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Flagsmith

Open-source feature flags and A/B tests, cloud or self-hosted

Open source · $45Developer tools
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Flagsmith is a developer tools tool for Developers and Small businesses, offered as open source ($45/mo). Based in United Kingdom. Popular alternatives include Omnara, Overmind, beacon.sh.

About Flagsmith

Flagsmith is an open-source feature flag and remote config platform based in London. It grew out of Solid State Group, founder Ben Rometsch's software agency, whose team built it after failing to find a suitable open-source flag service; the BSD-3-Clause repository dates from 2018. Teams use it to switch features on or off, change config values and roll out to segments or percentages without a redeploy.

Every plan has unlimited flags, environments and segments. Paid tiers add scheduled flags, multivariate testing and integrations, and Scale-Up adds SAML SSO, roles, change requests and audit logs. SDKs cover JavaScript, React, iOS, Android, Flutter, Python, .NET, Go and Rust, Flagsmith is an OpenFeature provider, and integrations include Datadog, New Relic, Sentry, Amplitude, Mixpanel, Jira and Terraform. It runs as cloud in eight regions, private cloud, or self-hosted with Helm or an OpenShift operator.

It fits teams that want self-hostable open-source flags with a paid cloud fallback. PostHog bundles flags with product analytics, LaunchDarkly is the pricier enterprise incumbent, and Unleash is the closest open-source rival. The Free cloud plan allows one team member, and governance starts at Scale-Up.

On October 21, 2026 Flagsmith launched Flagsmith Experiments on Product Hunt, finishing #10 of the day. It adds Bayesian A/B testing on existing flags with chance-to-beat and lift for one primary metric, audiences from segments or Amplitude and Mixpanel cohorts, and ClickHouse or Databricks warehouses. Buying tip: yearly billing cuts Start-Up from $45 to $40 a month.

Key features of Flagsmith

  • Feature flags and remote config with user, segment and percentage targeting
  • Bayesian A/B experiments built directly on existing flags
  • Scheduled flags, multivariate flags and change requests
  • SDKs for JavaScript, React, iOS, Android, Flutter, Python, Go and Rust
  • OpenFeature provider for cloud, private cloud and self-hosted setups
  • Audit logs, roles and permissions for governance
  • Cloud in eight regions with a global edge API
  • Self-hosting via Helm chart or OpenShift operator

Pros and cons

Pros

  • Open source under BSD-3-Clause with a real self-hosting path
  • Unlimited flags, environments and segments on every plan
  • Wide SDK coverage including mobile and Flutter
  • Grace period before overage charges on paid plans
  • Experiments reuse flags instead of a separate testing tool

Cons

  • Free cloud plan allows only one team member
  • SSO, roles and audit logs require Scale-Up at $250 or more a month
  • Experiments v1 supports one primary metric per test
  • Warehouse support for experiments limited to ClickHouse and Databricks
  • Request-based limits need monitoring on high-traffic apps

Flagsmith pricing

Flagsmith uses a open source model. A 14-day free trial is available.

PlanPriceIncludes
Free$050k requests/mo, 1 team member, 1 project
Start-Up$45 / mo$40/mo billed yearly; 1M requests, 3 members, A/B testing
Scale-Up$300 / mo$250/mo yearly; 5M requests, SAML SSO, roles, audit logs
EnterpriseCustomPrivate cloud or on-prem, SLA, onboarding, priority support

Source: www.flagsmith.com · checked on Oct 22, 2026

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How Flagsmith compares in Developer tools

Rank by votes
#2 / 101

0 votes from members

Starting price
$45

125% above the category median ($20/mo)

Free alternatives
23

Free or open-source tools in Developer tools

Flagsmith ranks #2 of 101 developer tools tools by community votes and is priced above most tools in the category.

Common use cases

  1. 1Gradual rollouts and canary releases behind feature flags
  2. 2Killing a broken feature instantly without a redeploy
  3. 3Changing mobile app config without an app store review
  4. 4Running A/B tests on flags with results from your warehouse
  5. 5Self-hosting flags in a regulated or air-gapped environment

Best for

Engineering teams that want open-source, self-hostable feature flags with optional cloud hosting and built-in experiments.

Not ideal for

Teams that want flags bundled with product analytics or a large enterprise vendor ecosystem (PostHog, LaunchDarkly).

Integrations

  • Datadog
  • New Relic
  • Grafana
  • Sentry
  • Amplitude
  • Mixpanel
  • Jira
  • Terraform

Our take

Flagsmith is one of the most practical open-source feature flag platforms, and Experiments now covers basic A/B testing on the same flags. Self-host it for control, or choose Start-Up cloud for small teams and budget Scale-Up once you need SSO and audit logs.

FAQ

What is Flagsmith?
Flagsmith is a Developer tools tool: Open-source feature flags and A/B tests, cloud or self-hosted.
How much does Flagsmith cost?
Flagsmith is Open source; there is no mandatory paid plan.
What are the best alternatives to Flagsmith?
Community-listed alternatives to Flagsmith include Omnara, Overmind, beacon.sh, fastbrowse.
Does Flagsmith have a free trial?
Yes, Flagsmith offers a 14-day free trial.
What does Flagsmith integrate with?
Flagsmith integrates with Datadog, New Relic, Grafana, Sentry, Amplitude, Mixpanel and more.
Which platforms does Flagsmith support?
Flagsmith is available on web.
Who is Flagsmith for?
Engineering teams that want open-source, self-hostable feature flags with optional cloud hosting and built-in experiments.

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