# Flagsmith vs GrowthBook (slim)

> GrowthBook scores 68.6 (B) to Flagsmith's 61.2 (C) for feature flags. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/flagsmith-vs-growthbook.md (~5,300 tokens) · this version ~3,180 tokens · JSON https://www.anchorterminal.com/compare/flagsmith-vs-growthbook.json · canonical https://www.anchorterminal.com/compare/flagsmith-vs-growthbook
- 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
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

GrowthBook scores 68.6 (B) on agent readiness against Flagsmith's 61.2 (C), and leads in 5 of 7 scored categories. Both do feature flags.

- Flagsmith: C 61.2, rank #623 of 1510 · https://www.anchorterminal.com/tools/flagsmith.min.md
- GrowthBook: B 68.6, rank #279 of 1510 · https://www.anchorterminal.com/tools/growthbook.min.md
- Flagsmith, good for Feature flags and experiments for teams that want open source or self-hosting, managed by an agent through MCP.
- GrowthBook, good for Teams that want flags and experiments analysed against their own warehouse, with an open-source core and a self-hosted option. Ahead on Reliability, 86 against 65; Schema & documentation, 76 against 67; Agent ergonomics, 76 against 55; Security & auth, 76 against 65; Maintenance & community, 89 against 83. Also Free to start without a card.

| Category | Flagsmith | GrowthBook |
| --- | --- | --- |
| Reliability (16%) | 65 | 86 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 67 | 76 |
| Agent ergonomics (13%) | 55 | 76 |
| Security & auth (14%) | 65 | 76 |
| Payments & pricing (10%) | 40 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 83 | 89 |
| Transparency & trust (7%) | 77 | 75 |

| Fact (where they differ) | Flagsmith | GrowthBook |
| --- | --- | --- |
| Vendor | Bullet Train Ltd | GrowthBook, Inc. |
| Hosted endpoint | `https://mcp.flagsmith.com` | `https://mcp.growthbook.io/mcp` |
| Licence | BSD-3-Clause | MIT for the core and for the MCP server. Three enterprise directories in the main repository are under GrowthBook's enterprise licence. GrowthBook Cloud is a hosted service under the Customer Agreement |
| Tools exposed | 54 | 4 |
| Read-only variant documented | yes | no |
| llms.txt | no | yes |
| MCP registry | not listed | `io.github.growthbook/growthbook-mcp` |
| Last release | 2026-11-05 | 2026-10-06 |
| Terms last updated | 2026-09-01 | 2025-06-19 |
| Privacy policy last updated | 2023-10-01 | 2026-06-08 |
| Customer content may train models | not found in the text | yes |
| Terms restrict benchmarking | not found in the text | yes |
| Popularity | 6.6k stars | 8.5k stars, 1.3M npm/wk, 433k PyPI/wk |
| Agent reviews | none | 3.3/5 (4) |

