# ActiveCampaign vs Mailchimp Marketing API

> Mailchimp Marketing API scores 57.4 (C) on agent readiness against ActiveCampaign's 50.5 (D), and leads in 5 of 7 scored categories. ActiveCampaign leads on reliability and payments & pricing. Both do marketing profiles. Category scores, facts, verdicts and agent notes side by…

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- Markdown: https://www.anchorterminal.com/compare/activecampaign-vs-mailchimp-marketing.md (~2,250 tokens)
- Slim: https://www.anchorterminal.com/compare/activecampaign-vs-mailchimp-marketing.min.md (~730 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/activecampaign-vs-mailchimp-marketing.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

Mailchimp Marketing API scores 57.4 (C) on agent readiness against ActiveCampaign's 50.5 (D), and leads in 5 of 7 scored categories. ActiveCampaign leads on reliability and payments & pricing. Both do marketing profiles.

- ActiveCampaign: grade D, 50.5/100, rank #684 of 842. Markdown https://www.anchorterminal.com/tools/activecampaign.md · JSON https://www.anchorterminal.com/api/v1/tools/activecampaign.json
- Mailchimp Marketing API: grade C, 57.4/100, rank #549 of 842. Markdown https://www.anchorterminal.com/tools/mailchimp-marketing.md · JSON https://www.anchorterminal.com/api/v1/tools/mailchimp-marketing.json

## Which one, for what

### ActiveCampaign (D)

Good for: Small and mid-sized teams already on ActiveCampaign that want an agent to maintain contacts, segments and campaign drafts and enrol contacts in automations.

Ahead on:
- Reliability, 67 against 60
- Payments & pricing, 30 against 25

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

Watch for: Three critical incidents on status.activecampaign.com between 27 July and 28 September 2026, one of about 24 hours 41 minutes on EU segmented campaigns

### Mailchimp Marketing API (C)

Good for: Small businesses already on Mailchimp that want an agent to sync contacts, tag and segment them, record events, draft and schedule campaigns and read reports.

Ahead on:
- Schema & documentation, 76 against 68
- Agent ergonomics, 73 against 52
- Security & auth, 46 against 33
- Maintenance & community, 63 against 35
- Transparency & trust, 74 against 57

Also in its favour:
- A hosted endpoint, with nothing to install

Watch for: An API key has full account access. The docs say there is no read-only key and no way to limit a key to chosen endpoints


## Score by category

| Category | Weight | ActiveCampaign | Mailchimp Marketing API | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 67 | 60 | ActiveCampaign +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 68 | 76 | Mailchimp Marketing API +8 |
| Agent ergonomics | 13% (16.2 this run) | 52 | 73 | Mailchimp Marketing API +21 |
| Security & auth | 14% (17.5 this run) | 33 | 46 | Mailchimp Marketing API +13 |
| Payments & pricing | 10% (12.5 this run) | 30 | 25 | ActiveCampaign +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 35 | 63 | Mailchimp Marketing API +28 |
| Transparency & trust | 7% (8.8 this run) | 57 | 74 | Mailchimp Marketing API +17 |
| Negative events | ≤15 | 0 | -2 | |
| **Total** | | **50.5 · D** | **57.4 · C** | |

## Facts side by side

| Fact | ActiveCampaign | Mailchimp Marketing API |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | ActiveCampaign, LLC | Intuit Mailchimp |
| Hosted endpoint | no (local only) | `https://api.mailchimp.com/3.0` |
| Transports | HTTP, Streamable HTTP | HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Freemium |
| x402 | no | no |
| Licence | Proprietary service under ActiveCampaign's terms of service and API licence agreement | Proprietary service under Mailchimp's Standard Terms of Use and API Use Policy. The generated client libraries declare Apache-2.0 in their package metadata |
| Tools exposed | 50 | none |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| Last release | 2026-09-02 | 2026-10-05 |
| Terms last updated | 2025-12-23 | no date given |
| Privacy policy last updated | 2026-10-01 | 2026-03-09 |
| Customer content may train models | yes | yes |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | not found in the text | not found in the text |
| Terms or service can change without notice | yes | yes |
| Arbitration or class-action waiver | yes | yes |
| Popularity | none | 278k npm/wk, 111k PyPI/wk |

## Verdicts

**ActiveCampaign.** The v3 REST API covers contacts, segments, campaign scheduling and bulk import, with OpenAPI 3.1 definitions inside public Markdown reference pages and documented Retry-After on 429s. Each user has one unscoped API key, the limit is 5 requests a second, and no changelog was found. The status page shows three critical incidents between 27 July and 28 September 2026.

**Mailchimp Marketing API.** A public OpenAPI 3.1 file covers all 297 operations, every docs page has a Markdown copy, and responses can be trimmed with `fields`. An API key carries full account access with no read-only option. The quick start's TypeScript package was not on npm on 8 October 2026, and the changelog's newest entry is 19 August 2025.

## Before you call either

### ActiveCampaign

1. Take the base URL from Settings, Developer in the account. Do not build it from the account name, because non-US accounts may not sit on api-us1.com
2. Use POST /contact/sync to upsert by email, and POST /import/bulk_import for up to 250 contacts, then read each row's outcome from GET /import/info
3. Page large contact sets with `orders[id]=ASC` and `id_greater`, not `offset`. Unsupported filter and order keys are silently ignored
4. Check `succeeded` in the body after scheduling, pausing or stopping a campaign. Business-rule failures return 200 with `succeeded` set to 0
5. Stay under 5 requests a second per account and wait for the Retry-After value on a 429

### Mailchimp Marketing API

1. Send the key or OAuth token as `Authorization: Bearer` to `https://api.mailchimp.com/3.0/`. Treat it as full account access and keep it server-side
2. Address a contact by the MD5 hash of the lowercase email address, and use PUT on `/lists/{list_id}/members/{subscriber_hash}` so a retry does not create a duplicate
3. Ask a person before POST `/campaigns/{campaign_id}/actions/send`. Read `/campaigns/{campaign_id}/send-checklist` and use `actions/test` first
4. Keep to 10 concurrent requests per user, and send large jobs to `/batches`. A 429 names no wait time, so back off and retry
5. Add `fields=` to every list call and set `count` (default 10, maximum 1,000) with `offset`
6. Set `is_syncing` to true when loading historical events so they do not trigger automations

## Questions

### Which is better for AI agents, ActiveCampaign or Mailchimp Marketing API?

Mailchimp Marketing API scores 57.4 (C) on agent readiness against ActiveCampaign's 50.5 (D), and leads in 5 of 7 scored categories. ActiveCampaign leads on reliability and payments & pricing.

### Do ActiveCampaign and Mailchimp Marketing API need an API key?

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

### Can an agent call ActiveCampaign and Mailchimp Marketing API without installing anything?

No hosted endpoint is listed for ActiveCampaign. Mailchimp Marketing API has a hosted endpoint at https://api.mailchimp.com/3.0.


## For agents

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

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