# Mail Blaze MCP by usefulapi (remote · mailblaze.usefulapi.io)

Manage Mail Blaze lists, subscribers, templates, campaigns and reports; send transactional email.

- Trust score: 61/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-25

## Components

- remote · `mailblaze.usefulapi.io`: 61/100 (this document), [markdown](https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze.md), [page](https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze)

## Channel facts

- Endpoint: `https://mailblaze.usefulapi.io/mcp`
- Transports: `streamable-http`
- Auth: `required`
- Version: `1.0.3`

## Trust breakdown

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. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-10-25.

- **Endpoint Security**: 78/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - 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.
  - HTTPS enforcement could not be verified: the plaintext port redirected somewhere other than https, so enforcement is unproven.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
  - The authorisation server offers only Dynamic Client Registration (RFC 7591), which MCP 2026-07-28 deprecated in favour of Client ID Metadata Documents.
- **Transport & Reachability**: 0/100
  - Transport check failed: declared streamable-http, but the endpoint redirected instead of responding directly.
- **Schema Quality & AI Usability**: 81/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (good).
  - Tool/resource definitions use about 2538 tokens (~97/item across 26 items; 26 tools + 0 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 0/100
  - Stability not yet verified: not enough scan history yet (needs a 30-day window).
- **Tool Coverage**: 82/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 47% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - All 1 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 27 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 60/100
  - Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28.

**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.

## Install

### 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.

### Claude

```bash
claude mcp add --transport http io-usefulapi-mailblaze 'https://mailblaze.usefulapi.io/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "io-usefulapi-mailblaze": {
      "url": "https://mailblaze.usefulapi.io/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "io-usefulapi-mailblaze": {
      "type": "http",
      "url": "https://mailblaze.usefulapi.io/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.io-usefulapi-mailblaze]
url = "https://mailblaze.usefulapi.io/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "io-usefulapi-mailblaze": {
      "type": "remote",
      "url": "https://mailblaze.usefulapi.io/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add io-usefulapi-mailblaze --url 'https://mailblaze.usefulapi.io/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  io-usefulapi-mailblaze:
    url: "https://mailblaze.usefulapi.io/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "io-usefulapi-mailblaze": {
      "Transport": "http",
      "Url": "https://mailblaze.usefulapi.io/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add io-usefulapi-mailblaze -t streamable-http -u 'https://mailblaze.usefulapi.io/mcp'
```