Why the edge:
- Reliability, GrowthBook +21: Flagsmith 65 (Graded on Flagsmith Cloud with the hosted lines. Statuspage at status.flagsmith.com with components for the Edge API, Admin API, dashboard and website (20). In the 90 days from 8 August, an Admin and SDK API outage on 28 October marked critical, posted at 21:56 UTC and resolved at 22:12 with no cause given, and a minor delay in processing flag changes on 10 September. The posted span of the outage is 16 minutes and its start isn't stated, so we read it as one serious incident under an hour (15 of 30). The Management API limit of 500 requests a minute is documented (15). No 429 handling, Retry-After or idempotency guidance was found in the docs (0). A public SLA commits to 99.95 per cent monthly uptime with service credits (10). The Management API is generally available, but the MCP docs call the server an early release, so half (5 of 10). 20+15+15+0+10+5 = 65.); GrowthBook 86 (Graded on GrowthBook Cloud with the hosted lines. Instatus page at status.growthbook.io with three components (GrowthBook Cloud App, Api, CDN) and a notice history (20). No notices from August to October 2026, and the newest entry in the feed, re-read on 1 November, is still dated 21 August 2025. The MCP server is not a listed component, and the 2.2.0 changelog fixes intermittent 502s in HTTP mode that were not posted, so 25 of 30. API keys are limited to 60 requests a minute on Cloud, re-read in the API introduction and the OpenAPI spec on 1 November; since 19 October self-hosted servers can set per-key limits (15). The docs say only to try again later on 429. The server source sends standard RateLimit headers and the MCP server waits for `RateLimit-Reset` and retries three times, but no backoff guidance or idempotency keys were found in the docs (8 of 15). The pricing page lists a 99.99 per cent uptime SLA on Enterprise, re-read on 1 November. The SLA document itself was not found in public (8 of 10). The REST API's /v1 is described as stable and the MCP docs carry no beta label (10). 20+25+15+8+8+10 = 86.)
- Agent ergonomics, GrowthBook +21: Flagsmith 55 (54 tools, more than 30, with no toolsets or read-only subset; enterprise tools only appear where installed (5 of 25). List endpoints paginate with page and page_size (default 10) and filter by project, environment and search (14 of 20). Errors are Django REST Framework bodies with field messages, without a documented error code list (12 of 20). Every tool carries readOnlyHint, destructiveHint and idempotentHint derived from its HTTP method. No idempotency keys for POST (14 of 20). Few required parameters; official SDKs in more than a dozen languages, though they cover flag evaluation rather than the Management API (10 of 15). 5+14+12+14+10 = 55.); GrowthBook 76 (Four compact MCP tools, with skills loaded on demand and a /mcp/api endpoint that drops the skill tools (25). `limit` (default 10, maximum 100) and `offset` on 40 list operations, with filters by project, data source and status. No field selection was found, and the API tools return the raw response body (15 of 20). Errors are a status code and a `message` with no machine code. 422 marks a soft warning that can be resubmitted with `ignoreWarnings`, and the MCP server adds recovery hints for 401, 403, 404 and 429 (13 of 20). All four tools carry readOnlyHint and destructiveHint, and reads and writes are separate tools. Every write is marked destructive, and no idempotency keys were found (13 of 20). The API tools need one to three parameters. The SDKs cover flag evaluation in many languages, not the REST API (10 of 15). 25+15+13+13+10 = 76. Not re-read on 1 November beyond the MCP page and the spec, which still support each line.)
- Security & auth, GrowthBook +11: Flagsmith 65 (OAuth for interactive MCP clients with Flagsmith as the authorisation server, Organisation API keys in the Authorization header that act as admin or with chosen RBAC roles, and OIDC trust relationships that swap a CI token for a short-lived one. Granular key roles need Scale-Up or Enterprise, so a Free key is all-powerful (25 of 30). RBAC roles can limit a key to reads, and change requests put a flag change through approval on Scale-Up and Enterprise. There is no read-only switch on the MCP server itself (14 of 20). No prompt-injection guidance; tools return names, descriptions and trait values written by people (3 of 15). Audit logs record every admin action and stream by webhook, on Scale-Up and Enterprise (11 of 15). The docs say Flagsmith has a SOC 2 Type 2 report available on request, the terms promise a yearly third-party penetration test, and SECURITY.md routes reports to support email. No security.txt, bug bounty or public advisory process was found (12 of 20). 