Flagsmith vs Optimizely Experimentation

Flagsmith 40

No x402, MPP or L402 (0). Plan prices and the per-million overage are public without login, though the page gives two overage rates for Start-Up ($50 per million and $7 per 100,000) (20). A $0 Free plan with 50,000 requests a month and a free BSD-3-Clause self-hosted edition. The pricing page doesn't say whether a card is needed, but the Free plan has no charge and the self-hosted edition needs no account (20). A person signs up in a browser, then approves OAuth or creates a key (0). 0+20+20+0 = 40.

Optimizely Experimentation 0

No x402, MPP or L402 (0). No price is published. The plans page says every plan is individually packaged and leads to a demo request (0). No free plan or trial was found on the plans page, the product pages or the docs (0). Access needs a subscription and a browser sign-in through Opti ID (0).

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.

Optimizely Experimentation 83

Graded on the hosted service with the hosted lines. Statuspage at status.optimizely.com with 174 components, among them Optimizely REST API, Results API, Events API, Snippet Delivery and Snippet Building for Feature and Web Experimentation (20). From 4 August to 2 November 2026 its history shows three incidents that reach Experimentation, all minor. On 25 August a provider's network fault degraded service for a subset of customers in Southeast Asia (05:15 to 07:37 UTC). On 17 September Optimizely Identity sent users to the wrong SSO page for about 3 minutes, which touches the sign-in the MCP server uses. On 15 October snippet publishing for Web Experimentation was delayed for some customers while existing experiences kept serving. The 23 July Okta sign-in incident has left the window (20 of 30). The Feature Experimentation API is limited to 2 requests a second and 120 a minute, the Optimizely API to 100 a minute and the results endpoints to 20 a minute. No limit was found for the MCP server (13 of 15). The API conventions page documents 429 - Too Many Requests with X-RATELIMIT-LIMIT, X-RATELIMIT-REMAINING and X-RATELIMIT-RESET on every response and says to wait for the reset, but no idempotency key or safe-retry guidance for writes was found (10 of 15). The Service Level Agreement V 2024-05 gives credits from 10 per cent once downtime passes 43 minutes in a month, capped at 50 per cent (10). The REST APIs are versioned and the MCP pages carry no beta label (10). 20 + 20 + 13 + 10 + 10 + 10 = 83.

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.

Optimizely Experimentation 68

The MCP server lists eight tools since exp_program_reporting_execute_query was added on 13 October 2026, which is 25 on the checklist. We took 2 off because the tool definitions were unread and their size is unknown (23 of 25). per_page up to 100 and page on the v2 lists, page_token, sort and query on the flags list, and time windows on results (17 of 20). The Optimizely API returns code, message and a uuid, and the Feature Experimentation API returns a problem detail object. MCP error results were unread (13 of 20). No idempotency keys were found and the tool annotations were unread. The docs say the agent confirms project, environment and details before a change, which is client behaviour, and entities are archived through the lifecycle tool (5 of 20). The MCP server needs only a URL. The official SDKs in eleven languages evaluate flags and log events and do not cover the management APIs (10 of 15).

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.

Optimizely Experimentation 76

The Swagger 2.0 file for the Optimizely API sits at api.optimizely.com, whose robots.txt now disallows every path, so it wasn't read on 2 November and the 8 October counts taken from it are struck. Each reference page on docs.optimizely.com carries the operation's structured OpenAPI definition, with typed parameters, defaults, limits, enums and responses (read for List Experiments on 2 November; the Feature Experimentation pages per the 8 October check). We could not read the MCP tool schemas, which need a sign-in (20 of 25). llms.txt and a Markdown copy of every docs page (10). Reference pages describe each operation's purpose. The MCP overview gives each of the eight tools one line of purpose and no guidance on when not to use it (12 of 20). Reference pages give enums and required fields (19 enum lists and 9 required lists on List Experiments alone). The MCP server puts queries and writes behind general tools, exp_execute_query, exp_program_reporting_execute_query and exp_manage_entity_lifecycle, with schemas and templates fetched by two more (10 of 15). Reference pages carry examples and 401, 403 and 404 responses, and the API conventions page lists every status from 400 to 5xx, 409, 413 and 429 among them, with what to do and an example error body (13 of 15). Versions are in the path (/v2, /flags/v1) and each product has dated release notes with an RSS feed. No changelog for the APIs alone was found (11 of 15). 20 + 10 + 12 + 10 + 13 + 11 = 76.

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.

Optimizely Experimentation 78

The newest Feature Experimentation release notes are dated 15 October (Flutter SDK 4.0.0) and 13 October 2026 (a new MCP tool), 18 and 20 days before this check (30). Feature Experimentation notes on 6 August, 3 September, 13 and 15 October 2026, monthly Web Experimentation notes, plus @optimizely/optimizely-sdk 6.6.0 (3 September) and 6.6.1 (18 September) and optimizely-sdk 5.7.0 for Python (tag 7 September) (20). Closed service with public release notes, an RSS feed and a support centre. We did not read how quickly questions are answered (9 of 15). Official SDKs are current in eleven languages. The MCP server is not in the official MCP registry, where a search for optimizely returns nothing on 2 November (12 of 15). The JavaScript SDK repository has six CI workflow files and 9 commits since 4 August 2026, the last on 29 October (7 of 10). 30 + 20 + 9 + 12 + 7 = 78.