# MailBluster MCP by usefulapi (remote · mailbluster.usefulapi.io)

Manage MailBluster leads, custom fields, products and orders: look up, add and update records.

- Trust score: 64/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-17

## Components

- remote · `mailbluster.usefulapi.io`: 64/100 (this document), [markdown](https://verifymcp.io/servers/io-usefulapi-mailbluster/mailbluster.md), [page](https://verifymcp.io/servers/io-usefulapi-mailbluster/mailbluster)

## Channel facts

- Endpoint: `https://mailbluster.usefulapi.io/mcp`
- Transports: `streamable-http`
- Auth: `required`
- Version: `1.0.0`

## 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 2026-10-17.

- **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 1779 tokens (~136/item across 13 items; 13 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 17/100
  - Stability observed for 5 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 94/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 82% 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.
  - We read all 13 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 14 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 MailBluster MCP by usefulapi server?

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

### Cursor

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

### VS Code

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

### Codex

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

### opencode

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

### OpenClaw

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

### Hermes

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

### Netclaw

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

### Vellum

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

### Other

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

### 2026-10-16 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-10-14 (score 63, +2)

- [security] The server rewrote its instructions, which are the text every model session reads
- [functional] 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

### 2026-10-13 (score 61, +1)

- [functional improvement] Stability: unverified → 0.03

### 2026-10-12 (score 60)

First indexed and scored.

## MCP tools (13)

### `mailbluster_list_fields` (~46 tokens)

List custom lead fields

List the brand's custom lead fields: id, label and merge tag. Use the merge tags as keys of `fields` when creating or updating leads. GET /fields.

### `mailbluster_create_field` (~84 tokens)

Create custom lead field

WRITE: create a custom lead field. The merge tag is the key used in lead `fields` and in email templates. Creating a field changes the brand's data model but sends nothing. POST /fields.

Input parameters:

- `field_label` (string, required): Display label, e.g. Gender.
- `field_merge_tag` (string, required): Merge tag, e.g. gender.

### `mailbluster_get_lead` (~110 tokens)

Get lead

Get one lead by email address (the server computes the MD5 id MailBluster uses): name, custom fields, timezone, subscribed and opt-in status, tags, created/updated dates. MailBluster has no list-leads endpoint. GET /leads/{md5(email)}.

Input parameters:

- `email` (string): The lead's email address (preferred).
- `lead_hash` (string): Alternative to email: the 32-character MD5 hex of the lowercased email.

### `mailbluster_create_lead` (~288 tokens)

Create lead

WRITE: add a lead (contact) to the brand. `subscribed` defaults to FALSE: the lead is stored but is not subscribed to email. Only set subscribed=true when the person has given consent to receive email from this brand (the user is responsible for lawful consent); this server never subscribes anyone on its own. No email is sent by this tool (double opt-in is not offered). If the lead already exists the call fails unless overwrite_existing=true, which replaces the stored data (then `subscribed` must be given explicitly). POST /leads.

Input parameters:

- `email` (string, required): Email address.
- `fields` (object): Custom field values keyed by the field's MERGE TAG (see mailbluster_list_fields), e.g. {"company": "Pied Piper"}.
- `first_name` (string)
- `ip_address` (string): Lead's IP address; MailBluster derives country/city/timezone from it.
- `last_name` (string)
- `overwrite_existing` (boolean): Default false. true overwrites an existing lead with the same email.
- `subscribed` (boolean): Default false. true only with the lead's consent to receive email.
- `tags` (array): Tag names to attach (created if missing).
- `timezone` (string): IANA timezone, e.g. America/Los_Angeles.

### `mailbluster_update_lead` (~292 tokens)

Update lead

WRITE: change an existing lead's name, custom fields, email, timezone, IP address, subscription flag or tags (send only what should change). `subscribed` is left alone unless you pass it; false unsubscribes the lead, true re-subscribes. Only set subscribed=true when the person has given consent to receive email from this brand (the user is responsible for lawful consent); this server never subscribes anyone on its own. PUT /leads/{md5(email)}.

