Authentication Providers - Notes

• Authentication Providers
• Notes

A brief list of authentication providers.

ℹ️ This is a "notes collection" item. I use notes collection to compile practical information for myself in an unpolished way. It's probably best not to rely on this information without verifying it against up-to-date sources. Also, it is not a good place to use as reference, as the content is subject to frequent updates without warning.

Intro

These notes are useful if you’re looking for a free (or not too expensive) authentication provider for your side project. If you’re looking for a business solution, please dig deeper for the necessary compliance requirements for your business, such as HIPAA, GDPR, SOC 2, etc.

Authentication is expensive, both in terms of development and actual costs. Most authentication providers offer free tiers; however, if your product somehow scales up, you might be in for a big surprise. :) Here, I’ll try to normalize the cost required to serve 1K users in a real-world environment as of today. (May 2025)

• I’ll use the next plan available after the free tier for each provider for the comparison.
• This is a note I’ve taken to get a relative overview of authentication provider pricing.
• I collected the information from the official pricing pages of the providers in May 2025, based on their monthly offers. Please refer to the respective pages for up-to-date pricing.
• Features like custom domains, business-to-business authentication, single sign-on, etc., might have custom pricing. The numbers below are mostly for basic features only.
• All providers count users only if they are active. Check their documentation for the definition of MAU (Monthly Active Users).

Authentication-only

1. https://auth0.com/pricing
   1. Basic Paid Tier: 70$ / 1K users
   2. Free Tier: 25K users
   3. Monthly Cost per 1K Users: 70$
   4. B2C use case. Probably the most production ready provider for a wide range of domains.
2. https://workos.com/pricing
   1. Basic Paid Tier: 2500$ / 1M users
   2. Free Tier: 1M users (Only on a staging environment.)
   3. Monthly Cost per 1K Users: Not Applicable / ~2.5$
   4. Actual pricing is scaled for 1M (million) users. I’m not sure if there is an option for fewer users.
3. https://clerk.com/pricing
   1. Basic Paid Tier: 20$ / 1K + 25$ monthly subscription.
   2. Free Tier: 10K users
   3. Monthly Cost per 1K Users: 45$
   4. Seamless integration with Next.js App Router.
4. https://stack-auth.com/pricing
   1. Basic Paid Tier: 49$ / 50K users
   2. Free Tier: 10K users
   3. Monthly Cost per 1K Users: Not Applicable / ~0.98$
   4. No per-user pricing, 49$ monthly subscription for 50K users.
   5. Open source self-host option is offered.
   6. Seamless integration with Next.js App Router.
5. https://stytch.com/pricing?vertical=b2c
   1. Basic Paid Tier: 200$ / 1K
   2. Free Tier: 10K users
   3. Monthly Cost per 1K Users: 200$

BaaS with Authentication

1. https://supabase.com/pricing
   1. Basic Paid Tier: 3.25$ / 1K users + 25$ monthly subscription.
   2. Free Tier: 50K users
   3. Monthly Cost per 1K Users: 28.25$
   4. Build on top of Netlify’s GoTrue. (Netlify is not maintaining an Identity service or a library anymore.)
   5. Paid tier adds 50K more users to free tier and starts after 100K users.
   6. Since this is a BaaS product, you’ll get access to all paid features with the paid subscription.
2. https://appwrite.io/pricing
   1. Basic Paid Tier: 3$ / 1K users + 15$ monthly subscription.
   2. Free Tier: 75K users
   3. Monthly Cost per 1K Users: 18$
   4. Paid tier adds 125K more users to free tier and starts after 200K users.
   5. Since this is a BaaS product, you’ll get access to all paid features with the paid subscription.
3. https://neon.tech/pricing
   1. Offers an authentication solution in beta; no pricing details have been disclosed.
   2. Based on Stack Auth.
4. https://firebase.google.com/pricing
   1. Basic Paid Tier: 5.5$ / 1K users
   2. Free Tier: 50K users
   3. Monthly Cost per 1K Users: 5.5$
   4. Pricing re-adjusts on user count. More users = lower cost. Each tier applies a reduced rate for users within that tier. See their pricing page for details. The numbers above apply to up to 100K users.
5. https://aws.amazon.com/cognito/pricing/
   1. Basic Paid Tier: 5.5$ / 1K users
   2. Free Tier: 10K users
   3. Monthly Cost per 1K Users: 5.5$
   4. The estimations are for the “Lite Tier”. Cognito also offers an “Essentials Tier” with more login options. The numbers above apply to up to 100K users on the “Lite Tier”. More users = lower cost is also applies to this provider.
   5. The “Lite Tier” offers only password-based methods.
   6. Separate charges apply for email messages.
6. https://www.cloudflare.com/en-gb/plans/zero-trust-services/
   1. Cloudflare doesn’t offer a consumer identity solution; however, if you’re looking for an access solution for your staging environments on Cloudflare products, “Cloudflare Zero Trust / Access” can help.
   2. Limited to 50 users on the free tier.

JavaScript Libraries

1. https://authjs.dev/
   1. Free and open-source, with welcoming documentation, framework support, and backed by major authentication providers.
   2. ISC License
2. https://stack-auth.com/
   1. Open-source, per package licensing.
   2. MIT License (Client Libraries)
   3. AGPLv3 License (Server Components) — permissive, but derivative works must also be licensed under the same terms.
3. https://www.better-auth.com/
   1. Open source, multi-framework, multi-method implementation.
   2. MIT License
4. https://lucia-auth.com/
   1. No longer a maintained library, but still a great learning resource.
   2. Deprecated as of March 2025.
   3. MIT License (Library) + 0BSD (Site, code examples.)