claude-skills/engineering/skills/feature-flags-architect/references/provider_comparison.md

Provider comparison

Five mainstream providers + DIY. Pick based on flag count, targeting needs, compliance, and self-hosting requirements.

At-a-glance matrix

Provider	Flag count sweet spot	Targeting	A/B testing	Audit log	Self-host	OSS	Pricing model
LaunchDarkly	100+	Best-in-class	Yes (Galaxy)	Full SOC2 audit trail	Edge SDK only	No	Per-MAU, expensive
GrowthBook	20-500	Good	Yes (built-in)	Yes	Yes (Docker/k8s)	Yes (MIT)	Free OSS + Cloud per-MAU
Statsig	50-500	Good	Best-in-class	Yes (paid)	No	No	Free tier (1M events), then per-MAU
Unleash	10-200	Good	Limited	Yes (Enterprise)	Yes (Docker/k8s)	Yes (Apache 2)	Free OSS + Hosted/Enterprise
Flipt	5-100	Basic	No	Limited	Yes (Docker/k8s)	Yes (MIT)	OSS only
DIY	<50	None to basic	None	Whatever you build	Always	N/A	None

When to choose each

LaunchDarkly

Choose if:

• Enterprise team with 100+ flags across many services
• Compliance requires SOC2 / ISO 27001 / FedRAMP audit logs
• Need fine-grained targeting (cohorts, custom attributes, percentages by attribute)
• Need experimentation + targeting + audit in one platform
• Budget for enterprise tooling ($20-100k/year typical)

Avoid if:

• Small team / <50 flags (overkill)
• Strict data residency (no on-prem; relays only)
• Low budget

GrowthBook

Choose if:

• Mid-market team that wants OSS option for self-hosting
• Need built-in A/B testing with proper stats (frequentist + Bayesian)
• Want SQL-based experimentation (define metrics from your warehouse)
• Self-host on k8s or run their hosted Cloud

Avoid if:

• Need real-time targeting at edge (use LD or Statsig)
• Need enterprise audit features (Cloud only)

Statsig

Choose if:

• Growth/product team for whom experimentation is the core use
• Need advanced stats (CUPED, sequential testing)
• Want generous free tier (good for early-stage)
• Want best-in-class metric library and platform-side experimentation logic

Avoid if:

• Strict data residency / self-host requirement (no on-prem option)
• Don't need experimentation, just toggles (overkill)

Unleash

Choose if:

• OSS-first culture; want to self-host
• Dev-friendly with good SDKs and a clean API
• Don't need full A/B testing platform
• Need Open Source license for compliance (Apache 2)

Avoid if:

• Need experimentation + stats out of the box
• Need enterprise-grade audit (Enterprise tier only)

Flipt

Choose if:

• Lightweight needs, <100 flags
• k8s-native (Flipt is operator-friendly)
• Want pure OSS, no commercial component
• Don't need A/B testing

Avoid if:

• Need targeting beyond simple boolean rules
• Need experimentation
• Need analytics or audit features

DIY (env vars / config file)

Choose if:

• <50 flags total
• No targeting beyond enabled: true/false
• No A/B testing needs
• Want zero external dependencies
• Strict cost control

Implementation:

# config/flags.yaml
flags:
  new-checkout: { enabled: true, owner: jane@team }
  payment-v2:   { enabled: false, owner: bob@team, kill_switch: PagerDuty alert "payment-v2 SEV1" }

Or env-var based:

FLAG_NEW_CHECKOUT=true
FLAG_PAYMENT_V2=false

Avoid if:

• Flag count growing past 50
• Need percentage rollouts (you'll re-implement provider logic poorly)
• Need audit log (compliance)
• Multiple teams / multiple deploy cadences

Cost rule of thumb

Team stage	Typical monthly cost
Pre-seed / solo	$0 (DIY or OSS)
Seed (Series A)	$0-200 (Statsig free tier, Unleash OSS)
Series B-C	$500-3,000 (GrowthBook Cloud, Unleash Pro)
Series D+ / Enterprise	$5,000-20,000+ (LaunchDarkly, Statsig Pro, Unleash Enterprise)

Migration paths

Easy migrations:

• DIY → Unleash / Flipt (similar simple model)
• Unleash ↔ GrowthBook (similar feature surface)

Hard migrations:

• LaunchDarkly → anywhere (proprietary targeting language)
• Statsig → anywhere (proprietary experimentation logic)

Lock-in mitigation: Wrap your provider behind an interface in code:

interface FlagProvider {
  isEnabled(name: string, context?: UserContext): boolean;
  getValue<T>(name: string, defaultValue: T, context?: UserContext): T;
}

Swap providers by writing a new adapter, not by rewriting every call site.

Build-vs-buy threshold

Buy a provider when:

• Flag count > 50
• Multiple teams need to manage flags independently
• Targeting needs include percentages, cohorts, or custom attributes
• Compliance requires audit log
• Need real-time updates without redeploy

Build (DIY) when:

• All of the above are NO

Selection checklist

Before signing a contract:

• Estimate flag count over 12 months
• List required targeting dimensions (user/account/geo/%/custom)
• Confirm SDK availability for every language in your stack
• Check edge latency (p99 < 50ms for prod)
• Verify failure mode if provider is unreachable (default-to-safe)
• Confirm SOC2 / data residency if needed
• Run a 30-day proof-of-concept; measure actual cost at projected MAU