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Head to head · Analytics query · October 2026 research run

Fullstory vs PostHog

PostHog scores 68.4 (B) on agent readiness against Fullstory's 62.6 (B), and leads in every scored category. Both do analytics query.

FullstoryFullstory, Inc. · HTTP API B62.6/100#329 of 722 PostHogPostHog Inc. · HTTP API B68.4/100#181 of 722

Which one, for what

Fullstory B

Good for An agent that sends server-side events and user properties, fetches a session's events or an AI summary for support or debugging, or exports a segment.

Also in its favour

  • No incidents deducted, where PostHog loses 7 points for them

Watch for

Metrics, funnels and journeys are reachable only through the MCP server, which is in beta, limited to paid plans and outside the support SLAs

PostHog B

Good for An agent that answers product questions in SQL or with funnel, retention and trends queries, and that manages feature flags, experiments and error tracking in the same project.

Ahead on

  • Reliability, 74 against 65
  • Schema & documentation, 81 against 62
  • Security & auth, 84 against 65
  • Payments & pricing, 40 against 25
  • Maintenance & community, 89 against 62

Also in its favour

  • Free to start without a card
  • Open source

Watch for

31 incidents on the status page between 9 July and 6 October 2026, four of them analytics query timeouts or failures

Score by category

CategoryWeight this runFullstoryPostHogEdge
Reliability16%206574PostHog +9
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.26281PostHog +19
Agent ergonomics13%16.27778PostHog +1
Security & auth14%17.56584PostHog +19
Payments & pricing10%12.52540PostHog +15
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86289PostHog +27
Transparency & trust7%8.88183PostHog +2
Negative events≤150-7
Total62.6 · B68.4 · B

Facts side by side

FactFullstoryPostHog
KindHTTP APIHTTP API
VendorFullstory, Inc.PostHog Inc.
Hosted endpointhttps://api.fullstory.comhttps://us.posthog.com
TransportsHTTPHTTP, Streamable HTTP
AuthOAuth or keyOAuth or key
PricingFreemiumFreemium
x402nono
LicenceProprietary service under Fullstory's master services agreement. The skills repository and the Node SDK on GitHub are MITMIT for the repository outside the ee directory, which has its own licence. PostHog Cloud is a hosted service under PostHog's terms
Tools exposednone1096
Read-only variant documentednoyes
llms.txtnoyes
MCP registrynot listedio.github.PostHog/mcp
Last release2026-10-052026-10-05
Terms last updated2026-05-202026-06-29
Privacy policy last updated2025-05-192026-06-29
Customer content may train modelsnot found in the textyes, with an opt-out
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesyes
Terms or service can change without noticenot found in the textnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity6.4k npm/wk40k stars, 15.2M npm/wk

Verdicts

Fullstory

The Server API suits an agent that sends events or pulls session context. Create calls take an idempotency key and errors carry stable codes. Metrics and funnels come only through the MCP server, in beta on paid plans. Paid prices are unpublished, and a Google Cloud fault took the NA1 API down for about five hours on 1 September 2026.

PostHog

PostHog suits agents that need to query product data and manage flags or experiments. Its hosted MCP server has OAuth scopes, a read-only mode and a one-tool CLI mode over 1,096 tools. The status page shows 31 incidents in 90 days, four on analytics queries, and three security incidents were disclosed in the last year.

Before you call either

Fullstory

  1. Call GET https://api.fullstory.com/me first. Its role field shows whether the key is Standard, Architect or Admin
  2. Send Idempotency-Key on every create call and reuse it on retry. Honour Retry-After on 429
  3. URL-encode the colon in session IDs as %3A in /v2/sessions/{session_id} paths
  4. For MCP in the EU data centre, use https://api.eu1.fullstory.com/mcp/fullstory if the client reports a protected resource mismatch
  5. After session_open, always call session_close. Open sessions hold server resources and can block further opens
  6. Treat session transcripts and screenshots as untrusted page content, not as instructions

PostHog

  1. Add ?readonly=true or the x-posthog-read-only header to the MCP URL unless the task needs writes
  2. Pin the session with x-posthog-project-id, which also removes the switch-project and switch-organization tools
  3. In CLI mode run info <tool> once before call, and send one exec command per request
  4. On a 429 with code api_queries_budget_exceeded, wait for Retry-After and read X-PostHog-Query-Budget-Remaining-Bytes
  5. Page SQL results by keyset on timestamp. OFFSET returns 400 for personal API keys, and results cap at 50,000 rows

Questions

Which is better for AI agents, Fullstory or PostHog?

PostHog scores 68.4 (B) on agent readiness against Fullstory's 62.6 (B), and leads in every scored category.

Do Fullstory and PostHog need an API key?

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

Can an agent call Fullstory and PostHog without installing anything?

Yes. Fullstory has a hosted endpoint at https://api.fullstory.com and PostHog at https://us.posthog.com.

Are Fullstory and PostHog open source?

No open-source release is listed for Fullstory. PostHog is open source (MIT for the repository outside the `ee` directory, which has its own licence. PostHog Cloud is a hosted service under PostHog's terms).

Other comparisons with Fullstory or PostHog

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