Mail Blaze MCP by usefulapi
REMOTE · MAILBLAZE.USEFULAPI.IO
Manage Mail Blaze lists, subscribers, templates, campaigns and reports; send transactional email.
Available components
Last scanned (4 hours ago)
Scores higher than 46% of remote servers
Reachable. Last reached 25 Oct 2026.
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 Usability81
- 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).Pass
- AI-judged instruction clarity (good).Pass
- Tool/resource definitions use about 2538 tokens (~97/item across 26 items; 26 tools + 0 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management0
- Stability not yet verified: not enough scan history yet (needs a 30-day window).Unverified
Tool Coverage82
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 47% of tool parameters carry a description.Partial
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.Pass
- An AI judge read all 27 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
Unverified: 1 category
A category scored 0 because we could not verify it: authentication we do not have, an unreachable endpoint, or not enough scan history. We only credit what we can confirm.
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.
- 25 Oct 26 61
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 25 Oct 2026 · Probed https://mailblaze.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 mailblaze.usefulapi.io. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| io. | present | 38690, 57355 | 8, 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://mailblaze.usefulapi.io/.well-known/oauth-protected-resource/mcp"
Bearer realm="OAuth", resource_metadata="https://mailblaze.usefulapi.io/.well-known/oauth-protected-resource/mcp"Protected resource metadata
| Document | https://mailblaze.usefulapi.io/.well-known/oauth-protected-resource/mcp |
|---|---|
| Retrieved | Yes |
| Resource | https://mailblaze.usefulapi.io/mcp |
| Authorisation server | https://mailblaze.usefulapi.io |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://mailblaze.usefulapi.io/mcp | Redirected | 302 | https://usefulapi.io/mailblaze/ |
| http (plaintext) | http://mailblaze.usefulapi.io/mcp | Inconclusive | 302 | http://mailblaze.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 →
mailblaze_add_subscriber Add a subscriber ~156
WRITE, MAY SEND A CONFIRMATION EMAIL: add one subscriber to a mailing list. Depending on the list's settings Mail Blaze may send the person a confirmation (double opt-in) email. Only add people who agreed to receive your email. An email that is already on the list answers with a conflict error.
| Name | Type | Req | Description |
|---|---|---|---|
| custom_fields | object | – | Custom field values keyed by the field's tag (see mailblaze_list_list_fields), e.g. {"PHONE": "+1 555 0100"}. |
| string | yes | – | |
| first_name | string | – | Sets the FNAME field. |
| last_name | string | – | Sets the LNAME field. |
| list_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_add_subscribers_bulk Add or update subscribers in bulk ~91
WRITE, MAY SEND CONFIRMATION EMAILS: add up to 100 subscribers to a mailing list in one request; an email already on the list is updated instead. Depending on the list's settings Mail Blaze may send confirmation emails. Only add people who agreed to receive your email.
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| subscribers | array | yes | 1 to 100 subscribers. |
No output schema declared.
No examples provided.
mailblaze_create_campaign Create and schedule a campaign ~226
WRITE, SENDS EMAIL TO PEOPLE: create a campaign for a mailing list (or one of its segments) from an existing template and schedule it for send_at. Once it goes out it reaches every subscriber of the list or segment, may use sending credit and cannot be recalled. Confirm the list, segment, subject, template and send time with the user before calling. Needs a template uid (mailblaze_list_templates) and a list uid (mailblaze_list_lists).
| Name | Type | Req | Description |
|---|---|---|---|
| from_email | string | yes | Sender address; it must be a verified sender in Mail Blaze. |
| from_name | string | yes | – |
| list_uid | string | yes | – |
| name | string | yes | Internal campaign name. |
| reply_to | string | yes | – |
| segment_uid | string | – | Send only to this segment of the list. |
| send_at | string | yes | When to send, 'YYYY-MM-DD HH:MM:SS' (interpreted by Mail Blaze in the account's time zone). |
| subject | string | yes | – |
| template_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_create_template Create an email template ~68
WRITE: create an email template from HTML (the tool base64-encodes it). Mail Blaze requires the HTML to contain an unsubscribe link. Sends nothing.
