Flagsmith vs Unleash: A Detailed Comparison

Flagsmith vs Unleash at a glance

You’d be forgiven for thinking that Flagsmith and Unleash are similar—both are open-source feature flagging solutions, both are built with engineers in mind. And, from a features standpoint, they have a lot in common (with some key differences).

But each has its strengths, and, depending on what you’re looking for, either one might be right for you. Engineers tend to choose Flagsmith over Unleash because of: 

Integrations

Flagsmith has significantly more native integrations than Unleash, especially when it comes to data analytics providers (Unleash doesn't have any). Unleash might not be the right solution for you if you’re interested in understanding how flags affect user behaviour. 

Stability

Flagsmith is bootstrapped and profitable, as opposed to VC-funded—like Unleash—which means Flagsmith has a lot more stability. No board-mandated price hikes or unsustainable hiring practices that lead to layoffs and product chaos. This also means Flagsmith can be more hands-on when it comes to technical support and roadmap requests.

Cost

With Flagsmith, you’re not paying for venture-backed booleans. Bootstrapping allows Flagsmith to offer much more competitive pricing than Unleash. 

Real-time feature updates

Flagsmith offers real-time flags, meaning when you turn a feature on or off, flag changes will instantly synchronise across all platforms and environments. Unleash doesn’t offer this.

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Let’s take a closer look at how Flagsmith and Unleash compare when it comes to features.

Comparing Flagsmith & Unleash

Depending on what you’re looking for in your feature flagging solution, Flagsmith or Unleash might be the better choice. Here, we break down the key differences along with the benefits and drawbacks of each.

Scalability

If you’re looking for a solution that scales with ease, Unleash has some limitations. Unleash doesn’t store identities or traits, so it’s necessary to bring in the full context when evaluating flags. This has a number of drawbacks when scaling (especially for microservice architecture): 

• Real-time dependency: Every flag evaluation requires the relevant data to be provided in real time, which means that an application needs to have all user data ready at every request. This causes undue pressure and load on each transaction.
• Increased latency: Requiring the full complement of user data to evaluate feature flags can increase the latency of requests, especially in distributed systems where data might need to be fetched from various parts of the application or external services.
• Complexity in data synchronisation: Ensuring that the most up-to-date user traits are used in feature flag evaluations can be challenging. Any changes in user data need to be consistently and quickly propagated across all parts of the application to avoid discrepancies in feature flag behaviour.

As the number of users and feature flags grows, the volume of data being transmitted and processed with each request can increase significantly. This can impact the performance of both the feature flagging system and the application, particularly during peak times.

Flagsmith, on the other hand, stores identities and associated traits. This means that when flags are evaluated for an identity, the full complement of traits stored within the platform are used, even if they were not all sent as part of the request. This can be useful if your application doesn’t have all the relevant trait data available for a particular identity—the traits stored in Flagsmith will be used in addition to those passed on by your application, saving overhead.

Ease of use

If an easy set-up and a straightforward UX are important to you, Unleash may present some challenges. Their UI can be somewhat difficult to get used to and their documentation is quite heavy—especially when it comes to getting Unleash up and running. Flagsmith, on the other hand, was built with straight-up feature flagging and remote config in mind, and can be set up in less than five minutes—we’ve timed it!

Cost

Depending on your needs, Unleash can be pricier than Flagsmith. However, both solutions offer free plans. Unleash doesn’t have a free SaaS plan, though—you have to self-host. When it comes to paid plans, Unleash’s cheapest paid plan sits at $80 per month and includes two environments and three projects (for five team members). Flagsmith’s most inexpensive paid plan costs $45 per month and includes unlimited environments and projects (for three team members).

Tracking user behaviour

If you’re interested in tracking how flags affect user behaviour, Unleash has some drawbacks as they don’t have third-party analytics integrations.

How to choose between Flagsmith & Unleash

When deciding which solution to go with, it’s important to keep in mind your specific use case and needs.

If you won’t need to scale your flag usage and aren’t worried about real-time feature updates or tracking user behaviour, Unleash may be right for you. On the other hand, if being able to scale easily and securely is important and you’d like to be able to test in production for specific users, Flagsmith might make more sense. 

When it comes down to it, developers choose Flagsmith for reliability, flexibility, and cost. If these are important to you, Flagsmith might be the right fit.