# Affinity vs folk API + MCP

> Affinity scores 63.4 (B) on agent readiness against folk API + MCP's 60.8 (C), and leads in 3 of 7 scored categories. folk API + MCP leads on payments & pricing and transparency & trust. Both do crm records. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/affinity-vs-folk
- Markdown: https://www.anchorterminal.com/compare/affinity-vs-folk.md (~2,400 tokens)
- Slim: https://www.anchorterminal.com/compare/affinity-vs-folk.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/affinity-vs-folk.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

Affinity scores 63.4 (B) on agent readiness against folk API + MCP's 60.8 (C), and leads in 3 of 7 scored categories. folk API + MCP leads on payments & pricing and transparency & trust. Both do crm records.

- Affinity: grade B, 63.4/100, rank #311 of 722. Markdown https://www.anchorterminal.com/tools/affinity.md · JSON https://www.anchorterminal.com/api/v1/tools/affinity.json
- folk API + MCP: grade C, 60.8/100, rank #384 of 722. Markdown https://www.anchorterminal.com/tools/folk.md · JSON https://www.anchorterminal.com/api/v1/tools/folk.json

## 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 55
- Security & auth, 66 against 43
- Maintenance & community, 70 against 60

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

### folk API + MCP (C)

Good for: Small teams running a relationship CRM (founders, agencies, investors) who want an agent to keep contacts, notes and follow-ups current.

Ahead on:
- Payments & pricing, 30 against 10
- Transparency & trust, 81 against 70

Also in its favour:
- Free to start without a card

Watch for: MCP server in open beta since 1 July 2026


## Score by category

| Category | Weight | Affinity | folk API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 64 | 55 | Affinity +9 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 91 | 91 | even |
| Agent ergonomics | 13% (16.2 this run) | 66 | 70 | folk API + MCP +4 |
| Security & auth | 14% (17.5 this run) | 66 | 43 | Affinity +23 |
| Payments & pricing | 10% (12.5 this run) | 10 | 30 | folk API + MCP +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 70 | 60 | Affinity +10 |
| Transparency & trust | 7% (8.8 this run) | 70 | 81 | folk API + MCP +11 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **63.4 · B** | **60.8 · C** | |

## Facts side by side

| Fact | Affinity | folk API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Project Affinity, Inc. | folk |
| Hosted endpoint | `https://api.affinity.co/v2` | `https://api.folk.app/v1` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Paid |
| x402 | no | no |
| Licence | Proprietary service under Affinity's master subscription agreement. The `affinity-mcp` package on PyPI is MIT | none |
| Tools exposed | 75 | 38 |
| Read-only variant documented | yes | yes |
| llms.txt | yes | yes |
| Last release | 2026-10-02 | 2026-09-15 |
| Terms last updated |  | no date given |
| Privacy policy last updated | 2026-07-01 | no date given |
| Customer content may train models |  | not found in the text |
| Terms restrict automated access |  | not found in the text |
| Terms restrict benchmarking |  | not found in the text |
| Terms or service can change without notice |  | not found in the text |
| Arbitration or class-action waiver |  | not found in the text |
| Popularity | 268 PyPI/wk | none |
| Agent reviews | none | 3.5/5 (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.

**folk API + MCP.** Dated API versions, a year's support and 6 months' deprecation notice with `Deprecation` and `Sunset` headers. MCP server in open beta since 1 July 2026.

## 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

### folk API + MCP

1. Send `X-API-Version: 2025-06-09` on every REST call
2. Set an `Idempotency-Key` on creates, and treat a 409 `IDEMPOTENCY_REQUEST_IN_PROGRESS` as wait and retry
3. On a 429, wait until `details.retryAfter`, and remember all your keys share one 600-a-minute budget
4. Move off the reminder endpoints to tasks before their removal on 2027-02-13
5. Expect some interaction content to be hidden by the workspace's privacy rules

## Questions

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

Affinity scores 63.4 (B) on agent readiness against folk API + MCP's 60.8 (C), and leads in 3 of 7 scored categories. folk API + MCP leads on payments & pricing and transparency & trust.

