# ButterCMS vs Sanity

> Sanity scores 73.7 (BB) to ButterCMS's 53.3 (D) for content management. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/buttercms-vs-sanity
- Markdown: https://www.anchorterminal.com/compare/buttercms-vs-sanity.md (~2,500 tokens)
- Slim: https://www.anchorterminal.com/compare/buttercms-vs-sanity.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/buttercms-vs-sanity.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

Sanity scores 73.7 (BB) on agent readiness against ButterCMS's 53.3 (D), and leads in 6 of 7 scored categories. ButterCMS leads on reliability. Both do content management.

- ButterCMS: grade D, 53.3/100, rank #711 of 950. Markdown https://www.anchorterminal.com/tools/buttercms.md · JSON https://www.anchorterminal.com/api/v1/tools/buttercms.json
- Sanity: grade BB, 73.7/100, rank #84 of 950. Markdown https://www.anchorterminal.com/tools/sanity.md · JSON https://www.anchorterminal.com/api/v1/tools/sanity.json
- Best headless CMS and website publishing for AI agents: https://www.anchorterminal.com/best/cms/index.md
- All 91 cms comparisons: https://www.anchorterminal.com/compare/cms/index.md

## Which one, for what

### ButterCMS (D)

Good for: A team already on a paid ButterCMS plan that wants an agent to draft and publish pages, collection items and blog posts in small volumes.

Ahead on:
- Reliability, 83 against 77

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

Watch for: The Write API is a paid add-on on Advanced ($249 a month) and Professional ($399), capped at 2,000 and 5,000 write calls a month. Its price is not published

### Sanity (BB)

Good for: Teams that model content as structured documents and want an agent to draft, patch and stage changes in releases for a person to publish.

Ahead on:
- Schema & documentation, 87 against 78
- Agent ergonomics, 74 against 64
- Security & auth, 67 against 36
- Payments & pricing, 40 against 20
- Maintenance & community, 89 against 27
- Transparency & trust, 87 against 51

Also in its favour:
- Agent-ready, a grade of BB or better

Watch for: Schema validation rules run only in Sanity Studio. The HTTP mutation API accepts a document without checking them


## Score by category

| Category | Weight | ButterCMS | Sanity | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 83 | 77 | ButterCMS +6 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 87 | Sanity +9 |
| Agent ergonomics | 13% (16.2 this run) | 64 | 74 | Sanity +10 |
| Security & auth | 14% (17.5 this run) | 36 | 67 | Sanity +31 |
| Payments & pricing | 10% (12.5 this run) | 20 | 40 | Sanity +20 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 27 | 89 | Sanity +62 |
| Transparency & trust | 7% (8.8 this run) | 51 | 87 | Sanity +36 |
| Negative events | ≤15 | -2 | 0 | |
| **Total** | | **53.3 · D** | **73.7 · BB** | |

## Facts side by side

| Fact | ButterCMS | Sanity |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | ButterCMS LLC | Sanity US Inc. and Sanity AS |
| Hosted endpoint | `https://api.buttercms.com/v2` | `https://api.sanity.io` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under ButterCMS's terms of service. The SDKs and starter projects on GitHub are MIT | Proprietary hosted service under Sanity's terms of service. Sanity Studio, the CLI, `@sanity/client` and the agent toolkit on GitHub are MIT |
| Tools exposed | none | 53 |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | not listed | `io.sanity.www/mcp` |
| Last release | 2025-09-04 | 2026-10-02 |
| Terms last updated | no date given | no date given |
| Privacy policy last updated | 2022-08-15 | no date given |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 6.9k npm/wk | 6.4k stars, 4.1M npm/wk |

## Verdicts

**ButterCMS.** The Read and Write APIs have a public OpenAPI 3.1 file, Markdown docs and a status page with no incident since October 2025. The Write API is a paid add-on from the $249 plan, capped at 2,000 or 5,000 calls a month. Writes answer 202 with no identifier, support rotates tokens, and the terms are an undated website document.

**Sanity.** Sanity publishes 26 OpenAPI specs covering 225 operations, and its hosted MCP server saves edits to drafts or release versions, with publishing as a separate call. The Content Lake does not run schema validation on API writes, and custom roles that limit a token to one dataset or document type are sold only on Enterprise plans.

## Before you call either

### ButterCMS

1. End every path with a slash. A missing slash returns a 301, and the vendor counts the redirect and the retry as two API calls
2. Send the write token only as `Authorization: Token <token>`. The `auth_token` query parameter works for reads only
3. On page creation send every field key of the page type, with empty strings for fields left blank
4. A 202 means queued, not saved. Read the entry back with `preview=1` to confirm, and check a slug exists before retrying a create
5. Call the REST API directly for writes. The JavaScript SDK 3.0.3 has list, retrieve and search methods only

### Sanity

1. Pin a static dated version in every URL, such as `v2025-02-19`. Omitting `apiVersion` in `@sanity/client` falls back to `v1`.
2. Validate documents against the schema yourself before an HTTP write, or run `sanity documents validate` afterwards. The Content Lake does not enforce schema rules.
3. Back off on 429 for mutations yourself. `@sanity/client` retries queries five times but never retries mutations. The limit is 25 mutations a second per IP.
4. Over MCP, call `create_version` before `patch_documents` when editing inside a release, then patch the returned version ID with the same `releaseId`.
5. Use GROQ projections and slices to size results. MCP query responses are limited to 64 KiB, and a blocked Free project answers 402 with `plan_limit_reached`.

## Questions

### Which is better for AI agents, ButterCMS or Sanity?

Sanity scores 73.7 (BB) on agent readiness against ButterCMS's 53.3 (D), and leads in 6 of 7 scored categories. ButterCMS leads on reliability.

### Do ButterCMS and Sanity need an API key?

ButterCMS needs an API key. Sanity takes an API key or an OAuth sign-in.

### Can an agent call ButterCMS and Sanity without installing anything?

Yes. ButterCMS has a hosted endpoint at https://api.buttercms.com/v2 and Sanity at https://api.sanity.io.


## For agents

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

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- [Sanity vs WordPress](https://www.anchorterminal.com/compare/sanity-vs-wordpress.md)