Customer.io MCP by usefulapi
REMOTE · CUSTOMERIO.USEFULAPI.IO
Query people, segments, campaigns, and message deliveries; send transactional email or broadcasts.
Available components
Last scanned (46 minutes ago)
Scores higher than 4% of remote servers
Reachable. Last reached 5 Nov 2026.
Category Marketing and SEO
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 Security46
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not yet verified: we couldn't confirm whether this endpoint requires it. View diagnostics → Unverified
- 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
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 Usability0
- Schema not yet verified: we couldn't read the endpoint's schema, or could read only part of its tool list.Unverified
Stability & Change Management0
- Stability not yet verified: not enough scan history yet (needs a 30-day window).Unverified
Tool Coverage0
- Tool coverage not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.Unverified
Tool Safety0
- Tool safety not yet verified: we couldn't read the endpoint's tools, or could read only part of the list.Unverified
Capabilities0
- Capabilities not yet verified: we couldn't read the endpoint's capabilities.Unverified
Unverified: 5 categories
Categories scored 0 because we could not verify them: 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.
- 1 Nov 26 −62
- Endpoint reachability: reachable → not serving MCP ▼ security
- Stability: pass → unverified ▼ security
- Tool safety: pass → unverified ▼ security
- Authorization: pass → unverified ▼ security
- Schema quality: 100 → unverified ▼ functional
- Capabilities: pass → unverified ▼ functional
- Tool coverage: 100 → unverified ▼ functional
- 31 Oct 26 +3
- Authorization: partial → pass ▲ security
- MCP protocol: fail → pass ▲ functional
- New prompt “check_how_a_campaign_performed” functional
- New prompt “list_the_people_in_a_segment” functional
- New prompt “review_recent_deliveries_across_the_workspace” functional
- New prompt “see_what_a_person_received” functional
- New prompt “send_a_transactional_email_or_trigger_a_broadcast” functional
- MCP protocol version: 2025-06-18 → 2025-11-25 functional
- Server version: 1.31.0 → 1.33.0 functional
- Server version: 1.30.0 → 1.31.0 functional
- Server version: 1.29.2 → 1.30.0 functional
- 30 Oct 26 0
- Server version: 1.29.1 → 1.29.2 functional
- Server version: 1.29.0 → 1.29.1 functional
- 29 Oct 26 0
- Server version: 1.28.0 → 1.29.0 functional
- Server version: 1.27.0 → 1.28.0 functional
- 28 Oct 26 0
- Server version: 1.25.0 → 1.27.0 functional
- 27 Oct 26 0
- Server version: 1.24.0 → 1.25.0 functional
- 25 Oct 26 0
- Server version: 1.23.0 → 1.24.0 functional
- Server version: 1.22.0 → 1.23.0 functional
- Server version: 1.21.3 → 1.22.0 functional
- Server version: 1.21.1 → 1.21.3 functional
- Server version: 1.21.0 → 1.21.1 functional
- 24 Oct 26 0
- The server rewrote its instructions, which are the text every model session reads security
- Server version: 1.20.0 → 1.21.0 functional
- Server version: 1.19.0 → 1.20.0 functional
- Server version: 1.17.0 → 1.19.0 functional
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 5 Nov 2026 · Probed https://customerio.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 customerio.usefulapi.io. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| io. | present | 38690 | 8 | Verified |
| usefulapi.io. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication Inconclusive
We could not reach the endpoint well enough to judge its authorisation posture.
| Result | Inconclusive |
|---|---|
| HTTP status | 302 |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://customerio.usefulapi.io/mcp | Redirected | 302 | https://usefulapi.io/customerio/ |
| http (plaintext) | http://customerio.usefulapi.io/mcp | Inconclusive | 302 | http://customerio.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 →
customerio_get_campaign Get campaign ~43
Get a single campaign by id. App API: GET /v1/campaigns/{campaign_id}.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_id | string|number | yes | Campaign id. |
No output schema declared.
No examples provided.
customerio_get_campaign_metrics Get campaign metrics ~94
Get delivery/engagement metrics for a campaign over time. App API: GET /v1/campaigns/{campaign_id}/metrics.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_id | string|number | yes | Campaign id. |
| period | string | – | Bucket size. Default days. |
| steps | integer | – | Number of periods to return. |
| type | string | – | Metric type filter (e.g. email, push, sms). |
No output schema declared.
No examples provided.
customerio_get_customer_attributes Get customer attributes ~57
Get a single person's attributes (profile fields). App API: GET /v1/customers/{customer_id}/attributes.
| Name | Type | Req | Description |
|---|---|---|---|
| customer_id | string | yes | The person's id (or cio_id / email, per your identifier setup). |
No output schema declared.
No examples provided.
customerio_get_customer_messages Get customer messages ~76
List messages (deliveries) sent to a single person. App API: GET /v1/customers/{customer_id}/messages.
| Name | Type | Req | Description |
|---|---|---|---|
| customer_id | string | yes | The person's id. |
| limit | integer | – | Max messages to return. |
| start | string | – | Pagination cursor from a previous response's `next`. |
No output schema declared.
