Close CRM API
★ Only Publicly Available OpenAPI DocumentCRMDeal Pipelinebasic131 EndpointsREST
For Agents
Create and update leads, contacts, opportunities, and activities in Close, run sequences, and read smart views for sales pipeline automation.
Use for: I want to create a new lead with two contacts in Close, Log a call activity for a lead from yesterday, Move an opportunity from Discovery to Proposal stage, Enrol a list of leads into a follow-up email sequence
Not supported: Does not handle marketing email blasts, support ticketing, or contract e-signature — use for sales CRM, lead management, and outbound cadences only.
Jentic publishes the only available OpenAPI specification for Close CRM API, keeping it validated and agent-ready. Close is a sales CRM aimed at high-velocity inside sales teams, combining lead and contact management with built-in calling, email sequences, SMS, and a power dialer. The API exposes 131 operations across leads, contacts, opportunities, activities (calls, emails, notes, meetings, SMS), pipelines, custom fields, sequences, smart views, and bulk actions. Authentication is HTTP Basic with the API key as the username.
Install Jentic One Beta
Connect the Close CRM API to your agent
Jentic One is a self-hosted execution layer for AI agents. It lets your agent call the Close CRM API, or any other public or private API you need. You set the rules, the agent never sees your credentials, and every call is logged.
Two steps, two machines. Install the instance in a safe environment, then register your agent from wherever it runs.
1
Step 1: Jentic One Host machine
# On the machine that will host your Jentic One instance:
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh2
Step 2: Agent machine
# On the machine where your agent runs (keep this separate from the instance):
curl -fsSL https://raw.githubusercontent.com/jentic/jentic-one/main/tools/install.sh | sh
jentic register # connects your agent to your Jentic One instanceJentic One is in public beta. The setup above keeps your agent separate from the instance, which is what you want before using real credentials: an agent running as the same OS user as Jentic One can read its stored keys directly. Just evaluating? A single local install is fine to start. See the secure deployment guide for the tiers.
Capabilities
What an agent can do with Close CRM API.
Create and update leads with multiple contacts, opportunities, and custom fields
Log calls, emails, notes, meetings, and SMS as activities against a lead
Move opportunities through pipeline stages with status updates
Enrol leads into multi-step email and SMS sequences
Query smart views to filter leads by saved sales criteria
Trigger bulk actions on filtered lead sets and track export jobs
Use Cases
Patterns agents use Close CRM API for, with concrete tasks.
★ Inbound Lead Routing and Enrichment
Inbound forms produce raw lead records that need enrichment, deduplication, and routing in seconds. POST /lead/ creates the lead, POST /contact/ attaches contacts, and PUT /lead/{id}/ patches the record with enrichment data and assigns the right user. The flow replaces brittle Zaps and lets sales engineering own the routing logic.
Create a lead for 'Acme Corp' with contact Jane Doe (jane@acme.com), assign to user U9, and set the lead_status to 'Working'.
Activity Logging from Calling and Email Tools
Reps using external dialers or email clients still need every touch logged in Close. POST /activity/call/ records a call with duration, direction, and notes; POST /activity/email/ logs an email; POST /activity/sms/ logs an SMS. This produces a complete activity timeline without forcing reps to switch tools.
Log a 12-minute outbound call for lead L42, with note 'Demo scheduled for 2026-06-15' and direction 'outbound'.
Sequence-Driven Outbound Cadences
Outbound teams run multi-step cadences that combine email, SMS, and call tasks. The Sequences endpoints let an agent enrol qualified leads from a smart view into the right cadence, while activity endpoints surface replies and call outcomes. Teams can codify their best playbook once and replay it across territories.
Pull all leads in the 'Q3 SMB Outbound' smart view and enrol them in the 'SMB 5-Step Outreach' sequence, starting tomorrow.
AI Agent Sales Co-Pilot
Pair Close with an AI assistant that summarises deals, drafts follow-ups, and books meetings. Through Jentic, the agent searches by intent, loads the right operation, and updates the CRM without seeing the rep's API key. The Basic auth credential lives in the Jentic vault and never enters the model context.
Search Jentic for 'log a close email activity', load the schema, and execute it for a follow-up email to lead L42.
Key Endpoints
131 endpoints — jentic publishes the only available openapi specification for close crm api, keeping it validated and agent-ready.
METHOD
PATH
DESCRIPTION
POST
/lead/
Create a lead
GET
/lead/{id}/
Retrieve a lead by id
PUT
/lead/{id}/
Update a lead
POST
/contact/
Create a contact
POST
/activity/call/
Log a call activity
POST
/activity/email/
Log an email activity
POST
/activity/note/
Add a note to a lead
POST
/lead/
Create a lead
GET
/lead/{id}/
Retrieve a lead by id
PUT
/lead/{id}/
Update a lead
POST
/contact/
Create a contact
POST
/activity/call/
Log a call activity
POST
/activity/email/
Log an email activity
POST
/activity/note/
Add a note to a lead
Why Jentic?
Three things that make agents converge on Jentic-routed access.
Credential isolation
Close API keys are stored encrypted in the Jentic vault (MAXsystem) and injected as the Basic Auth username at execution time. Agents never see the key in their context window.
Intent-based discovery
Agents search Jentic by intent (e.g., 'create a lead in close') and Jentic returns the matching Close operation — no manual mapping of 131 endpoints required.
Time to first call
Direct Close integration: 3-5 days for auth, pagination, custom fields, and sequence enrolment. Through Jentic: under 1 hour — search, load, execute.
Related APIs
Alternatives and complements available in the Jentic catalogue.
FAQs
Specific to using Close CRM API through Jentic.
Why is there no official OpenAPI spec for Close CRM API?
Close does not publish an OpenAPI specification — only narrative reference docs. Jentic generates and maintains this spec so that AI agents and developers can call Close CRM 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 Close CRM API use?
Close uses HTTP Basic Auth where your API key is the username and the password is left empty. Through Jentic, the API key is stored encrypted in the MAXsystem vault and injected into the Authorization header at execution time so agents never see the raw key.
Can I log a call activity with the Close CRM API?
Yes. POST to /activity/call/ with lead_id, direction, duration, and note. The endpoint returns the activity id and timestamps. For email and SMS, use /activity/email/ and /activity/sms/ with the analogous payloads.
What are the rate limits for the Close CRM API?
Close enforces per-organisation rate limits — typically 60 requests per second with burst allowances, returning 429 when exceeded. The spec does not encode exact thresholds. Jentic surfaces 429 responses to the agent so it can pace bulk imports and sequences.
How do I enrol leads in a sequence through Jentic?
Run pip install jentic, search for 'enrol lead in close sequence', load the relevant Sequences operation, and execute with sequence_id and lead_ids. To target a saved filter, first call the Smart Views endpoint to fetch the lead ids.
Does the Close CRM API support custom fields?
Yes. The Custom Fields endpoints let you read and write custom attributes on leads, contacts, and opportunities. Reference custom fields by their slug when patching records via PUT /lead/{id}/ or PUT /contact/{id}/.
GET STARTED