25+14+3+11+12 = 65.); GrowthBook 76 (OAuth with PKCE, dynamic client registration, refresh tokens and a revocation endpoint for the hosted MCP server. Since October the consent page asks what the connection may do, Read only, Human-in-the-Loop, Full access or a custom base role limited by project or environment, so a token no longer has to carry the user's full permissions. Secret Keys take any built-in or custom role with per-project overrides, environment limits and expiry, Personal Access Tokens can be scoped below their user (7 October), and since 21 October keys and tokens rotate in place with a grace period for the old secret. Secrets travel in headers only (30). A Read Only option, an endpoint with the API tools alone, and read and write tools with annotations. Since 16 October Human-in-the-Loop holds risky or destructive REST writes, including those from the hosted MCP endpoint, until a person confirms them on a linked page, and each decision goes to the audit log. Human-in-the-Loop is an Enterprise preset, and on a plan with only the admin role, which includes Free, Full access is the only option (18 of 20). No guidance on prompt injection was found, though the tools return names and descriptions that people wrote (3 of 15). Audit logging, with export, is on Enterprise only. Personal tokens attribute actions to a user, Secret Keys can name the member behind a request with `X-GrowthBook-Requested-By` (13 October), and the MCP server labels its API calls with `X-GB-MCP-*` headers (10 of 15). SOC 2 Type II, a disclosure process with a form and SECURITY.md, routine penetration testing and public GitHub advisories, the latest found on 19 August 2026. Rewards are merchandise only and www.growthbook.io/.well-known/security.txt still answered 404 on 1 November (15 of 20). 30+18+3+10+15 = 76. The new consent and confirmation pages were read on the MCP and API-keys docs on 1 November; we didn't sign in to see them.)
- Schema & documentation, GrowthBook +9: Flagsmith 67 (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`, so every tool has a JSON Schema input (25). No llms.txt (404) and no Markdown served for agents on docs.flagsmith.com; the docs are Markdown only in the repository (0). Tool descriptions say what each does and which feature-versioning mode it applies to, but rarely when not to use it, and only 153 of 624 operations carry a description (10 of 20). 57 enums and required fields in the spec, with some free-form value fields (10 of 15). Docs carry curl examples, but only 16 operations document a 400 and 6 a 404 (7 of 15). A /api/v1 path, release-please changelog and dated release notes (15). 25+0+10+10+7+15 = 67.); GrowthBook 76 (Public OpenAPI 3.1 spec, version 5.1.0, with 324 paths and 442 operations on 1 November (306 and 414 on 8 October), and Zod-typed inputs on all four MCP tools (25). llms.txt and a Markdown copy of each docs page (10). 441 of 442 operations have a summary and 205 have a description. The MCP tool descriptions say when to use each tool, and the bundled skills carry the workflows (13 of 20). The spec has 1,445 enums and marks required fields, but `growthbook_api_write` takes the path as a string and the body as a JSON string, and the docs still say the API tools do not validate payloads (9 of 15). The spec documents 200 responses on every operation, 202 for writes that wait for confirmation, 409 on 9 operations and 422 on 6. The introduction lists eight status codes and a `message` body (6 of 15). Path versions /v1 and /v2, 34 operations marked deprecated, GitHub releases, and an MCP changelog with breaking changes called out (13 of 15). 25+10+13+9+6+13 = 76.)
- Maintenance & community, GrowthBook +6: Flagsmith 83 (v2.290.0 was released on 5 November 2026 (30). 34 tagged releases between 8 August and 5 November (20). Commits land daily (60 since 8 August in the 60-commit clone), with a Discord server and support email. We couldn't read issue response times because GitHub's API refused us for its rate limit (15 of 25). Not in the official MCP registry, which returned no Flagsmith entry; official SDKs are current (8 of 15). Renovate updates, CI workflows for the API, frontend, docs and MCP, and a Trivy scan (10). 30+20+15+8+10 = 83.); GrowthBook 89 (MCP server 2.2.0 is dated 5 October 2026 and published to the registry on 6 October, GrowthBook 5.1.0 was tagged on 21 September 2026, and the main repository's commit releasing the JavaScript and React SDKs 2.0.0 landed on 30 October (npm not readable from here) (30). In the 90 days from 3 August, GrowthBook 5.0.1 (19 August) and 5.1.0, MCP 2.1.0 (10 August) and 2.2.0, and the SDK 2.0.0 release commit (20). The main repository's 200 newest commits run from 5 to 30 October 2026, and there is a community Slack. We did not read how quickly issues are answered (15 of 25). `io.github.growthbook/growthbook-mcp` is in the official MCP registry at 2.2.0, published 6 October 2026 and still latest on 1 November (15). The MCP repository runs CI on Node 22 and 26 and took dependency updates on 8 and 27 October 2026, both still unreleased. The package states Node 18 or later, which CI does not test (9 of 10). 30+20+15+15+9 = 89.)