Feature flag tools
A feature flag tool stores the on-off state and targeting rules for your features, then serves that configuration to your code through an SDK. Every tool on this page does that. Where they genuinely differ is what they charge you for, and there are three answers: nothing, your headcount, or your traffic. Your invoice is decided there, well before any feature on a comparison grid comes into it.
We make one of these, so read the rest accordingly. The figures below come from each vendor's published pricing page on the date shown, and each one has a calculator that shows the working.
The meter counts nothing
A flat plan quotes one number a month. Traffic can triple overnight and the invoice does not move. The trade is a set of ceilings, so the question to ask a flat vendor is which ceiling you hit first.
Featureflip
Flat monthly price. No seat charge, no evaluation charge.
Ours. Solo is free with 10 flags and 2 environments, Pro is $49 a month, Business is $149. Evaluations are unlimited on every tier, including the free one, because nothing counts requests.
Fits: Teams that want the bill to be a fixed line item and do not need experimentation statistics in the same tool.
Pricing checked August 4, 2026
ConfigCat
Flat tiers gated by two ceilings: products and monthly network traffic.
Predictable in the same way, with the ceilings drawn in different places. Forever Free covers 2 products and 20GB of traffic a month. Pro is $110 a month for 3 products, and SAML with SCIM is available on every tier rather than held back for an enterprise contract.
Fits: Small teams who want flat billing and need SSO early, provided the product count stays low.
Pricing checked July 24, 2026
The meter counts people
Per-seat billing scales with headcount, so it is the easiest of the three to forecast a year ahead. It also puts a price on letting more people near the flags, at the point where most teams are trying to get everyone comfortable using them.
Unleash
$75 per seat a month on Cloud.
Open-source-first, with a per-seat hosted plan and a quote-only enterprise tier. There is no free hosted tier, only a 14-day trial, and the cloud plan includes an allowance of 53 million API requests before request pricing enters the picture.
Fits: Teams committed to the open-source edition, or small groups who would rather pay per person than watch a traffic meter.
Pricing checked July 29, 2026
GrowthBook
$40 per seat a month on Cloud Pro, free for the first three users.
Experimentation is the centre of gravity here, with flags as the delivery layer under it. It runs a warehouse-native statistics engine offering both Bayesian and frequentist methods, and the paid cloud tier is capped at 50 users before it goes to a quote. Self-hosting the open-source edition costs nothing but your own infrastructure.
Fits: Teams that want flags and a real statistics engine in one place and are willing to pay per editor for it.
Pricing checked July 31, 2026
The meter counts traffic
This is the group that surprises people, because the unit differs at every vendor and none of them is a straightforward user count. LaunchDarkly runs two meters at once, on open service connections and on browser users. Flagsmith counts API requests. PostHog charges for every individual flag request, which makes it the most sensitive of the three to how your front end is written. Budgeting against the wrong unit is how a forecast ends up out by an order of magnitude.
LaunchDarkly
Two meters at once: $12 per service connection and $10 per 1,000 client-side monthly active users.
The category incumbent, sold as a platform with experimentation and observability attached. The Developer tier is free up to 5 service connections and 1,000 client-side monthly active users, and enterprise tiers are quote-only. Running both meters together is what makes the bill hard to predict before you are on it.
Fits: Large organizations that need the surrounding platform, procurement-grade compliance, and can absorb usage-based billing.
Pricing checked July 22, 2026
Flagsmith
Tiered monthly API requests, with seats fixed per tier.
Open-source with a hosted plan and a full self-host path. Free covers 50,000 API requests and one team member. Start-Up is $45 a month with 3 seats and a million requests, and there is no way to buy a fourth seat without moving to Scale-Up. Requests past a tier bill at $50 per additional million.
Fits: Teams who want the open-source option in reserve, with request volume they can bound.
Pricing checked July 23, 2026
PostHog
Per flag request on a graduated curve, after a free first million a month.
Flags are one product inside an analytics and session-replay suite, and they carry no seat cost or subscription of their own. The first million requests each month are free. Past that the rate steps down as volume climbs, so the shape of your traffic matters more than its total.
Fits: Teams already running PostHog for analytics, who would rather add flags there than operate a second tool.
Pricing checked July 30, 2026
How to narrow the list
Four questions separate these tools faster than a feature matrix will.
What does the meter count, and does your product multiply it?
A flag checked once per request in a backend service is a different bill from the same flag checked on every render in a browser. Client-side evaluation multiplies request-metered plans, and it is the single most common way a quote turns out to be wrong.
Where is the ceiling, and what happens at it?
Some ceilings are an overage rate you can absorb. Others are a hard stop that forces a tier upgrade, which is how a fourth teammate can cost more than the three before them.
Do you need experimentation, or delivery?
Serving a sticky 50/50 split is a flag job and every tool here does it. Deciding which variation won, with statistics you would defend in a review, is a different product. If you need both in one place, that narrows the list quickly. If your analytics stack already answers it, paying for a second statistics engine is money spent twice. Our A/B testing use case draws that line in more detail.
Hosted or self-hosted?
Self-hosting an open-source edition removes the licence line and adds an operational one. The honest comparison is the licence against a database, upgrades and an on-call rotation, because a flag service sits in the path of every feature you ship. The build versus buy guide works through that arithmetic.
Go deeper on any of them
This page is the shortlist. Three clusters sit underneath it, each answering a different question about the same set of tools.
Comparisons
Feature-by-feature against each platform, with a verdict per team profile.
Alternatives guides
For teams already leaving a platform and choosing where to land.
Cost calculators
Put your own numbers through a vendor's rate card and read the annual figure.
If the pricing models themselves are what you are trying to understand, the deep dive on feature flag pricing covers all three meters and the traps in each.
Frequently asked questions
What is a feature flag tool?
A feature flag tool stores the on-off state and targeting rules for features in your application, and serves that configuration to your code through an SDK. It lets you turn a feature on for some users and off for others without deploying again, and turn it off entirely when something breaks.
How much do feature flag tools cost?
Free tiers are common and paid plans typically start between $40 and $110 a month for a small team. The spread comes from what each vendor meters rather than from the headline price, so two tools quoting a similar starting figure can bill very differently once traffic or headcount grows.
What is the difference between flat and usage-based feature flag pricing?
A flat plan charges one price a month regardless of how many times your code checks a flag. A usage-based plan meters something that grows with your product, such as API requests, flag requests, open service connections, or client-side monthly active users. Flat pricing is predictable and bounded by ceilings. Usage-based pricing starts cheaper and moves with your traffic.
Which feature flag tools have a free tier?
Featureflip, ConfigCat, Flagsmith, PostHog, GrowthBook and LaunchDarkly all publish a free tier, though the caps differ sharply: 1 team member at Flagsmith, 3 users at GrowthBook, 5 service connections and 1,000 client-side monthly active users at LaunchDarkly. Unleash has no free hosted tier and offers a 14-day trial instead.
Can you self-host a feature flag tool?
Flagsmith, Unleash and GrowthBook all publish an open-source edition you can run yourself, and self-hosting removes the licence cost entirely. It replaces that cost with your own: a database, an uptime commitment, upgrades, and an on-call rotation for a service that sits in the request path of every feature you ship.
Do I need a feature flag tool, or should I build one?
A boolean in a config file is a reasonable first flag and plenty of teams stop there. The cost of building arrives later, in the parts that are dull to write and unpleasant to get wrong: per-environment configuration, sticky percentage bucketing, an audit trail, and an SDK that keeps serving the last known values when the network is down.
Try the flat one
Featureflip is one price a month whatever your traffic does. Solo is free with 10 flags and 2 environments, and it does not ask for a card.