CLOSUM API

Name: CLOSUM API API
Brand: CLOSUM API
Availability: InStock

★ Only Publicly Available OpenAPI DocumentMarketingMarketing AutomationapiKey40 EndpointsREST

For Agents

Manage leads, contacts, tags, and email templates in Closum, send templated emails, and wire up automation webhooks.

Quickstart

Get started with CLOSUM API in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"add a lead to closum"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with CLOSUM API API.

Create and update leads with notes attached for sales handoff

Add and remove tags on contacts and leads by id or by email

List and edit custom contact fields used for segmentation

Send transactional emails by referencing a saved email template id

Create and update email templates programmatically

GET STARTED

Start building with CLOSUM API API

Explore with Jentic

View OpenAPI Document

Jentic publishes the only available OpenAPI document for CLOSUM API, keeping it validated and agent-ready.

Jentic publishes the only available OpenAPI specification for CLOSUM API, keeping it validated and agent-ready. Closum is an inbound marketing platform aimed at small and medium businesses, covering landing pages, newsletters, SMS marketing, and lightweight CRM. The v2 REST API exposes 40 operations across leads, contacts, tags, custom fields, email templates, automations, and webhooks. Authentication is an API key passed as a query parameter.

Use Cases

Patterns agents use CLOSUM API API for, with concrete tasks.

★ Form-to-CRM Lead Capture

SMB marketers pull leads in from landing pages, webinars, and ads and need them in Closum within seconds. POST /lead/add/ creates the lead, POST /lead/add-note/{lead_id} attaches the source context, and POST /contact-tag/add-lead-tag/{lead_id} applies a campaign tag. The flow eliminates the manual CSV upload step and keeps source attribution intact.

Create a lead with email maria@example.com and name 'Maria Lopez', attach a note 'Source: Q3 Webinar', and tag with 'Webinar-Q3'.

Tag-Based Segmentation by Email

Closum's PUT /lead/edit-by-email and POST /contact-tag/add-tag-by-email/ endpoints let an agent enrich and segment contacts using only the email address as a key — useful when integrating with external sources that do not expose Closum ids. Agents can sync ESP-style tags from external systems without resolving ids first.

Apply the tag 'High-Intent' to the contact whose email is jess@example.com and remove the tag 'Newsletter-Only'.

Templated Transactional Sends

POST /email-template/send/{template_id} fires a saved template against a recipient, while POST /email-template/create/ and /email-template/update/ keep the template library current. This lets ops teams treat Closum like a transactional sender for a small set of recurring templates without paying for a separate ESP.

Send template 1234 to contact_id 5678 with the variable 'first_name' set to 'Maria'.

AI Agent Marketing Concierge

Embed Closum into an AI assistant that small business owners can chat with — 'add this lead, tag them, send the welcome email'. Through Jentic, the agent searches by intent, loads the right operation, and executes against Closum. The query-string API key lives in the Jentic vault and never enters the model context.

Search Jentic for 'add lead to closum', load the schema, and execute it for a new lead captured from a Google Form submission.

Key Endpoints

40 endpoints — jentic publishes the only available openapi specification for closum api, keeping it validated and agent-ready.

METHOD

PATH

DESCRIPTION

POST

/lead/add/

Create a lead

PUT

/lead/edit-by-email

Update a lead by email

POST

/contact/add

Create a contact

POST

/contact-tag/add-tag-by-email/

Tag a contact by email

POST

/email-template/send/{template_id}

Send a saved email template

GET

/tag/

List tags

GET

/field/

List custom contact fields

POST

/lead/add/

Create a lead

PUT

/lead/edit-by-email

Update a lead by email

POST

/contact/add

Create a contact

POST

/contact-tag/add-tag-by-email/

Tag a contact by email

POST

/email-template/send/{template_id}

Send a saved email template

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Closum query-string API keys are stored encrypted in the Jentic vault (MAXsystem). Jentic injects the key as a URL parameter at request time so agents never see the secret in their context.

Intent-based discovery

Agents search Jentic by intent (e.g., 'tag a closum contact by email') and Jentic returns the matching operation with its schema, so the agent skips reading the 40-endpoint reference.

Time to first call

Direct Closum integration: 1-2 days for auth, lead vs contact distinctions, and tag operations. Through Jentic: under 30 minutes — search, load, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Alternative

Close CRM API

Higher-end sales CRM with built-in calling and sequences for inside sales teams.

Choose Close when the team needs power-dialer, multi-step sequences, and deeper sales activity tracking; choose Closum for lighter-weight SMB marketing-led CRM.

Complementary

Cloro API

AI answer engine monitoring API to feed visibility data into Closum campaigns.

Use Cloro to detect drops in AI answer-engine visibility, then trigger Closum email campaigns to address them.

Complementary

Clockify API

Time tracking API for marketing teams running Closum campaigns.

Use Clockify to track marketing time spent on Closum campaign builds and report it back to clients.

FAQs

Specific to using CLOSUM API API through Jentic.

Why is there no official OpenAPI spec for CLOSUM API?

Closum does not publish an OpenAPI specification — only narrative developer docs. Jentic generates and maintains this spec so that AI agents and developers can call CLOSUM API via structured tooling. It is validated against the live API and kept up to date. Get started at https://app.jentic.com/sign-up.

What authentication does the Closum API use?

Closum uses an API key passed as a query parameter on each request. Generate the key from your account settings. Through Jentic, the key is stored encrypted in the MAXsystem vault and appended to the URL at execution time so agents never see it.

Can I tag contacts by email address with the Closum API?

Yes. POST /contact-tag/add-tag-by-email/ accepts an email and tag pair, so you do not need to resolve the contact id first. DELETE /contact-tag/remove-tag-by-email/ does the inverse. Both are useful for syncing tags from external sources keyed on email.

What are the rate limits for the Closum API?

Closum applies plan-based rate limits, typically a few requests per second per account. Exact limits are not encoded in the spec — handle 429 responses with backoff. Jentic surfaces 429s back to the agent for clean retries.

How do I send a templated email through Jentic?

Run pip install jentic, search for 'send closum email template', load the POST /email-template/send/{template_id} schema, and execute with template_id and contact_id. Variables in the template are passed in the request body.

Does the Closum API support custom fields?

Yes. GET /field/ lists the custom contact fields configured for the account; you can then reference these fields when creating or editing contacts. This lets you persist segmentation attributes that aren't part of the default contact schema.