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Head to head · Crm records · October 2026 research run

Affinity vs Nutshell

Affinity scores 63.4 (B) on agent readiness against Nutshell's 49.6 (D), and leads in 5 of 7 scored categories. Nutshell leads on payments & pricing. Both do crm records.

AffinityProject Affinity, Inc. · HTTP API B63.4/100#311 of 722 NutshellNutshell, Inc. · HTTP API D49.6/100#607 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

  • Reliability, 64 against 42
  • Schema & documentation, 91 against 57
  • Agent ergonomics, 66 against 44
  • Security & auth, 66 against 58
  • Maintenance & community, 70 against 46

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

Nutshell D

Good for Small sales teams already on Nutshell who want an agent to read pipeline data over MCP or write records over REST at a low seat price.

Ahead on

  • Payments & pricing, 35 against 10

Also in its favour

  • Free to start without a card

Watch for

No rate limit numbers, 429 handling or Retry-After found for the REST API

Score by category

CategoryWeight this runAffinityNutshellEdge
Reliability16%206442Affinity +22
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29157Affinity +34
Agent ergonomics13%16.26644Affinity +22
Security & auth14%17.56658Affinity +8
Payments & pricing10%12.51035Nutshell +25
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.87046Affinity +24
Transparency & trust7%8.87071Nutshell +1
Negative events≤1500
Total63.4 · B49.6 · D

Facts side by side

FactAffinityNutshell
KindHTTP APIHTTP API
VendorProject Affinity, Inc.Nutshell, Inc.
Hosted endpointhttps://api.affinity.co/v2https://app.nutshell.com/rest
TransportsHTTP, Streamable HTTP, stdioHTTP
AuthOAuth or keyOAuth or key
PricingPaidPaid
x402nono
LicenceProprietary service under Affinity's master subscription agreement. The affinity-mcp package on PyPI is MITProprietary service under Nutshell's Terms of Service
Tools exposed75none
Read-only variant documentedyesyes
llms.txtyesyes
Last release2026-10-022026-08-21
Terms last updated2026-06-02
Privacy policy last updated2026-07-012026-06-02
Customer content may train modelsnot found in the text
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingyes
Terms or service can change without noticeyes
Arbitration or class-action waiveryes
Popularity268 PyPI/wknone

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.

Nutshell

The REST reference is served as Markdown with an OpenAPI fragment per operation, and the hosted MCP server uses OAuth with PKCE and can only read. No rate limit numbers, error format or API changelog were found in the reviewed documentation, and API keys carry no scopes.

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

Nutshell

  1. Authenticate REST calls with HTTP Basic, a Nutshell user's email as username and the API key as password, against https://app.nutshell.com/rest
  2. Use IDs in the <number>-<type> form, such as 3-accounts, and send updates as JSON Patch with content-type: application/json-patch+json
  3. Page lists with page[limit] and page[page], which is 0-based, and call /accounts/list/fields or the lead and contact equivalents for valid filter keys
  4. Use the REST API for writes. The MCP server only reads, and OAuth tokens need the read scope
  5. Filter webhook events yourself, because every webhook receives all events and subscriptions are created in Setup, not through the API

Questions

Which is better for AI agents, Affinity or Nutshell?

Affinity scores 63.4 (B) on agent readiness against Nutshell's 49.6 (D), and leads in 5 of 7 scored categories. Nutshell leads on payments & pricing.

Do Affinity and Nutshell need an API key?

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

Can an agent call Affinity and Nutshell without installing anything?

Yes. Affinity has a hosted endpoint at https://api.affinity.co/v2 and Nutshell at https://app.nutshell.com/rest.

Other comparisons with Affinity or Nutshell

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