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For most product teams, Clerk is the easiest place to start: it combines a free tier, built-in organization controls and auth UI components, with listed pricing from $20. If your product needs enterprise SSO, compare WorkOS; if you want open-source auth, consider Logto. The rest are more specialized or harder to price from the information available. We ranked these APIs for broad product fit and value, not raw capability alone. Before switching, check where free usage ends, which features cost extra, and whether pricing is public.
Quick picksThe shortlist
ClerkClerkBest overall · $20/mo
WorkOSWorkOSBest for B2B SSO · $65/mo
LogtoLogtoBest open-source option · $24/mo
StytchStytchBest flexible identity · Free
FusionAuthFusionAuthBest self-hosted option · $162/mo
DescopeDescopeBest for custom journeys · $249/mo
Ory NetworkOry NetworkBest managed IAM · $64.17/mo
Twilio VerifyTwilio VerifyBest for OTP · $0.05/mo
PrivyPrivyBest for wallet auth · $299/mo
ProveProveBest for identity checks · Custom
DeepvueDeepvueBest for India verification · Custom
TruliooTruliooBest for broad verification · Custom
01Compared at a glance
| Tool | Score | From | Free plan | Trial |
|---|---|---|---|---|
| ClerkClerk | 7.8 | $20/mo | Yes | — |
| WorkOSWorkOS | 7.3 | $65/mo | Yes | — |
| LogtoLogto | 7.5 | $24/mo | Yes | — |
| StytchStytch | 7.6 | Free | Yes | — |
| FusionAuthFusionAuth | 7.7 | $162/mo | Yes | — |
| DescopeDescope | 7.6 | $249/mo | Yes | — |
| Ory NetworkOry Network | 6.7 | $64.17/mo | Yes | — |
| Twilio VerifyTwilio Verify | 6.5 | $0.05/mo | Yes | — |
| PrivyPrivy | 6.4 | $299/mo | Yes | — |
| ProveProve | 6.0 | Custom | No | — |
| DeepvueDeepvue | 6.2 | Custom | No | Yes |
| TruliooTrulioo | 6.0 | Custom | No | — |
02The picks, in detail
- Best overallClerkClerk
Clerk ranks first for teams that want a broad app-auth toolkit rather than a single verification method. The listing highlights multi-tenant apps, organization controls and auth UI components, plus a free plan and pricing from $20. That combination makes it the clearest starting point for many SaaS teams. Model costs as usage grows; the free tier is generous, not a reason to skip forecasting.
What works
- Free Hobby plan includes unlimited applications.
- Hobby and Pro include 50,000 MRUs per app.
- Pro includes MFA and custom session lifetime.
What doesn't
- MRU overages start at $0.02 each.
- Extra SSO or Directory Sync connections cost more.
- Business costs $300 monthly or $250 per month annually.
- Best for B2B SSOWorkOSWorkOS
WorkOS is a strong pick for B2B apps that need enterprise SSO or directory syncing, and its free authentication tier makes it worth comparing early. The listed starting price is $65, but the comparison flags per-connection SSO and Directory Sync as costs to budget for. Choose it for those enterprise needs, not as a default assumption that every feature is included.
What works
- AuthKit includes up to 1 million monthly active users free
- Supports SAML and OIDC identity providers
- Directory Sync covers SCIM and HRIS integrations
What doesn't
- SSO and Directory Sync charge per connection
- The first 15 connections cost $125 each per month
- Additional AuthKit users cost $2,500 monthly per million
- Best open-source optionLogtoLogto
Logto suits teams looking for open-source authentication with OIDC or SAML support. Its listed starting price is $24, and a free tier gives projects a lower-cost way to begin. The catch is add-on pricing: the comparison recommends pricing those extras before committing. It is a flexible Auth0 alternative, but the headline starting price is not the whole cost picture.
What works
- Open-source option with cloud and self-hosting
- Free plan allows up to 50,000 MAU
- Supports OAuth 2.1, OIDC, and SAML
What doesn't
- Pro includes only 50,000 tokens
- Extra tokens cost $0.08 per 100
- MFA, RBAC, and SSO have separate listed prices
- Best flexible identityStytchStytch
Stytch covers B2B authentication, multi-tenant identity and agent identity controls, making it a fit for products with more than a basic login requirement. The listing includes a free plan, but gives no starting paid price. Check whether its B2C or B2B offering fits your use case and get custom costs before treating the free tier as a reliable budget estimate.
