# Flagsmith (slim)

> Flagsmith is an open-source feature flag, remote config and experimentation service from Bullet Train Ltd. Teams use it on Flagsmith Cloud or self-hosted, through SDKs, a Management API and a remote MCP server.

- Full: https://www.anchorterminal.com/tools/flagsmith.md (~7,300 tokens) · this version ~1,680 tokens · JSON https://www.anchorterminal.com/tools/flagsmith.json · canonical https://www.anchorterminal.com/tools/flagsmith
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07 · pricing https://www.anchorterminal.com/tools/flagsmith#pricing · reviews https://www.anchorterminal.com/tools/flagsmith#reviews
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

**C · 61.2/100 · rank #620 of 1486 · #12 in Product analytics & experimentation · not agent-ready · confidence medium**


Assessment: Flagsmith pairs a BSD-licensed core with a hosted MCP server whose 54 tools come from its OpenAPI spec and carry read and destructive hints. A public 99.95 per cent SLA and SOC 2 report back the Cloud service. The MCP server is still an early release, and fine-grained key roles need a paid Scale-Up or Enterprise plan.

## Facts

- Kind: HTTP API · vendor: Bullet Train Ltd · category: Product analytics & experimentation · legal entity: Bullet Train Ltd · provenance 86/100
- Endpoint: `https://mcp.flagsmith.com` (HTTP, Streamable HTTP, stdio)
- Auth: OAuth or key · pricing: Freemium · x402: no · licence: BSD-3-Clause
- Benchmark probes: not run yet, so Performance is pending
- Live, from our pollers (not part of the score): up at 2026-11-07 17:49 UTC · uptime 30 days 100.0% (195 probes) · p50 27 ms · p95 103 ms over 24 hours
- Vendor status page: no problems reported, All Systems Operational (2026-11-07 17:45 UTC)
- Surface listed: Flagsmith Cloud's Management API at api.flagsmith.com and the hosted MCP server at mcp.flagsmith.com, read from docs.flagsmith.com, the Flagsmith/flagsmith repository (docs, MCP source and openapi.yaml), the pricing, SLA and legal pages and status.flagsmith.com on 6 November 2026. No account was made and no tool was called
- MCP tools: 47 core tools for flags, segments, segment overrides, multivariate options, feature versions, change requests, releases, code references, evaluation data, invites and experiments, plus 7 enterprise tools that appear only when those modules are installed
- Experimentation: Native experiments with a managed warehouse and built-in statistics, exposed through MCP tools marked beta, with metric creation and results reads
- Rate limits: 500 Management API requests a minute by default, configurable on self-hosted installs with USER_THROTTLE_RATE. SDK traffic is limited only by plan, with 7 days' warning before a Free plan is blocked
- Governance: Roles, permissions, change requests and audit logs on Scale-Up and Enterprise; SAML on Scale-Up and Enterprise; audit log webhooks
- Self-hosting: BSD-3-Clause source on GitHub with Docker images; the self-hosted API sends a count-only telemetry heartbeat to api.flagsmith.com unless ENABLE_TELEMETRY is set to false
- Legal entity: Bullet Train Limited trading as Flagsmith, company number 12353266, 66 Paul Street, London, under English law
- Prices: Start-Up plan $45 per month (plan); Scale-Up plan $300 per month (plan); Extra API calls $0.05 per 1,000 requests; Extra Scale-Up team member $50 per seat per month

- Scores: Reliability 65, Performance pending, Schema & documentation 67, Agent ergonomics 55, Security & auth 65, Payments & pricing 40, Task success pending, Maintenance & community 83, Transparency & trust 77 · negative events -2 · total over the 7 assessed categories
- Why: Reliability, Graded on Flagsmith Cloud with the hosted lines. · Schema & documentation, openapi.yaml in the repository is OpenAPI 3.1 with 624 operations, and the MCP server builds its 54 tools from the operations tagged `mcp`… · Agent ergonomics, 54 tools, more than 30, with no toolsets or read-only subset; enterprise tools only appear where installed (5 of 25). · Security & auth, OAuth for interactive MCP clients with Flagsmith as the authorisation server, Organisation API keys in the Authorization header that act as… · Payments & pricing, No x402, MPP or L402 (0). · Maintenance & community, v2.290.0 was released on 5 November 2026 (30). · Transparency & trust, BSD-3-Clause for the core and the MCP server; the about page says most of the product is under that licence and some CI runs with private pa…
- Sources: 13, open questions: 6, both in the full twin
- Capabilities: analytics.flags, analytics.experiments, analytics.events
- JSON: https://www.anchorterminal.com/api/v1/tools/flagsmith.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/flagsmith.svg` or a link to https://www.anchorterminal.com/tools/flagsmith from a page on flagsmith.com or one of its subdomains, or the README at the root of github.com/Flagsmith/flagsmith, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.
- Support: Discord https://discord.gg/hFhxNtXzgm; support@flagsmith.com; https://docs.flagsmith.com/support; https://status.flagsmith.com; more in the full twin

## Before you call it

1. Send the key as `Authorization: Api-Key <key>`; the `Api-Key ` prefix is required and a bare key fails
2. Check whether the environment uses v2 feature versioning before choosing between segment-override and version-state tools
3. Use a key with a read-only RBAC role for analysis tasks, since a Free plan key has organisation admin rights
4. Pace Management API calls under 500 a minute; no Retry-After guidance is documented
5. Treat experiment results as possibly null until Flagsmith has computed them

## Connect

```bash
curl -H "Authorization: Api-Key $FLAGSMITH_ORG_KEY" https://api.flagsmith.com/api/v1/projects/
```

```bash
claude mcp add --transport http flagsmith https://mcp.flagsmith.com
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/flagsmith

## Similar tools

| Tool | Grade | Score | Shared capabilities | Slim |
| --- | --- | --- | --- | --- |
| Statsig | BB | 72.4 | analytics.experiments, analytics.flags, analytics.events | https://www.anchorterminal.com/tools/statsig.min.md |
| Amplitude | B | 69.3 | analytics.experiments, analytics.flags, analytics.events | https://www.anchorterminal.com/tools/amplitude.min.md |
| Harness Feature Management & Experimentation | B | 69.2 | analytics.flags, analytics.experiments, analytics.events | https://www.anchorterminal.com/tools/harness-fme.min.md |
| GrowthBook | B | 68.6 | analytics.experiments, analytics.flags, analytics.events | https://www.anchorterminal.com/tools/growthbook.min.md |
| PostHog | B | 67.4 | analytics.events, analytics.experiments, analytics.flags | https://www.anchorterminal.com/tools/posthog.min.md |


## Panel reviews (0, desk reviews from public material, no calls made)