Emailable MCP by usefulapi
REMOTE · EMAILABLE.USEFULAPI.IO
Verify email addresses with Emailable one by one or in batches, and read credits and batch results.
Available components
Last scanned (1 hour ago)
Scores higher than 46% of remote servers
Reachable. Last reached 17 Oct 2026.
Category CRM and Sales
How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. How we score → Why this is hard to score →
Endpoint Security78
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation is enforced on tool calls, advertised via RFC 9728 protected-resource metadata. Discovery is public, which costs nothing: no tool can be invoked without a token. View diagnostics → Pass
- HTTPS enforcement could not be verified: the plaintext port redirected somewhere other than https, so enforcement is unproven. View diagnostics → Unverified
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
- The authorisation server offers only Dynamic Client Registration (RFC 7591), which MCP 2026-07-28 deprecated in favour of Client ID Metadata Documents. View diagnostics → Partial
Transport & Reachability0
- Transport check failed: declared streamable-http, but the endpoint redirected instead of responding directly. See how to fix → View diagnostics → Fail
Schema Quality & AI Usability78
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (excellent).Pass
- Context-footprint check failed: tool/resource definitions use about 988 tokens (~247/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management17
- Stability observed for 5 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities60
- Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28. See how to fix → Fail
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 17 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 13 to 17. That category is still filling its 30-day observation window: 4 days of observed history at the previous scan, 5 at this one. The score rises as the window fills, whether or not the server changes.
- 14 Oct 26 +3
- The server rewrote its instructions, which are the text every model session reads security
- The server now declares the “prompts” capability functional
- First check of Schema quality: 100 functional
- New prompt “getting_started” functional
- Server version: 1.0.0 → 1.1.0 functional
- 13 Oct 26 0
- Stability: unverified → 0.03 ▲ functional
- 12 Oct 26 60
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 17 Oct 2026 · Probed https://emailable.usefulapi.io/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=usefulapi.io | CN=WE1,O=Google Trust Services,C=US | 13 Sept 2026 | 12 Dec 2026 | ECDSA 256 | ECDSA-SHA256 | d9be3287b0fde9630e825ba1f79bff3f |
| SANs: usefulapi.io, *.usefulapi.io | ||||||
| CN=WE1,O=Google Trust Services,C=US (CA) | CN=GTS Root R4,O=Google Trust Services LLC,C=US | 13 Dec 2023 | 20 Feb 2029 | ECDSA 256 | ECDSA-SHA384 | 7ff31977972c224a76155d13b6d685e3 |
| CN=GTS Root R4,O=Google Trust Services LLC,C=US (CA) | CN=GlobalSign Root CA,OU=Root CA,O=GlobalSign nv-sa,C=BE | 15 Nov 2023 | 28 Jan 2028 | ECDSA 384 | SHA256-RSA | 7fe530bf331343bedd821610493d8a1b |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of emailable.usefulapi.io. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| io. | present | 57355 | 8 | Verified |
| usefulapi.io. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication Enforced and verified
The endpoint asked for a token and published valid RFC 9728 metadata describing how to get one.
| Result | Enforced and verified |
|---|---|
| Enforced | On tool calls |
| HTTP status | 302 |
WWW-Authenticate challenge Bearer realm="OAuth", resource_metadata="https://emailable.usefulapi.io/.well-known/oauth-protected-resource/mcp"
Bearer realm="OAuth", resource_metadata="https://emailable.usefulapi.io/.well-known/oauth-protected-resource/mcp"Protected resource metadata
| Document | https://emailable.usefulapi.io/.well-known/oauth-protected-resource/mcp |
|---|---|
| Retrieved | Yes |
| Resource | https://emailable.usefulapi.io/mcp |
| Authorisation server | https://emailable.usefulapi.io |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://emailable.usefulapi.io/mcp | Redirected | 302 | https://usefulapi.io/emailable/ |
| http (plaintext) | http://emailable.usefulapi.io/mcp | Inconclusive | 302 | http://emailable.usefulapi.io/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
emailable_create_batch Create a batch verification ~235
SPENDS CREDITS: starts a bulk verification of up to 5000 email addresses. Emailable takes 1 credit per email when the batch is created, and if the account has too few credits it may charge the account's saved card to buy more. A test_ API key spends nothing. The batch cannot be cancelled here, and the call is never retried: if it fails or times out, check emailable_get_account before trying again, because a retry can charge twice. Returns the batch id; poll it with emailable_get_batch. Emailable's terms allow verification of opt-in subscribers' addresses. POST /v1/batch.
