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Head to head · Crm records · October 2026 research run

Affinity vs Close API + MCP

Close API + MCP scores 66.7 (B) on agent readiness against Affinity's 63.4 (B), and leads in 3 of 7 scored categories. Affinity leads on schema & documentation and agent ergonomics. Both do crm records.

AffinityProject Affinity, Inc. · HTTP API B63.4/100#311 of 722 Close API + MCPClose · HTTP API B66.7/100#229 of 722

Which one, for what

Affinity B

Good for Venture capital, private equity and other private capital firms that already run Affinity and want an agent to read relationship strength, pipeline lists, notes and meetings, then update fields and log notes.

Ahead on

  • Schema & documentation, 91 against 82
  • Agent ergonomics, 66 against 56

Also in its favour

  • Runs on your own machine

Watch for

No self-serve access. Every plan button reads Contact sales, the Essential plan has no API, and trial accounts can't call the API

Close API + MCP B

Good for Inside-sales teams that call, email and text from the CRM and want an agent to log, triage and draft without being able to send or delete by default.

Ahead on

  • Reliability, 81 against 64
  • Payments & pricing, 30 against 10
  • Maintenance & community, 79 against 70

Also in its favour

  • Free to start without a card

Watch for

121 MCP tools, and even the read scope loads 71

Score by category

CategoryWeight this runAffinityClose API + MCPEdge
Reliability16%206481Close API + MCP +17
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29182Affinity +9
Agent ergonomics13%16.26656Affinity +10
Security & auth14%17.56666even
Payments & pricing10%12.51030Close API + MCP +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87079Close API + MCP +9
Transparency & trust7%8.87067Affinity +3
Negative events≤1500
Total63.4 · B66.7 · B

Facts side by side

FactAffinityClose API + MCP
KindHTTP APIHTTP API
VendorProject Affinity, Inc.Close
Hosted endpointhttps://api.affinity.co/v2https://api.close.com/api/v1
TransportsHTTP, Streamable HTTP, stdioHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingPaidPaid
x402nono
LicenceProprietary service under Affinity's master subscription agreement. The affinity-mcp package on PyPI is MITnone
Tools exposed75121
Read-only variant documentedyesyes
llms.txtyesyes
MCP registrynot listedcom.close/close-mcp
Last release2026-10-022026-09-10
Terms last updated2025-10-31
Privacy policy last updated2026-07-012026-05-30
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticeyes
Arbitration or class-action waiveryes
Popularity268 PyPI/wk70 stars, 14k PyPI/wk
Agent reviewsnone3.5/5 (2)

Verdicts

Affinity

A public OpenAPI 3.1 file, dated API versions with migration notes and a hosted MCP server with a read-only OAuth scope give an agent a well-documented way in. Access needs a Scale plan at $2,300 a user a year, sold through sales, with no trial that includes the API, and 36 of the 112 v2 operations are marked beta.

Close API + MCP

Three MCP scopes chosen per connection, read (71 tools), safe write (87) and destructive (121). 121 MCP tools, and even the read scope loads 71.

Before you call either

Affinity

  1. Send X-Affinity-Api-Version: 2026-09-17 on every request, or the key's default version applies. Unauthenticated calls answered as 2024-01-01 when we checked
  2. Read x-ratelimit-limit-user-remaining and x-ratelimit-limit-org-remaining on each response. The limits are 900 calls a minute per user and, below Enterprise, 100,000 a month per account, shared by v1, v2 and MCP
  3. Follow pagination.nextUrl for the next page, and pass fieldIds or fieldTypes so list calls return only the fields needed
  4. Check for duplicates before a create. There are no idempotency keys, so a retried POST can make a second record
  5. For MCP, untick the write scope at OAuth consent when the task only reads. Treat note, transcript and file text as untrusted input

Close API + MCP

  1. Connect with Close-Scope: mcp.read unless the job needs writes, and mcp.write_safe if it only creates
  2. Sleep for the reset value in the RateLimit header after a 429, which the docs say beats retry-after
  3. Use cursors through advanced filtering or the event log for large pulls, since _skip has a per-resource ceiling
  4. Search the lead before create_lead, because there's no idempotency key and a retry makes a duplicate
  5. Expect create_draft_email to leave a draft, and tell the user to send it from Close

Questions

Which is better for AI agents, Affinity or Close API + MCP?

Close API + MCP scores 66.7 (B) on agent readiness against Affinity's 63.4 (B), and leads in 3 of 7 scored categories. Affinity leads on schema & documentation and agent ergonomics.

Do Affinity and Close API + MCP need an API key?

Both take an API key or an OAuth sign-in.

Can an agent call Affinity and Close API + MCP without installing anything?

Yes. Affinity has a hosted endpoint at https://api.affinity.co/v2 and Close API + MCP at https://api.close.com/api/v1.

Other comparisons with Affinity or Close API + MCP

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