No examples provided.
customerio_get_customer_segments Get customer segments ~46
List the segments a single person belongs to. App API: GET /v1/customers/{customer_id}/segments.
| Name | Type | Req | Description |
|---|---|---|---|
| customer_id | string | yes | The person's id. |
No output schema declared.
No examples provided.
customerio_list_campaigns List campaigns ~29
List all campaigns in the workspace. App API: GET /v1/campaigns.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
customerio_list_collections List collections ~29
List reusable data collections in the workspace. App API: GET /v1/collections.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
customerio_list_exports List exports ~27
List data exports in the workspace. App API: GET /v1/exports.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
customerio_list_messages List messages ~134
List sent messages (deliveries) across the workspace, filterable by type/campaign/newsletter. App API: GET /v1/messages.
| Name | Type | Req | Description |
|---|---|---|---|
| campaign_id | string|number | – | Filter to a specific campaign. |
| drafts | boolean | – | Include drafts. |
| limit | integer | – | Max messages to return. |
| newsletter_id | string|number | – | Filter to a specific newsletter. |
| start | string | – | Pagination cursor from a previous response's `next`. |
| type | string | – | Message type filter, e.g. email | push | sms | in_app | webhook | slack | twilio. |
No output schema declared.
No examples provided.
customerio_list_segments List segments ~33
List all segments in the workspace (id + name + type). App API: GET /v1/segments.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
customerio_search_customers Search customers ~117
Search/list people by a Customer.io filter (segment or attribute conditions). e.g. filter={"segment":{"id":7}} or {"and":[...]}. App API: POST /v1/customers.
| Name | Type | Req | Description |
|---|---|---|---|
| filter | object | yes | Customer.io filter object, e.g. {"segment":{"id":7}} or {"and":[{"attribute":{"field":"email","operator":"exists"}}]}. |
| limit | integer | – | Max people to return. |
| start | string | – | Pagination cursor from a previous response's `next`. |
No output schema declared.
No examples provided.
customerio_send_transactional_email Send transactional email ~195
⚠️ SENDS A REAL EMAIL. Send a transactional email using a transactional message template. Delivers immediately to the `to` recipient. App API: POST /v1/send/email.
| Name | Type | Req | Description |
|---|---|---|---|
| body | string | – | Override the email body. |
| disable_message_retention | boolean | – | If true, don't retain the message body. |
| from | string | – | Override the sender address. |
| identifiers | object | yes | Person identifiers, e.g. {"id":"..."} or {"email":"..."}. |
| message_data | object | – | Template variables (liquid) to interpolate into the message. |
| send_to_unsubscribed | boolean | – | If true, send even to unsubscribed recipients. |
| subject | string | – | Override the subject line. |
| to | string | yes | Recipient email address. |
| transactional_message_id | string|number | yes | The transactional message template id (or trigger name). |
No output schema declared.
No examples provided.
customerio_trigger_broadcast Trigger broadcast ~160
⚠️ SENDS TO REAL RECIPIENTS. Trigger an API-triggered broadcast, delivering to the resolved recipient set. App API: POST /v1/send/broadcast (posts to /v1/campaigns/{broadcast_id}/triggers).
| Name | Type | Req | Description |
|---|---|---|---|
| broadcast_id | string|number | yes | The API-triggered broadcast id. |
| data | object | – | Liquid variables available to the broadcast templates. |
| email_add_duplicates | boolean | – | Allow duplicate email recipients. |
| email_ignore_missing | boolean | – | Skip recipients missing an email instead of erroring. |
| id_ignore_missing | boolean | – | Skip recipients missing an id instead of erroring. |
| recipients | object | – | Recipient filter object (overrides the broadcast's configured audience). |
No output schema declared.
No examples provided.
How do I install the Customer.io MCP by usefulapi server?
Customer.io MCP by usefulapi is a hosted endpoint at https://customerio.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 · customerio.usefulapi.io
claude mcp add --transport http io-usefulapi-customerio 'https://customerio.usefulapi.io/mcp'
What is the Customer.io MCP by usefulapi server?
Customer.io MCP by usefulapi is listed in the public MCP registry as io.usefulapi/customerio. Query people, segments, campaigns, and message deliveries; send transactional email or broadcasts. This page covers its hosted endpoint (https://customerio.usefulapi.io/mcp).
Is the Customer.io MCP by usefulapi server safe to use?
Customer.io MCP by usefulapi scores 18 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 Customer.io MCP by usefulapi server expose?
Customer.io MCP by usefulapi exposes 13 tools: customerio_search_customers, customerio_get_customer_attributes, customerio_get_customer_segments, customerio_get_customer_messages, customerio_list_segments, and 8 more. Their descriptions and schemas cost roughly 1,040 tokens of context every time the server is loaded.
Does the Customer.io MCP by usefulapi server require authentication?
Its publisher declares no required credentials for Customer.io MCP by usefulapi. We have not been able to confirm that against the live endpoint, and a server can require authorisation without declaring it here.
Is the Customer.io MCP by usefulapi server still maintained?
Customer.io MCP by usefulapi is still listed as active in the MCP registry. We last reached this channel on 5 November 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.