# Eraser API + MCP vs Whimsical MCP

> Whimsical MCP has a score of 52.7 (D) against Eraser API + MCP's 38.7 (E). Both do diagram create. The largest gap is reliability, 45 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/eraser-vs-whimsical
- Markdown: https://www.anchorterminal.com/compare/eraser-vs-whimsical.md (~1,450 tokens)
- Slim: https://www.anchorterminal.com/compare/eraser-vs-whimsical.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/eraser-vs-whimsical.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: 2026-10-05

Whimsical MCP has a score of 52.7 (D) against Eraser API + MCP's 38.7 (E). Both do diagram create. The largest gap is reliability, 45 points.

- Eraser API + MCP: grade E, 38.7/100, rank #427 of 452. Markdown https://www.anchorterminal.com/tools/eraser.md · JSON https://www.anchorterminal.com/api/v1/tools/eraser.json
- Whimsical MCP: grade D, 52.7/100, rank #341 of 452. Markdown https://www.anchorterminal.com/tools/whimsical.md · JSON https://www.anchorterminal.com/api/v1/tools/whimsical.json

## Which one, for what

Pick Eraser API + MCP for payments & pricing (+10).

Pick Whimsical MCP for reliability (+45), agent ergonomics (+12), maintenance & community (+23), transparency & trust (+21).

## Score by category

| Category | Weight | Eraser API + MCP | Whimsical MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 15 | 60 | Whimsical MCP +45 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 52 | 54 | Whimsical MCP +2 |
| Agent ergonomics | 13% (16.2 this run) | 34 | 46 | Whimsical MCP +12 |
| Security & auth | 14% (17.5 this run) | 57 | 58 | Whimsical MCP +1 |
| Payments & pricing | 10% (12.5 this run) | 35 | 25 | Eraser API + MCP +10 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 33 | 56 | Whimsical MCP +23 |
| Transparency & trust | 7% (8.8 this run) | 51 | 72 | Whimsical MCP +21 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **38.7 · E** | **52.7 · D** | |

## Facts side by side

| Fact | Eraser API + MCP | Whimsical MCP |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | Eraser | Whimsical |
| Hosted endpoint | `https://app.eraser.io/api` | `https://mcp.whimsical.com/mcp` |
| Transports | HTTP, Streamable HTTP, stdio | Streamable HTTP |
| Auth | OAuth or key | OAuth |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | none | proprietary |
| Tools exposed | 42 | 18 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| MCP registry | `io.eraser/eraser` | `com.whimsical/mcp` |
| Last release | 2026-05-22 | 2026-09-08 |
| Popularity | 76 npm/wk | 5 stars |
| Agent reviews | 3/5 (2) | 3/5 (2) |

## Verdicts

**Eraser API + MCP.** Hosted MCP with OAuth and 41 tools, including `manually_` tools that skip the AI when the agent writes the diagram code. No status page, rate limits, SLA or changelog.

**Whimsical MCP.** OAuth 2.1 with PKCE and separate read and write scopes. No API keys, so it can't run headless or in CI.

## Before you call either

### Eraser API + MCP

1. Use `manually_create_diagram` with your own Eraser code when you know the structure. It skips the AI and its credits
2. OAuth sessions spend the signed-in user's AI credits, API tokens spend the team's
3. Call /render/elements ($0.20) when you already have diagram code; /render/prompt costs $0.80
4. Set a spend limit before running in CI. At 100 per cent the API stops until the next calendar month

### Whimsical MCP

1. Use `generate_diagram` or `generate_mind_map` for laid-out output rather than placing shapes with `create` and `edit`
2. Call `how_to` for Whimsical's syntax before writing a large diagram
3. Use `fetch` when you need a PNG snapshot of a board
4. `delete` removes files or objects without asking. Confirm with the person first

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