| Name | Type | Req | Description |
|---|---|---|---|
| html | string | yes | The full HTML of the email, including an unsubscribe link. |
| name | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_find_subscriber_by_email Find a subscriber by email ~54
Look up a subscriber in one list by email address. Returns the subscriber (with its uid) or a not-found error.
| Name | Type | Req | Description |
|---|---|---|---|
| string | yes | – | |
| list_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_get_campaign Get a campaign ~37
Get one campaign by uid: sender, subject, list, template, status and schedule.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_get_campaign_inbox_breakdown Get a campaign's inbox breakdown ~42
Inbox-provider breakdown (e.g. Gmail, Outlook, Yahoo) of a campaign's delivery.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_get_campaign_summaries Get campaign report summaries ~75
Bulk report summary (sent, opens, clicks, bounces, unsubscribes) for up to 50 campaigns in one call. Read-only (it is a POST in the API only because of the id list).
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_uids | array | yes | 1 to 50 campaign uids. |
No output schema declared.
No examples provided.
mailblaze_get_list Get a mailing list ~46
Get one mailing list by its uid: general settings, default sender, company details and counts.
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | List uid from mailblaze_list_lists. |
No output schema declared.
No examples provided.
mailblaze_get_report_job Get a report job's status ~45
Status (and result when finished) of an asynchronous report job, as returned in a 202 reply with a job_id.
| Name | Type | Req | Description |
|---|---|---|---|
| job_id | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_get_subscriber Get a subscriber ~62
Get one subscriber of a list by subscriber uid (status, fields, dates).
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| subscriber_uid | string | yes | Subscriber uid from mailblaze_list_subscribers or mailblaze_find_subscriber_by_email. |
No output schema declared.
No examples provided.
mailblaze_get_subscriber_activity Get a subscriber's activity ~104
Email activity (sends, opens, clicks, bounces) of one subscriber by email address, optionally limited to one list. Cursor-paged.
| Name | Type | Req | Description |
|---|---|---|---|
| cursor | string | – | The next_cursor from the previous reply, passed back exactly as returned. Omit for the first page. |
| string | yes | – | |
| limit | integer | – | Events per page (default 100, max 1000). |
| list_uid | string | – | – |
No output schema declared.
No examples provided.
mailblaze_get_template Get an email template ~30
Get one email template by uid (name and content).
| Name | Type | Req | Description |
|---|---|---|---|
| template_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_get_transactional_email Get a transactional email ~36
Get one transactional email by uid: recipient, subject, status and timestamps.
| Name | Type | Req | Description |
|---|---|---|---|
| email_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_list_campaign_events List a campaign's opens, clicks, bounces or unsubscribes ~134
List the individual events of a campaign by kind: opens, clicks, bounces or unsubscribes. Cursor-paged: pass the reply's next_cursor back until it is null. For very large campaigns Mail Blaze answers 202 with a job_id; check it with mailblaze_get_report_job.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_uid | string | yes | – |
| cursor | string | – | The next_cursor from the previous reply, passed back exactly as returned. Omit for the first page. |
| kind | string | yes | – |
| limit | integer | – | Events per page (default 100, max 1000). |
No output schema declared.
No examples provided.
mailblaze_list_campaigns List campaigns ~67
List the account's email campaigns (uid, name, status, dates). Use the campaign uid for details and reports.
| Name | Type | Req | Description |
|---|---|---|---|
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_list_list_fields List a list's custom fields ~91
List the fields of a mailing list (label, tag, type, required). The tags (EMAIL, FNAME, LNAME, custom ones) are the keys used when adding or updating subscribers.
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_list_lists List mailing lists ~92
List the account's mailing lists (name, uid, subscriber counts, defaults). Use the list uid in the other tools. Paged: page + per_page.
| Name | Type | Req | Description |
|---|---|---|---|
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
| per_page | integer | – | Lists per page (default set by Mail Blaze). |
No output schema declared.
No examples provided.
mailblaze_list_segments List a list's segments ~74
List the segments defined on a mailing list (uid, name). A segment uid can be used when creating a campaign.
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_list_subscribers List subscribers ~80
List the subscribers of a mailing list (sets of 10 per page; use page to go on). Contains personal data (emails, names).