### Other

```json
{
  "mcpServers": {
    "io-usefulapi-mailblaze": {
      "type": "http",
      "url": "https://mailblaze.usefulapi.io/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-10-25 (score 61)

First indexed and scored.

## MCP tools (26)

### `mailblaze_list_lists` (~92 tokens)

List mailing lists

List the account's mailing lists (name, uid, subscriber counts, defaults). Use the list uid in the other tools. Paged: page + per_page.

Input parameters:

- `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).

### `mailblaze_get_list` (~46 tokens)

Get a mailing list

Get one mailing list by its uid: general settings, default sender, company details and counts.

Input parameters:

- `list_uid` (string, required): List uid from mailblaze_list_lists.

### `mailblaze_list_list_fields` (~91 tokens)

List a list's custom fields

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.

Input parameters:

- `list_uid` (string, required)
- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_list_segments` (~74 tokens)

List a list's segments

List the segments defined on a mailing list (uid, name). A segment uid can be used when creating a campaign.

Input parameters:

- `list_uid` (string, required)
- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_list_subscribers` (~80 tokens)

List subscribers

List the subscribers of a mailing list (sets of 10 per page; use page to go on). Contains personal data (emails, names).

Input parameters:

- `list_uid` (string, required)
- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_get_subscriber` (~62 tokens)

Get a subscriber

Get one subscriber of a list by subscriber uid (status, fields, dates).

Input parameters:

- `list_uid` (string, required)
- `subscriber_uid` (string, required): Subscriber uid from mailblaze_list_subscribers or mailblaze_find_subscriber_by_email.

### `mailblaze_find_subscriber_by_email` (~54 tokens)

Find a subscriber by email

Look up a subscriber in one list by email address. Returns the subscriber (with its uid) or a not-found error.

Input parameters:

- `email` (string, required)
- `list_uid` (string, required)

### `mailblaze_add_subscriber` (~156 tokens)

Add a subscriber

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.

Input parameters:

- `custom_fields` (object): Custom field values keyed by the field's tag (see mailblaze_list_list_fields), e.g. {"PHONE": "+1 555 0100"}.
- `email` (string, required)
- `first_name` (string): Sets the FNAME field.
- `last_name` (string): Sets the LNAME field.
- `list_uid` (string, required)

### `mailblaze_add_subscribers_bulk` (~91 tokens)

Add or update subscribers in bulk

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.

Input parameters:

- `list_uid` (string, required)
- `subscribers` (array, required): 1 to 100 subscribers.

### `mailblaze_update_subscriber` (~138 tokens)

Update a subscriber

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.

Input parameters:

- `custom_fields` (object): Custom field values keyed by the field's tag (see mailblaze_list_list_fields), e.g. {"PHONE": "+1 555 0100"}.
- `email` (string, required): The subscriber's email (Mail Blaze requires it on update).
- `first_name` (string)
- `last_name` (string)
- `list_uid` (string, required)
- `subscriber_uid` (string, required)

### `mailblaze_unsubscribe_subscriber` (~89 tokens)

Unsubscribe a subscriber

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.

Input parameters:

- `list_uid` (string, required)
- `subscriber_uid` (string, required)

### `mailblaze_resubscribe_subscriber` (~62 tokens)

Resubscribe a subscriber

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).

Input parameters:

- `list_uid` (string, required)
- `subscriber_uid` (string, required)

### `mailblaze_list_templates` (~63 tokens)

List email templates

List the account's email templates (uid, name). A template uid is needed to create a campaign.

Input parameters:

- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_get_template` (~30 tokens)

Get an email template

Get one email template by uid (name and content).

Input parameters:

- `template_uid` (string, required)

### `mailblaze_create_template` (~68 tokens)

Create an email template

WRITE: create an email template from HTML (the tool base64-encodes it). Mail Blaze requires the HTML to contain an unsubscribe link. Sends nothing.

Input parameters:

- `html` (string, required): The full HTML of the email, including an unsubscribe link.
- `name` (string, required)

### `mailblaze_list_campaigns` (~67 tokens)

List campaigns

List the account's email campaigns (uid, name, status, dates). Use the campaign uid for details and reports.

Input parameters:

- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_get_campaign` (~37 tokens)

Get a campaign

Get one campaign by uid: sender, subject, list, template, status and schedule.

Input parameters:

- `campaign_uid` (string, required)

### `mailblaze_create_campaign` (~226 tokens)

Create and schedule a campaign

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).

Input parameters:

- `from_email` (string, required): Sender address; it must be a verified sender in Mail Blaze.
- `from_name` (string, required)
- `list_uid` (string, required)
- `name` (string, required): Internal campaign name.
- `reply_to` (string, required)
- `segment_uid` (string): Send only to this segment of the list.
- `send_at` (string, required): When to send, 'YYYY-MM-DD HH:MM:SS' (interpreted by Mail Blaze in the account's time zone).
- `subject` (string, required)
- `template_uid` (string, required)

### `mailblaze_get_campaign_summaries` (~75 tokens)

Get campaign report summaries

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).

Input parameters:

- `campaign_uids` (array, required): 1 to 50 campaign uids.

### `mailblaze_get_campaign_inbox_breakdown` (~42 tokens)

Get a campaign's inbox breakdown

Inbox-provider breakdown (e.g. Gmail, Outlook, Yahoo) of a campaign's delivery.

Input parameters:

- `campaign_uid` (string, required)

### `mailblaze_list_campaign_events` (~134 tokens)

List a campaign's opens, clicks, bounces or unsubscribes

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.

Input parameters:

- `campaign_uid` (string, required)
- `cursor` (string): The next_cursor from the previous reply, passed back exactly as returned. Omit for the first page.
- `kind` (string, required)
- `limit` (integer): Events per page (default 100, max 1000).

### `mailblaze_get_subscriber_activity` (~104 tokens)

Get a subscriber's activity

Email activity (sends, opens, clicks, bounces) of one subscriber by email address, optionally limited to one list. Cursor-paged.

Input parameters:

- `cursor` (string): The next_cursor from the previous reply, passed back exactly as returned. Omit for the first page.
- `email` (string, required)
- `limit` (integer): Events per page (default 100, max 1000).
- `list_uid` (string)

### `mailblaze_get_report_job` (~45 tokens)

Get a report job's status

Status (and result when finished) of an asynchronous report job, as returned in a 202 reply with a job_id.

Input parameters:

- `job_id` (string, required)

### `mailblaze_list_transactional_emails` (~65 tokens)

List transactional emails

List the transactional emails sent through the account (uid, recipient, subject, status). Paged.

Input parameters:

- `page` (integer): Page number, starting at 1 (results come in sets of 10; keep going until a page comes back empty).

### `mailblaze_get_transactional_email` (~36 tokens)

Get a transactional email

Get one transactional email by uid: recipient, subject, status and timestamps.

Input parameters:

- `email_uid` (string, required)

### `mailblaze_send_transactional_email` (~249 tokens)

Send a transactional email

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.

Input parameters:

- `from_email` (string, required): Sender address; it must be a verified sender in Mail Blaze.
- `from_name` (string, required): 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, required)
- `template_id` (string): Transactional template id. Omit when sending html.
- `to_email` (string, required)
- `to_name` (string, required): Recipient name (required by Mail Blaze).

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze#diagnostics

## Score history

- 2026-10-25: 61

## Common questions

### 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.

## Links

- Remote endpoint: https://mailblaze.usefulapi.io/mcp
- Repository: https://github.com/m190/usefulapi-mcp
- Website: https://usefulapi.io/mailblaze/
- Changelog RSS feed: https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze.xml
- Changelog JSON feed: https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze.json
- HTML version of this page: https://verifymcp.io/servers/io-usefulapi-mailblaze/mailblaze