Close CRM API
Sales-focused CRM API with built-in calling, emailing, SMS, and activity tracking designed for high-velocity inside sales teams.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Basic auth with API key is functional but lacks scope granularity — a leaked key grants full account access. No OAuth or token rotation support. HTTPS enforced.
⚡ Reliability
Best When
An agent supports inside sales workflows where call logging, email tracking, and lead activity history are central to the use case.
Avoid When
You need a full marketing automation suite or deep enterprise CRM customization beyond sales pipeline management.
Use Cases
- • Logging call outcomes and recording notes after agent-assisted sales calls
- • Creating and updating leads with custom fields from inbound prospect data
- • Querying lead activity history to determine follow-up timing and priority
- • Sending templated emails through Close's built-in email sequences via API
- • Tracking pipeline stage transitions to trigger downstream agent workflows
Not For
- • Marketing automation or campaign management (Close focuses on sales execution, not marketing)
- • Large enterprise orgs needing complex multi-object hierarchies like Salesforce
- • Teams not doing inside sales who don't need built-in calling or email tracking
Interface
Authentication
Single API key per user passed via HTTP Basic auth (key as username, empty password). Simple but means per-user keys for multi-user agents. No OAuth or fine-grained scopes.
Pricing
No free tier after trial. API access included on all paid plans. Pricing is per-seat which can be costly for larger teams.
Agent Metadata
Known Gotchas
- ⚠ API key is tied to a specific user account — all actions appear as that user in the audit log, which can cause attribution confusion
- ⚠ Lead vs Contact vs Opportunity model differs from Salesforce; 'Lead' in Close contains both company and contact info in one object
- ⚠ Custom fields require knowing the custom field ID (not name) in API calls; IDs must be fetched separately from a meta endpoint
- ⚠ Bulk endpoints (export) are asynchronous and return job IDs; agents must poll for completion rather than getting data immediately
- ⚠ Rate limit of 60 req/min applies globally across all API keys for an account, not per key — parallel agent calls can exhaust limits quickly
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Close CRM API.
Scores are editorial opinions as of 2026-03-06.