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_list_templates List email templates ~63
List the account's email templates (uid, name). A template uid is needed to create a campaign.
| Name | Type | Req | Description |
|---|---|---|---|
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_list_transactional_emails List transactional emails ~65
List the transactional emails sent through the account (uid, recipient, subject, status). Paged.
| Name | Type | Req | Description |
|---|---|---|---|
| page | integer | – | Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty). |
No output schema declared.
No examples provided.
mailblaze_resubscribe_subscriber Resubscribe a subscriber ~62
WRITE: set a previously unsubscribed subscriber back to subscribed so campaigns reach them again. Only do this when the person asked to be re-added (consent).
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| subscriber_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_send_transactional_email Send a transactional email ~249
WRITE, SENDS ONE EMAIL NOW: send a single one-to-one email to one recipient through Mail Blaze. It leaves immediately, uses sending credit and cannot be recalled. Give either html (the body) or template_id (a transactional template, with merge_tags covering every tag in it), not both. Confirm the recipient and content with the user before calling. Not for bulk or marketing mail; use a campaign for that.
| Name | Type | Req | Description |
|---|---|---|---|
| from_email | string | yes | Sender address; it must be a verified sender in Mail Blaze. |
| from_name | string | yes | Sender name (required by Mail Blaze). |
| html | string | – | HTML body (the tool base64-encodes it). Omit when using template_id. |
| merge_tags | object | – | Template merge tags (required with template_id); every tag in the template must be present. |
| reply_to_email | string | – | – |
| reply_to_name | string | – | – |
| subject | string | yes | – |
| template_id | string | – | Transactional template id. Omit when sending html. |
| to_email | string | yes | – |
| to_name | string | yes | Recipient name (required by Mail Blaze). |
No output schema declared.
No examples provided.
mailblaze_unsubscribe_subscriber Unsubscribe a subscriber ~89
WRITE: set a subscriber's status to unsubscribed so they receive no more campaigns from this list. By default Mail Blaze also adds the address to the account's local blacklist. Do this only when the person asked to stop (or a data-protection request requires it). The subscriber record is kept.
| Name | Type | Req | Description |
|---|---|---|---|
| list_uid | string | yes | – |
| subscriber_uid | string | yes | – |
No output schema declared.
No examples provided.
mailblaze_update_subscriber Update a subscriber ~138
WRITE: update a subscriber's name or custom fields. Pass the subscriber's current email (Mail Blaze requires it) plus only the values to change. Does not change subscription status.
| Name | Type | Req | Description |
|---|---|---|---|
| custom_fields | object | – | Custom field values keyed by the field's tag (see mailblaze_list_list_fields), e.g. {"PHONE": "+1 555 0100"}. |
| string | yes | The subscriber's email (Mail Blaze requires it on update). | |
| first_name | string | – | – |
| last_name | string | – | – |
| list_uid | string | yes | – |
| subscriber_uid | string | yes | – |
No output schema declared.
No examples provided.
How do I install the Mail Blaze MCP by usefulapi server?
Mail Blaze MCP by usefulapi is a hosted endpoint at https://mailblaze.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 · mailblaze.usefulapi.io
claude mcp add --transport http io-usefulapi-mailblaze 'https://mailblaze.usefulapi.io/mcp'
What is the Mail Blaze MCP by usefulapi server?
Mail Blaze MCP by usefulapi is listed in the public MCP registry as io.usefulapi/mailblaze. Manage Mail Blaze lists, subscribers, templates, campaigns and reports; send transactional email. This page covers its hosted endpoint (https://mailblaze.usefulapi.io/mcp).
Is the Mail Blaze MCP by usefulapi server safe to use?
Mail Blaze MCP by usefulapi scores 61 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 Mail Blaze MCP by usefulapi server expose?
Mail Blaze MCP by usefulapi exposes 26 tools: mailblaze_list_lists, mailblaze_get_list, mailblaze_list_list_fields, mailblaze_list_segments, mailblaze_list_subscribers, and 21 more. Their descriptions and schemas cost roughly 2,276 tokens of context every time the server is loaded.
Does the Mail Blaze MCP by usefulapi server require authentication?
Yes. Mail Blaze 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 Mail Blaze MCP by usefulapi server still maintained?
Mail Blaze MCP by usefulapi is still listed as active in the MCP registry. We last reached this channel on 25 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.