# Enginemailer MCP by usefulapi (remote · enginemailer.usefulapi.io)

Read Enginemailer subscribers, lists and campaigns; add subscribers, create and send campaigns.

- Trust score: 62/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-25

## Components

- remote · `enginemailer.usefulapi.io`: 62/100 (this document), [markdown](https://verifymcp.io/servers/io-usefulapi-enginemailer/enginemailer.md), [page](https://verifymcp.io/servers/io-usefulapi-enginemailer/enginemailer)

## Channel facts

- Endpoint: `https://enginemailer.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).
  - Context-footprint check failed: tool/resource definitions use about 2141 tokens (~125/item across 17 items; 17 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 3/100
  - Stability observed for 1 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 93/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 78% 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 2 tool(s) whose name or description implies an irreversible operation declare an MCP destructiveHint annotation.
  - An AI judge read all 18 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.

## Install

### How do I install the Enginemailer MCP by usefulapi server?

Enginemailer MCP by usefulapi is a hosted endpoint at https://enginemailer.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-enginemailer 'https://enginemailer.usefulapi.io/mcp'
```

### Cursor

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

### VS Code

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

### Codex

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

### opencode

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

### OpenClaw

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

### Hermes

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

### Netclaw

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

### Vellum

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

### Other

```json
{
  "mcpServers": {
    "io-usefulapi-enginemailer": {
      "type": "http",
      "url": "https://enginemailer.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 62, 0)

- [functional improvement] Stability: unverified → 0.03
- [functional] Server version: 1.0.1 → 1.0.3
- [functional] Server version: 1.0.0 → 1.0.1

### 2026-10-24 (score 62)

First indexed and scored.

## MCP tools (17)

### `enginemailer_get_subscriber` (~52 tokens)

Get subscriber

One subscriber by email: id, status and all custom field values. GET /restapi/subscriber/emsubscriber/getSubscriber.

Input parameters:

- `email` (string, required): An email address (max 128 characters).

### `enginemailer_list_subscriber_categories` (~83 tokens)

List subscriber categories

The subscriber category tree: each category with its subcategories (ids, names). Use the subcategory ids when adding or updating subscribers and when assigning campaign recipients. GET /restapi/subscriber/emsubscriber/getSubCategory.

Input parameters:

- `include_active_subscriber_count` (boolean): Also return active subscriber counts (only for accounts the vendor has enabled this for).

### `enginemailer_list_custom_fields` (~45 tokens)

List custom fields

The subscriber custom field definitions (key, name, type). Use the keys when adding or updating subscribers. GET /restapi/subscriber/emsubscriber/getCustomField.

### `enginemailer_add_subscriber` (~150 tokens)

Add subscriber

WRITE: add a subscriber to the account (optionally into subcategories, with custom field values). Only add people who consented to marketing email. Free accounts may insert 50 subscribers a day, paid accounts 10,000. POST /restapi/subscriber/emsubscriber/insertSubscriber.

Input parameters:

- `custom_fields` (array): Custom field values to set.
- `email` (string, required): An email address (max 128 characters).
- `source_type` (string): Where the subscriber came from, e.g. 'Signup from website' (max 256).
- `subcategory_ids` (array): Subcategory (list/segment) ids from enginemailer_list_subscriber_categories.

### `enginemailer_update_subscriber` (~186 tokens)

Update subscriber

WRITE: change an existing subscriber's subcategories and/or custom fields. subcategories_mode: append (default), remove (drop the given subcategories) or replace (the given list becomes the full list). custom_fields_mode: update_given (change only the given fields) or replace_all (default; fields not given are cleared). POST /restapi/subscriber/emsubscriber/updateSubscriber.

Input parameters:

- `custom_fields` (array): Custom field values to set.
- `custom_fields_mode` (string): update_given changes only the listed fields; replace_all (the vendor default) clears the others.
- `email` (string, required): An email address (max 128 characters).
- `subcategories_mode` (string): How subcategory_ids apply (default append).
- `subcategory_ids` (array): Subcategory (list/segment) ids from enginemailer_list_subscriber_categories.

### `enginemailer_unsubscribe_subscriber` (~68 tokens)

Unsubscribe subscriber

WRITE: unsubscribe a subscriber so they no longer receive campaigns. Reversing it needs the subscriber to opt in again in Enginemailer. GET /restapi/subscriber/emsubscriber/unSubSubscriber.

Input parameters:

- `email` (string, required): An email address (max 128 characters).

### `enginemailer_save_subscriber_category` (~119 tokens)

Create or update subscriber category

WRITE: create a subscriber category (category_id 0) or update one (its id), with subcategories (subcategory_id 0 creates one). Names and descriptions max 128 characters. POST /restapi/subscriber/emsubscriber/updateCategory.

Input parameters:

- `category_id` (integer, required): 0 to create a new category, else the existing category id.
- `description` (string)
- `is_visible` (boolean): Visible to subscribers (default true).
- `name` (string, required)
- `subcategories` (array)

### `enginemailer_list_campaigns` (~74 tokens)

List undelivered campaigns

List campaigns that have NOT been delivered yet (drafts and scheduled ones): id, name, subject, sender and schedule. Delivered campaigns are not listed by the API; use enginemailer_get_campaign_stats with a known id. Needs a paid account. GET /restapi/campaign/emcampaign/ListCampaign.

### `enginemailer_get_campaign_stats` (~79 tokens)

Get campaign delivery stats

Delivery results of a DELIVERED campaign: emails sent, delivered, bounces, opens, unique opens, clicks, unique clicks, unsubscribes, spam complaints. Needs a paid account. GET /restapi/campaign/emcampaign/getcampaigndeliverystatus.

Input parameters:

- `campaign_id` (integer, required): Campaign id.

