
1146 ms

Median of successful probes over 7 days

30-day uptime
Not measured

Share of countable probes over 30 days, including daily rollups. Auth challenges are excluded.

Discovered tools
3

Tool definitions returned by this server

Independent monitoring

Health & checks

Status history

Responded

The server completed its last measured handshake. This is an observation, not a guarantee.

Last checked
Check summary by test group
Test areaPassedFailedUnmeasured
ConnectionCan a client connect and discover tools?
500
Reliability & speedDoes it respond consistently and quickly?
004
Access & authenticationWhat is required to use this server?
102
Tool qualityAre the tool definitions usable by an agent?
220
Publisher identityCan the publisher be traced to its source?
222

Unmeasured means there is not enough evidence to decide. How these checks work

Inspect individual checks 22 recorded

Core

  • Pass
    Reachable

    Latest probe returned HTTP 200 in 1146 ms.

  • Pass
    Valid handshake

    protocolVersion 2025-11-25, serverInfo.name email-preflight-mcp.

  • Pass
    Lists tools

    tools/list returned 3 tools.

  • Pass
    Current protocol

    Negotiated 2025-11-25. The bar is 2025-06-18 or newer.

  • Pass
    HTTPS

    The endpoint URL is https.

Performance

  • Not measured
    Fast (p50)

    Median latency 1146 ms over 1 samples in 7 days. The bar is 1000 ms. Need at least 5 samples.

  • Not measured
    Consistent (p95)

    95th percentile 1146 ms over 1 samples in 7 days. The bar is 3000 ms. Need at least 20 samples.

  • Not measured
    Reliable (uptime)

    1 of 1 attempts returned a tool list in 30 days (100%). The bar is 99%. Need at least 30 samples.

  • Not measured
    Stable tool list

    Fewer than two successful probes in 30 days, so tool-list stability is not measured.

Access

  • Pass
    Open access

    tools/list succeeded with no credential, and the record declares none.

  • Not measured
    Standard auth

    Auth is not required, so the OAuth metadata check does not apply.

  • Not measured
    Free tier cited

    No publisher quote has been checked.

Tools

  • Pass
    Tools described

    Every tool description is at least 20 characters.

  • Pass
    Valid input schemas

    Every inputSchema is a JSON Schema object.

  • Fail
    Parameters documented

    1 of 3 parameters have a description (33%). The bar is 80%.

  • Fail
    Safety hints

    3 tools set neither readOnlyHint nor destructiveHint.

Publisher

  • Pass
    Verified namespace

    Listed in the Official MCP Registry.

  • Not measured
    Website matches publisher

    This namespace is not a reverse domain, so the website comparison does not apply.

  • Fail
    Source repo linked

    No repository URL is on file.

  • Fail
    Repo owner matches

    The GitHub repository owner does not match the namespace login.

  • Pass
    Recently updated

    Updated 2026-10-16T03:40:24.368594Z, within 180 days.

  • Not measured
    Open-source licence

    No GitHub repository to ask about a licence.

Start using Email Preflight

Connect to this server

Choose your client, copy the configuration, then enable the server in your client’s MCP settings.

Run this command in your terminal, then restart Claude Code.

Claude Code

claude mcp add --transport http email-preflight https://email-preflight-mcp.onrender.com/mcp

Capabilities

Tools 3

email_check_mini

Check email syntax, MX and local domain classes with the existing API. $0.001 USDC on Base mainnet. MX does not prove mailbox existence. Unpaid calls return x402 v2 requirements for this request. A compatible client may repeat identical arguments with its own PaymentPayload in params._meta["x402/payment"]. The adapter does not sign or settle independently.

Discovered
email_preflight

Use before sending or processing an email when you need current preflight facts about the address. For $0.001 USDC on Base mainnet, the existing Email Preflight API checks six facts: syntax validity, domain availability, MX availability, disposable-email detection, role-account detection, and free-provider detection. Example paid result shape: { email: "user@example.com", syntax: "valid", domain: "exists", mx: "found", disposable: "not_listed", role_based: "not_detected", free_provider: "not_detected" }. MX records do not prove that a mailbox exists. Unpaid requests return the original upstream HTTP 402 challenge. A compatible x402 client may retry with its own signed PaymentPayload in params._meta["x402/payment"]. This adapter never signs, owns a wallet, or settles independently.

Discovered
url_preflight

Inspect public HTTP/HTTPS URL response metadata through the existing safe URL API. $0.001 USDC on Base mainnet. Unpaid calls return x402 v2 requirements. A compatible client may repeat the identical url argument with its own signed PaymentPayload in params._meta["x402/payment"]. This bridge does not fetch that URL directly, sign payments, or settle independently.

Discovered

Recent measurements

Probe history

View status
Latest stored probes. Raw probe rows are kept for 14 days.
CheckedResultResponseTools
Connected1146 ms3

Related servers

All alternatives

Same function and industry, ranked by checks passed then median latency.

Explore alternatives to Email Preflight