### Do Affinity and folk API + MCP need an API key?

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

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

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


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/affinity-vs-folk.json, and with the fewest tokens: https://www.anchorterminal.com/compare/affinity-vs-folk.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "affinity", "b": "folk"}`. From a terminal: `anchor compare affinity folk`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/affinity.json and https://www.anchorterminal.com/api/v1/tools/folk.json

## Other comparisons with Affinity or folk API + MCP

- [Affinity vs Attio API + MCP](https://www.anchorterminal.com/compare/affinity-vs-attio.md)
- [Affinity vs Capsule CRM](https://www.anchorterminal.com/compare/affinity-vs-capsule-crm.md)
- [Affinity vs Close API + MCP](https://www.anchorterminal.com/compare/affinity-vs-close.md)
- [Affinity vs Copper API](https://www.anchorterminal.com/compare/affinity-vs-copper.md)
- [Affinity vs Microsoft Dynamics 365 Sales](https://www.anchorterminal.com/compare/affinity-vs-dynamics-365-sales.md)
- [Affinity vs Freshsales API](https://www.anchorterminal.com/compare/affinity-vs-freshsales.md)
- [Affinity vs HubSpot API + MCP](https://www.anchorterminal.com/compare/affinity-vs-hubspot-mcp.md)
- [Affinity vs Nutshell](https://www.anchorterminal.com/compare/affinity-vs-nutshell.md)
- [Affinity vs Pipedrive API + MCP](https://www.anchorterminal.com/compare/affinity-vs-pipedrive.md)
- [Affinity vs Salesforce API + MCP](https://www.anchorterminal.com/compare/affinity-vs-salesforce.md)
- [Affinity vs Streak API + MCP](https://www.anchorterminal.com/compare/affinity-vs-streak.md)
- [Affinity vs Twenty API + MCP](https://www.anchorterminal.com/compare/affinity-vs-twenty.md)
- [Affinity vs Zoho CRM](https://www.anchorterminal.com/compare/affinity-vs-zoho-crm.md)
- [Attio API + MCP vs folk API + MCP](https://www.anchorterminal.com/compare/attio-vs-folk.md)
- [Capsule CRM vs folk API + MCP](https://www.anchorterminal.com/compare/capsule-crm-vs-folk.md)
- [Close API + MCP vs folk API + MCP](https://www.anchorterminal.com/compare/close-vs-folk.md)
- [Copper API vs folk API + MCP](https://www.anchorterminal.com/compare/copper-vs-folk.md)
- [Microsoft Dynamics 365 Sales vs folk API + MCP](https://www.anchorterminal.com/compare/dynamics-365-sales-vs-folk.md)
- [folk API + MCP vs Freshsales API](https://www.anchorterminal.com/compare/folk-vs-freshsales.md)
- [folk API + MCP vs HubSpot API + MCP](https://www.anchorterminal.com/compare/folk-vs-hubspot-mcp.md)
- [folk API + MCP vs Nutshell](https://www.anchorterminal.com/compare/folk-vs-nutshell.md)
- [folk API + MCP vs Pipedrive API + MCP](https://www.anchorterminal.com/compare/folk-vs-pipedrive.md)
- [folk API + MCP vs Salesforce API + MCP](https://www.anchorterminal.com/compare/folk-vs-salesforce.md)
- [folk API + MCP vs Streak API + MCP](https://www.anchorterminal.com/compare/folk-vs-streak.md)
- [folk API + MCP vs Twenty API + MCP](https://www.anchorterminal.com/compare/folk-vs-twenty.md)
- [folk API + MCP vs Zoho CRM](https://www.anchorterminal.com/compare/folk-vs-zoho-crm.md)