### `enginemailer_list_campaign_categories` (~45 tokens)

List campaign categories

The categories that campaign recipients can be filtered by (id, name, description). Needs a paid account. GET /restapi/campaign/emcampaign/GetCategoryList.

### `enginemailer_list_campaign_subcategories` (~75 tokens)

List campaign subcategories

The subcategories of one campaign category (id, name, description); use these ids in enginemailer_assign_campaign_recipients. Needs a paid account. GET /restapi/campaign/emcampaign/GetSubCategoryList.

Input parameters:

- `category_id` (integer, required): Category id from enginemailer_list_campaign_categories.

### `enginemailer_create_campaign` (~152 tokens)

Create campaign (draft)

WRITE: create a campaign DRAFT. Nothing is sent: assign recipients with enginemailer_assign_campaign_recipients, then send with enginemailer_send_campaign. The sender domain must be verified in Enginemailer; max 200 campaigns per account. Needs a paid account. POST /restapi/Campaign/EMCampaign/CreateCampaign.

Input parameters:

- `content_html` (string, required): The email body, HTML (max 256 KB).
- `name` (string, required): Internal campaign name.
- `reply_to` (string): An email address (max 128 characters).
- `sender_email` (string, required): Sender address on a verified domain.
- `sender_name` (string, required)
- `subject` (string, required)

### `enginemailer_assign_campaign_recipients` (~131 tokens)

Assign campaign recipients

WRITE: set who a campaign will go to: all subscribers, or the subscribers in the given subcategory ids (match_type any = OR, all = AND). Does not send anything. Needs a paid account. POST /restapi/campaign/emcampaign/AssignRecipientList.

Input parameters:

- `audience` (string, required)
- `campaign_id` (integer, required): Campaign id.
- `match_type` (string): any = subscribers in at least one subcategory (OR, default); all = in every one (AND).
- `subcategory_ids` (array): Required when audience is subcategories.

### `enginemailer_send_campaign` (~122 tokens)

Send campaign NOW

WRITE, SENDS EMAIL TO CUSTOMERS NOW and cannot be undone: delivers the campaign to its assigned recipients immediately. The campaign needs at least one recipient and must not be scheduled or already delivered. Show the user the campaign and its audience and get their go-ahead first; set confirm to true only then. Needs a paid account. GET /restapi/campaign/emcampaign/SendCampaign.

Input parameters:

- `campaign_id` (integer, required): Campaign id.
- `confirm` (boolean, required): Must be true: the user has approved sending this campaign to its recipients now.

### `enginemailer_send_transactional_email` (~269 tokens)

Send transactional email

WRITE, SENDS ONE EMAIL NOW and cannot be undone: submits a transactional email to one recipient (plus optional CC/BCC). Needs a sender address on a verified domain; give either subject + content_html, or a template_id from the Enginemailer portal (the template supplies subject and sender name). Total message incl. attachments max 5 MB. Confirm the recipient and text with the user first; set confirm to true only then. POST /RESTAPI/V2/Submission/SendEmail.

Input parameters:

- `bcc` (array)
- `campaign_name` (string): Label for reports.
- `cc` (array)
- `confirm` (boolean, required): Must be true: the user has approved sending this email now.
- `content_html` (string): Email body (HTML). Not needed with template_id.
- `sender_email` (string, required): Sender address on a verified domain (must match the template's sender when template_id is used).
- `sender_name` (string)
- `subject` (string)
- `substitution_tags` (array): Merge tags. Values must not contain { } [ ].
- `template_id` (string): Stored template id from the Enginemailer portal.
- `to_email` (string, required): An email address (max 128 characters).

### `enginemailer_start_transactional_report_export` (~149 tokens)

Start transactional report export

Start a CSV export of the transactional email delivery report for a period (start date at most 60 days back). Returns an export id; poll it with enginemailer_check_transactional_report_export. Creates a report file only; nothing is sent. POST /RESTAPI/V2/Submission/Report/Export.

Input parameters:

- `domain_filter` (string): Domain filter, sent as the vendor's DomainFilter (the sender domain in the vendor's report), e.g. example.com.
- `email_to_filter` (string): Only emails sent to this recipient.
- `period` (string, required): Date range exactly like '1 Sep 2026 - 16 Sep 2026'.

### `enginemailer_check_transactional_report_export` (~69 tokens)

Check transactional report export

Status of a report export (Processing or Complete); when complete it includes the CSV download URL. POST /RESTAPI/V2/Submission/Report/CheckExport (read-only).

Input parameters:

- `export_id` (integer, required): ExportID from enginemailer_start_transactional_report_export.

## Diagnostics

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

## Score history

- 2026-10-25: 62
- 2026-10-24: 62

## Common questions

### What is the Enginemailer MCP by usefulapi server?

Enginemailer MCP by usefulapi is listed in the public MCP registry as io.usefulapi/enginemailer. Read Enginemailer subscribers, lists and campaigns; add subscribers, create and send campaigns. This page covers its hosted endpoint (https://enginemailer.usefulapi.io/mcp).

### Is the Enginemailer MCP by usefulapi server safe to use?

Enginemailer MCP by usefulapi scores 62 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 Enginemailer MCP by usefulapi server expose?

Enginemailer MCP by usefulapi exposes 17 tools: enginemailer_get_subscriber, enginemailer_list_subscriber_categories, enginemailer_list_custom_fields, enginemailer_add_subscriber, enginemailer_update_subscriber, and 12 more. Their descriptions and schemas cost roughly 1,868 tokens of context every time the server is loaded.

### Does the Enginemailer MCP by usefulapi server require authentication?

Yes. Enginemailer 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 Enginemailer MCP by usefulapi server still maintained?

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