Layer 3 · self-hosting reality check
What it actually takes to self-host Flagsmith
The docs say 1 GB. In practice you want 4 GB. Here is the honest version — real requirements, real monthly cost, what you will be maintaining, and the one thing that catches people out.
Usually reached from LaunchDarkly alternatives, where Flagsmith is one of the picks.
| RAM — documented minimum | 1 GB |
|---|---|
| RAM — what it really needs | 4 GB |
| CPU | 2 vCPU |
| Disk | Small |
| Monthly cost | $24–40/mo plus PostgreSQL, against LaunchDarkly pricing that scales per seat and per monthly active user |
| Setup time | 2 hours |
| How you install it | docker compose — API, frontend, PostgreSQL |
| Ongoing maintenance | Low to moderate. |
| Where it stops scaling | Very well with local evaluation, because the server then serves configuration rather than traffic. |
The thing that catches people out
The SDKs run either in local-evaluation mode, which is fast and resilient, or remote mode, which calls the API on every flag check. Several SDKs default to remote — so a flag check in a hot path adds a network round trip and your feature-flag service quietly becomes a latency dependency of your application. Switch to local evaluation with polling before flags go anywhere performance-sensitive.
When not to self-host Flagsmith
You need enterprise governance and approval workflows, which sit in the paid tiers rather than the open-source core.
Every guide here carries this section. A site that only ever tells you to self-host is selling something — the useful answer is sometimes no.
Other Layer 3 self-hosting guides
Common questions
- How much RAM does Flagsmith actually need?
- 4 GB in practice. The documented minimum is 1 GB, which is the figure at which the process starts rather than the figure at which it works under real use. 2 vCPU alongside it.
- What does self-hosting Flagsmith cost per month?
- $24–40/mo plus PostgreSQL, against LaunchDarkly pricing that scales per seat and per monthly active user This is commodity VPS pricing and excludes your time, which is the larger cost for most people — budget for low to moderate.
- How long does it take to set up Flagsmith?
- 2 hours, via docker compose — API, frontend, PostgreSQL.
- When should I NOT self-host Flagsmith?
- You need enterprise governance and approval workflows, which sit in the paid tiers rather than the open-source core.
- What is the most common mistake when self-hosting Flagsmith?
- The SDKs run either in local-evaluation mode, which is fast and resilient, or remote mode, which calls the API on every flag check. Several SDKs default to remote — so a flag check in a hot path adds a network round trip and your feature-flag service quietly becomes a latency dependency of your application. Switch to local evaluation with polling before flags go anywhere performance-sensitive.