| Name | Type | Req | Description |
|---|---|---|---|
| confirm | boolean | yes | Must be true. It confirms the user agreed to spend 1 credit per email (and a possible card charge for missing credits). |
| emails | array | yes | The email addresses to verify, 1-5000. |
| response_fields | array | – | Only these fields in each result (default: all). |
| retries | boolean | – | Retry mail-server answers for accuracy (default true). false is faster but gives more unknown results. |
No output schema declared.
No examples provided.
emailable_get_account Get account and credits ~40
The Emailable account behind this API key: the owner's email and available_credits. Check it before a large batch. GET /v1/account.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
emailable_get_batch Get a batch verification ~258
Status and results of a batch made with emailable_create_batch: message, progress (processed/total), reason_counts and total_counts (deliverable, undeliverable, risky, unknown). Batches of up to 1,000 emails also return the results inline in `emails` (30 days). They come in pages: up to `limit` results, fewer if the reply would get too long; ask for the next page with emails_page.next_offset. A bigger batch returns download_file, a temporary link (5 days) to a ZIP of a CSV: share it only with the account owner. Free to call. GET /v1/batch.
| Name | Type | Req | Description |
|---|---|---|---|
| id | string | yes | The batch id. |
| include_emails | boolean | – | Include per-email results (default true). false returns the counts only. |
| limit | integer | – | Most results per call, 1-1000 (default 100). A reply can hold fewer; use emails_page.next_offset for the next page. |
| offset | integer | – | First result to return (default 0). |
| partial | boolean | – | Include the results so far while the batch is still running (only for batches of up to 1,000 emails). |
No output schema declared.
No examples provided.
emailable_verify_email Verify one email address ~247
SPENDS CREDITS: verifies one email address and uses 1 Emailable credit (a test_ API key spends none). Returns state (deliverable, undeliverable, risky, unknown), reason, score (0-100), and flags: disposable, free, role, accept_all, no_reply, mailbox_full, plus did_you_mean (a typo fix), the detected user/domain/tag, mx_record and smtp_provider. A credit is returned for an unknown result. The call is never retried automatically. If the reply is {status: "try_again"}, the check took longer than the timeout: call again with the same email; repeats within 5 minutes are not charged. Emailable's terms allow verification of opt-in subscribers' addresses. GET /v1/verify.
| Name | Type | Req | Description |
|---|---|---|---|
| accept_all | boolean | – | Run the accept-all check (default false). It slows the reply. |
| string | yes | The email address to verify. | |
| smtp | boolean | – | Run the SMTP step (default true). false is faster but much less accurate. |
| timeout | integer | – | Seconds to wait for the result, 2-10 (default 5). |
No output schema declared.
No examples provided.
How do I install the Emailable MCP by usefulapi server?
Emailable MCP by usefulapi is a hosted endpoint at https://emailable.usefulapi.io/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · emailable.usefulapi.io
claude mcp add --transport http io-usefulapi-emailable 'https://emailable.usefulapi.io/mcp'
What is the Emailable MCP by usefulapi server?
Emailable MCP by usefulapi is listed in the public MCP registry as io.usefulapi/emailable. Verify email addresses with Emailable one by one or in batches, and read credits and batch results. This page covers its hosted endpoint (https://emailable.usefulapi.io/mcp).
Is the Emailable MCP by usefulapi server safe to use?
Emailable MCP by usefulapi scores 64 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the Emailable MCP by usefulapi server expose?
Emailable MCP by usefulapi exposes 4 tools: emailable_get_account, emailable_verify_email, emailable_create_batch, emailable_get_batch. Their descriptions and schemas cost roughly 780 tokens of context every time the server is loaded.
Does the Emailable MCP by usefulapi server require authentication?
Yes. Emailable MCP by usefulapi asked us for credentials when we connected, so you will need to authorise it in your MCP client before it can do anything.
Is the Emailable MCP by usefulapi server still maintained?
Emailable MCP by usefulapi is still listed as active in the MCP registry. We last reached this channel on 17 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.