Flagsmith vs GrowthBook
Both are alternatives to LaunchDarkly. Here's how they stack up — verified facts, no spin.
Also searched as GrowthBook vs Flagsmith — same comparison, one verdict.
Flagsmith and GrowthBook are closely matched on ownership (90 vs 83) — this one comes down to pricing and to which trade-offs below you can live with.
Flagsmith
BSD-licensed flags with remote config, and no copyleft to reason about.
Flagsmith covers feature flags, remote configuration and A/B testing under BSD-3-Clause — the most permissive licence in this comparison, which removes the legal reading that AGPL requires. It self-hosts on Docker or Kubernetes, supports multiple environments and organisations natively, and its edge API keeps evaluation latency low without you building a caching layer. Around 6.5k stars. Its remote-config support is the underrated part: shipping a configuration value to clients without a release is the same mechanism as a flag, and having both in one tool removes a category of bespoke plumbing.
GrowthBook
Flags plus a real statistics engine — the experimentation answer.
GrowthBook is the option to look at when the reason you want flags is experiments rather than toggles. It runs A/B tests against your existing data warehouse — Snowflake, BigQuery, Redshift, Postgres — so the analysis happens where your data already lives instead of in a second copy, and it offers Bayesian and frequentist statistics rather than one opinionated method. Around 8.1k stars. The licence needs stating precisely: the core is MIT, but three enterprise directories are carved out under a separate commercial licence, so it is MIT-with-exceptions rather than plain MIT.
Side by side
10 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Flagsmith | GrowthBook | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 90 | 83 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | BSD-3-Clause (open core; paid hosted and enterprise tiers) | MIT core, with enterprise directory carve-outs |
| Pricing | Open source free and self-hostable. Hosted plans have a free tier and paid tiers above it. | Self-hostable core free. Cloud and enterprise tiers are paid. |
| RAM to run it wellThe figure that actually matters, not the vendor's minimum. | 4 GB | 4 GB |
| Realistic running costWhat the box costs each month if you run it yourself. | $24–40/mo plus PostgreSQL, against LaunchDarkly pricing that scales per seat and per monthly active user | $20–35/mo, against LaunchDarkly pricing that starts high and scales per seat and per MAU |
| Setup timeHonest first-install estimate, not the marketing quickstart. | 2 hours | 2 hours |
| Ongoing maintenanceThe part nobody budgets for. | Low to moderate. | Low to moderate. |
Flagsmith edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Weighing both against staying on LaunchDarkly? Is LaunchDarkly free? What it actually costs →
Flagsmith
Strengths
- +BSD-3-Clause — the most permissive licence here, no copyleft to interpret
- +Feature flags and remote config in one product
- +Multi-environment and multi-organisation support built in, not bolted on
- +Edge API keeps evaluation fast without custom caching
Trade-offs
- −Smaller community than Unleash and fewer third-party integrations
- −Experimentation is basic next to LaunchDarkly
- −Advanced features are reserved for the paid tiers
- −Self-hosted deployment needs Postgres and some tuning at scale
GrowthBook
Strengths
- +Genuine statistics engine — Bayesian and frequentist, not a toggle with a chart
- +Runs experiments against your existing warehouse, no data duplication
- +Warehouse-native means no second source of truth to reconcile
- +Self-hostable with a real free path
Trade-offs
- −Enterprise directories are carved out of the MIT licence
- −Heavier to set up than the pure flag tools — you need a warehouse
- −Flag management is less polished than Unleash's
- −Overkill if you only want to turn features on and off
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Flagsmith
if a lower exit cost matters more to you than any single feature, and bSD-3-Clause — the most permissive licence here, no copyleft to interpret.
Choose GrowthBook
if genuine statistics engine — Bayesian and frequentist, not a toggle with a chart.
Neither, yet
if both carry a real cost you should weigh first — smaller community than Unleash and fewer third-party integrations, and enterprise directories are carved out of the MIT licence. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
What it takes to run these yourself
Real requirements and honest running costs, not the vendor quickstart.
Flagsmith vs GrowthBook — common questions
Is Flagsmith a better fit than GrowthBook for feature flags & experimentation?
It depends on what you are optimising for, and the honest split is this: Flagsmith scores 90 to GrowthBook's 83 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. GrowthBook earns its place on a different axis — genuine statistics engine — Bayesian and frequentist, not a toggle with a chart. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Flagsmith keeps its data local or in open formats, so leaving is an export rather than a negotiation. GrowthBook is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Flagsmith or GrowthBook?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Flagsmith and GrowthBook both alternatives to LaunchDarkly?
Yes — both appear in our LaunchDarkly comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off LaunchDarkly and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-07-31. Licenses and pricing change — spotted something out of date? That's a correction we want.