Close CRM API
Close CRM REST API — programmatic access to leads, contacts, opportunities, activities, calls, and email sequences in the sales-optimized CRM built for inside sales teams with built-in calling and email sequence automation.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
SOC2 Type II. GDPR compliant. Basic auth with API key — simple but not scope-granular. Key has full account access tied to user permissions. US data processing. Audit logs available.
⚡ Reliability
Best When
You need to automate inside sales workflows for a team that relies heavily on calls and email sequences with a developer-friendly API.
Avoid When
You need enterprise-grade customization or non-sales use cases — Close's strength is specifically inside sales automation.
Use Cases
- • Agents enriching Close CRM leads with company research and adding notes before sales rep follow-up
- • Activity automation — agents logging AI-generated call summaries and meeting notes to lead timelines in Close
- • Lead scoring — agents querying Close lead data, analyzing activity patterns, and updating custom fields with scores
- • Sequence enrollment — agents automatically enrolling leads in email sequences based on triggering behaviors
- • Pipeline reporting — agents querying Close opportunity data for custom sales reporting dashboards and forecasts
Not For
- • Enterprise CRM needs — Close is optimized for SMB inside sales; use Salesforce for enterprise complexity
- • Non-sales use cases — Close is purpose-built for sales; use HubSpot for marketing + CRM combined workflows
- • Field sales teams — Close is optimized for inside sales (phone, email); use a mobile-first CRM for field reps
Interface
Authentication
API key via HTTP Basic auth (key as username, empty password). Key scoped to the account with the key owner's permissions. Keys are created per user in account settings. No OAuth for third-party integrations.
Pricing
14-day free trial. API access on all plans. Calling minutes included in Professional and Enterprise. Annual billing saves ~20%.
Agent Metadata
Known Gotchas
- ⚠ Lead and Contact are separate entities in Close — agents must understand the Lead > Contact hierarchy
- ⚠ Custom activities require custom activity type setup before API use — can't create arbitrary activity types on the fly
- ⚠ Email sequences (Smart Views enrollment) require specific plan tier — not available on Startup plan
- ⚠ Bulk import endpoints are async — agents must poll for import job completion
- ⚠ Phone number formatting must include country code — E.164 format required for calling features to work
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.