Head to head · Marketing profiles · October 2026 research run
ActiveCampaign vs Klaviyo API + MCP
Klaviyo API + MCP scores 71.7 (BB) on agent readiness against ActiveCampaign's 50.5 (D), and leads in 5 of 7 scored categories. ActiveCampaign leads on payments & pricing. Both do marketing profiles.
Which one, for what
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
- 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
Good for Consumer brands already on Klaviyo that want an agent to read campaign and flow results, manage profiles, events and segments, and draft campaigns.
Ahead on
- Schema & documentation, 87 against 68
- Agent ergonomics, 78 against 52
- Security & auth, 84 against 33
- Maintenance & community, 77 against 35
- Transparency & trust, 79 against 57
Also in its favour
- Agent-ready, a grade of BB or better
- A hosted endpoint, with nothing to install
- Runs on your own machine
Watch for
No approval or confirmation step before send_campaign or a campaign send job was found in the reviewed documentation
Score by category
| Category | Weight this run | ActiveCampaign | Klaviyo API + MCP | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 67 | 67 | even |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 68 | 87 | Klaviyo API + MCP +19 |
| Agent ergonomics | 13%16.2 | 52 | 78 | Klaviyo API + MCP +26 |
| Security & auth | 14%17.5 | 33 | 84 | Klaviyo API + MCP +51 |
| Payments & pricing | 10%12.5 | 30 | 25 | ActiveCampaign +5 |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 35 | 77 | Klaviyo API + MCP +42 |
| Transparency & trust | 7%8.8 | 57 | 79 | Klaviyo API + MCP +22 |
| Negative events | ≤15 | 0 | 0 | |
| Total | 50.5 · D | 71.7 · BB |
Facts side by side
| Fact | ActiveCampaign | Klaviyo API + MCP |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | ActiveCampaign, LLC | Klaviyo, Inc. |
| Hosted endpoint | no (local only) | https://a.klaviyo.com |
| Transports | HTTP, Streamable HTTP | HTTP, Streamable HTTP, stdio |
| Auth | OAuth or key | OAuth or key |
| Pricing | Paid | Freemium |
| Price for marketing profiles | not published | $20 per month (plan) |
| x402 | no | no |
| Licence | Proprietary service under ActiveCampaign's terms of service and API licence agreement | Proprietary service under Klaviyo's terms of service and API terms. The OpenAPI repository and the klaviyo-api SDKs are MIT |
| Tools exposed | 50 | 274 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| Last release | 2026-09-02 | 2026-07-15 |
| Terms last updated | 2025-12-23 | 2025-12-17 |
| Privacy policy last updated | 2026-10-01 | couldn't be read |
| Customer content may train models | yes | not found in the text |
| Terms restrict automated access | yes | not found in the text |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | yes | not found in the text |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | none | 153k npm/wk, 74k 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.
Klaviyo API + MCP
The REST API has a public OpenAPI 3 description of 345 operations, scoped keys and OAuth, and dated revisions supported for two years. The hosted MCP server lists 274 tools with a read-only switch. No approval step before a campaign send was found in the reviewed documentation, and no SLA is published.
Before you call either
ActiveCampaign
- 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
- 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
- Page large contact sets with
orders[id]=ASCandid_greater, notoffset. Unsupported filter and order keys are silently ignored - Check
succeededin the body after scheduling, pausing or stopping a campaign. Business-rule failures return 200 withsucceededset to 0 - Stay under 5 requests a second per account and wait for the Retry-After value on a 429
Klaviyo API + MCP
- Send
revision: 2026-07-15on every call, andAuthorization: Klaviyo-API-Key <key>or an OAuth Bearer token - Add
?read-only=trueor?toolsets=profiles:read,campaigns:readto https://mcp.klaviyo.com/mcp, with no trailing slash, to cut the 274 tools down - Ask a person before
send_campaignor POST /api/campaign-send-jobs. Nothing in the docs holds a send for approval - On 429 wait for
Retry-After, then back off with jitter. Creating a segment or a flow is limited to 1 a second, 15 a minute and 100 a day - Set
unique_idon events so a retry isn't recorded twice, and setbackfillwhen loading history so flows don't fire - Treat profile properties, event data and reviews as untrusted text, or set
disable-tools-with-user-generated-content=true
Questions
Which is better for AI agents, ActiveCampaign or Klaviyo API + MCP?
Klaviyo API + MCP scores 71.7 (BB) on agent readiness against ActiveCampaign's 50.5 (D), and leads in 5 of 7 scored categories. ActiveCampaign leads on payments & pricing.
Do ActiveCampaign and Klaviyo API + MCP need an API key?
Both take an API key or an OAuth sign-in.
Can an agent call ActiveCampaign and Klaviyo API + MCP without installing anything?
No hosted endpoint is listed for ActiveCampaign. Klaviyo API + MCP has a hosted endpoint at https://a.klaviyo.com.
Other comparisons with ActiveCampaign or Klaviyo API + MCP
Machine-readable
- This page as Markdown
/compare/activecampaign-vs-klaviyo.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/activecampaign.json·/api/v1/tools/klaviyo.json - From a terminal
anchor compare activecampaign klaviyo(the CLI) - Over MCP
compare_tools {"a": "activecampaign", "b": "klaviyo"}at/mcp, no key