MailBluster MCP by usefulapi
REMOTE · MAILBLUSTER.USEFULAPI.IO
Manage MailBluster leads, custom fields, products and orders: look up, add and update records.
Available components
Last scanned (8 hours 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 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
- 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. 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 Coverage94
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 82% 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
- We read all 13 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 14 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.
- 16 Oct 26 +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.
- 14 Oct 26 +2
- 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 +1
- 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://mailbluster.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 mailbluster.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://mailbluster.usefulapi.io/.well-known/oauth-protected-resource/mcp"
Bearer realm="OAuth", resource_metadata="https://mailbluster.usefulapi.io/.well-known/oauth-protected-resource/mcp"Protected resource metadata
| Document | https://mailbluster.usefulapi.io/.well-known/oauth-protected-resource/mcp |
|---|---|
| Retrieved | Yes |
| Resource | https://mailbluster.usefulapi.io/mcp |
| Authorisation server | https://mailbluster.usefulapi.io |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://mailbluster.usefulapi.io/mcp | Redirected | 302 | https://usefulapi.io/mailbluster/ |
| http (plaintext) | http://mailbluster.usefulapi.io/mcp | Inconclusive | 302 | http://mailbluster.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 →
mailbluster_create_field Create custom lead field ~84
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.
| Name | Type | Req | Description |
|---|---|---|---|
| field_label | string | yes | Display label, e.g. Gender. |
| field_merge_tag | string | yes | Merge tag, e.g. gender. |
No output schema declared.
No examples provided.
mailbluster_create_lead Create lead ~288
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.
| Name | Type | Req | Description |
|---|---|---|---|
| string | yes | 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. |
No output schema declared.
No examples provided.
mailbluster_create_order Create order record ~217
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.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_id | integer | – | Id of the campaign that led to the order, if any. |
| currency | string | yes | ISO currency code, e.g. USD. |
| customer | object | yes | – |
| items | array | yes | Ordered products. |
| order_id | string | yes | Your unique order id. |
| total_price | number | yes | Order total, e.g. 10.64. |
No output schema declared.
No examples provided.
mailbluster_create_product Create product ~64
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.
| Name | Type | Req | Description |
|---|---|---|---|
| name | string | yes | Product name. |
| product_id | string | yes | Your unique product id. |
No output schema declared.
No examples provided.
mailbluster_get_lead Get lead ~110
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)}.
| Name | Type | Req | Description |
|---|---|---|---|
| string | – | The lead's email address (preferred). | |
| lead_hash | string | – | Alternative to email: the 32-character MD5 hex of the lowercased email. |
No output schema declared.
No examples provided.
mailbluster_get_order Get order ~40
Get one order record by the id it was created with. GET /orders/{order_id}.
| Name | Type | Req | Description |
|---|---|---|---|
| order_id | string | yes | Order id. |
No output schema declared.
No examples provided.
mailbluster_get_product Get product ~40
Get one product record by the id you registered it under. GET /products/{product_id}.
| Name | Type | Req | Description |
|---|---|---|---|
| product_id | string | yes | Product id. |
No output schema declared.
No examples provided.
mailbluster_list_fields List custom lead fields ~46
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.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
mailbluster_list_orders List orders ~110
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.
| Name | Type | Req | Description |
|---|---|---|---|
| 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). |
No output schema declared.
No examples provided.
mailbluster_list_products List products ~105
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.
| Name | Type | Req | Description |
|---|---|---|---|
| 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). |
No output schema declared.
No examples provided.
mailbluster_update_lead Update lead ~292
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)}.
| Name | Type | Req | Description |
|---|---|---|---|
| add_tags | array | – | Tag names to attach (created if missing). Applied before remove_tags. |
| 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 | – | – |
No output schema declared.
No examples provided.
mailbluster_update_order Update order record ~126
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}.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_id | integer | – | – |
| currency | string | – | ISO currency code, e.g. USD. |
| items | array | – | New complete item list; replaces the previous items. |
| order_id | string | yes | Order id. |
| total_price | number | – | New order total. |
No output schema declared.
No examples provided.
mailbluster_update_product Update product ~45
WRITE: rename a product record. PUT /products/{product_id}.
| Name | Type | Req | Description |
|---|---|---|---|
| name | string | yes | New product name. |
| product_id | string | yes | Product id. |
No output schema declared.
No examples provided.
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.
remote · mailbluster.usefulapi.io
claude mcp add --transport http io-usefulapi-mailbluster 'https://mailbluster.usefulapi.io/mcp'
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.