Input parameters:

- `add_tags` (array): Tag names to attach (created if missing). Applied before remove_tags.
- `email` (string): Current email of the lead to update (preferred).
- `fields` (object): Custom field values keyed by the field's MERGE TAG (see mailbluster_list_fields), e.g. {"company": "Pied Piper"}.
- `first_name` (string)
- `ip_address` (string)
- `last_name` (string)
- `lead_hash` (string): Alternative to email: the 32-character MD5 hex of the lowercased current email.
- `new_email` (string): Change the lead's email address to this.
- `remove_tags` (array): Tag names to detach.
- `subscribed` (boolean): Only pass to change the subscription. true only with the lead's consent.
- `timezone` (string)

### `mailbluster_list_products` (~105 tokens)

List products

List product records (id, name, dates) the brand has registered for e-commerce tracking. Paged: the reply's meta has total and nextPageNo (null on the last page). GET /products.

Input parameters:

- `page_no` (integer): Page number, from 1 (default 1). Pass the previous reply's meta.nextPageNo.
- `per_page` (integer): Results per page, 1-100 (MailBluster default 10).

### `mailbluster_get_product` (~40 tokens)

Get product

Get one product record by the id you registered it under. GET /products/{product_id}.

Input parameters:

- `product_id` (string, required): Product id.

### `mailbluster_create_product` (~64 tokens)

Create product

WRITE: register a product record (your own id plus a name) so orders can reference it. Sends nothing to anyone and charges nothing. POST /products.

Input parameters:

- `name` (string, required): Product name.
- `product_id` (string, required): Your unique product id.

### `mailbluster_update_product` (~45 tokens)

Update product

WRITE: rename a product record. PUT /products/{product_id}.

Input parameters:

- `name` (string, required): New product name.
- `product_id` (string, required): Product id.

### `mailbluster_list_orders` (~110 tokens)

List orders

List order records (id, currency, total price, customer lead, campaign, line items). These are records kept in MailBluster for tracking; no payment is involved. Paged: see meta.nextPageNo. GET /orders.

Input parameters:

- `page_no` (integer): Page number, from 1 (default 1). Pass the previous reply's meta.nextPageNo.
- `per_page` (integer): Results per page, 1-100 (MailBluster default 10).

### `mailbluster_get_order` (~40 tokens)

Get order

Get one order record by the id it was created with. GET /orders/{order_id}.

Input parameters:

- `order_id` (string, required): Order id.

### `mailbluster_create_order` (~217 tokens)

Create order record

WRITE: record an order (a tracking record: it does not take payment, charge a card or send email). The customer's email becomes a lead if none exists, and the lead's tags are merged. `customer.subscribed` is REQUIRED because MailBluster would otherwise default it to true: pass false unless the customer has consented to email. For a customer who already exists, the value may replace their stored subscription state. Only set subscribed=true when the person has given consent to receive email from this brand (the user is responsible for lawful consent); this server never subscribes anyone on its own. POST /orders.

Input parameters:

- `campaign_id` (integer): Id of the campaign that led to the order, if any.
- `currency` (string, required): ISO currency code, e.g. USD.
- `customer` (object, required)
- `items` (array, required): Ordered products.
- `order_id` (string, required): Your unique order id.
- `total_price` (number, required): Order total, e.g. 10.64.

### `mailbluster_update_order` (~126 tokens)

Update order record

WRITE: change an order record's campaign, currency, total or items (send only what should change; `items`, when given, REPLACES all previous items). The customer cannot be changed here. No payment or email is involved. PUT /orders/{order_id}.

Input parameters:

- `campaign_id` (integer)
- `currency` (string): ISO currency code, e.g. USD.
- `items` (array): New complete item list; replaces the previous items.
- `order_id` (string, required): Order id.
- `total_price` (number): New order total.

## Diagnostics

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

## Score history

- 2026-10-17: 64
- 2026-10-16: 64
- 2026-10-15: 63
- 2026-10-14: 63
- 2026-10-13: 61
- 2026-10-12: 60

## Common questions

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

MailBluster MCP by usefulapi is listed in the public MCP registry as io.usefulapi/mailbluster. Manage MailBluster leads, custom fields, products and orders: look up, add and update records. This page covers its hosted endpoint (https://mailbluster.usefulapi.io/mcp).

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

MailBluster 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 MailBluster MCP by usefulapi server expose?

MailBluster MCP by usefulapi exposes 13 tools: mailbluster_list_fields, mailbluster_create_field, mailbluster_get_lead, mailbluster_create_lead, mailbluster_update_lead, and 8 more. Their descriptions and schemas cost roughly 1,567 tokens of context every time the server is loaded.

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

Yes. MailBluster 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 MailBluster MCP by usefulapi server still maintained?

MailBluster 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.

## Links

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