What works
- $0 plan includes 10,000 monthly active users and AI agents
- Unlimited organizations on the Pay as you go plan
- Supports passkeys, SAML SSO, and OIDC SSO
What doesn't
- Extra SSO or SCIM connections cost $125 each
- Extra monthly active user and M2M token rates are not published
- Enterprise pricing is custom
- Best self-hosted optionFusionAuthFusionAuth
FusionAuth is aimed at teams that need self-hosted identity, B2B or multi-tenant identity, and API-based authentication and authorization. The listing includes a free tier and a starting price of $162, with annual-only listed pricing. Check hosted-plan caps before choosing that route. Its flexibility is appealing, but the listed price and hosting limits deserve a close read.
What works
- Free self-hosted Community plan lists unlimited MAUs
- Supports passkeys, magic links, social logins, and MFA
- Offers fine-grained authorization and role-based access control
What doesn't
- Starter's $162 monthly price requires annual billing
- Standalone month-to-month prices are not published
- Starter includes one connector and 100 machine-to-machine entities
- Best for custom journeysDescopeDescope
Descope fits teams building custom authentication journeys, multi-tenant SaaS identity or identity for AI agents. It has a free plan, but Pro starts at $249 per month with annual billing, according to the listing. That is a meaningful step up from free, so confirm the paid features you need justify the cost before making it your default choice.
What works
- Free Forever includes 7,500 MAUs and 10 active tenants.
- Visual workflows cover signup, login, MFA, SSO, and step-up journeys.
- Supports passkeys, magic links, social login, OTPs, and biometrics.
What doesn't
- Pro starts at $249 per month and is billed annually.
- Pro includes 10,000 MAUs and 35 active tenants.
- Pro and Growth monthly-billing rates are not published.
- Best managed IAMOry NetworkOry Network
Ory Network covers managed cloud IAM, customer and B2B identity, plus AI-agent and machine-to-machine access. The listed starting price is $64.17 and there is a free plan, but the free plan cannot run production. Paid usage is metered, so estimate likely use before switching; the starting price alone will not tell you what a production setup costs.
What works
- Managed IAM without self-managing infrastructure
- Customer, B2B, and agent identity
- Authentication, authorization, and permissions
What doesn't
- Developer plan has zero production environments
- Production costs $770 yearly, billed annually
- Monthly prices are not published
- Best for OTPTwilio VerifyTwilio Verify
Twilio Verify is the focused choice here for pay-as-you-go one-time passcodes and account verification. The listing gives a free plan and a price from $0.05 per verification, which is easier to assess than custom-priced alternatives. The comparison also flags reported delivery and fallback wrinkles, so weigh those concerns against the simple per-verification starting price.
What works
- Starts at $0.05 per verification
- Free trial listed; no credit card required
- Volume discounts as usage scales
What doesn't
- Monthly and annual billing are not specified
- WhatsApp SMS fallback may need extra setup
- A Reddit user reports international delivery delays
- Best for wallet authPrivyPrivy
Privy is best suited to products embedding digital-asset wallets, adding programmable transaction controls or connecting cards to wallet balances. The listing shows a free plan and pricing from $299, but warns that costs rise quickly beyond included usage limits. That makes Privy a specialized pick: check expected usage and wallet requirements before comparing it with general-purpose authentication tools.
What works
- Free plan includes core wallet features
- Wallets support both users and autonomous agents
- Policy engine supports rules, approvals and transfer controls
What doesn't
- Core starts at $299 per month
- Core and Scale both list 50,000 monthly signatures
- Core and Scale both list $1 million monthly transaction volume
- Best for identity checksProveProve
Prove is positioned for identity checks inside products, verification of people and businesses, and securing AI-agent transactions. Its starting price is not listed, and the comparison describes its custom pricing as opaque. That makes cost comparison difficult before a sales conversation. Consider it when those identity and authentication use cases match your product, but ask for pricing and scope up front.
What works
- Covers identity verification and authentication APIs
- Supports people, businesses, and AI agents
- Offers identity pre-fill with optional KYC checks
What doesn't
- No published starting price
- No free plan or trial listed
- Monthly and annual billing details are unpublished
- Best for India verificationDeepvueDeepvue
Deepvue is a niche fit for India-focused fintech verification, teams needing several check types and variable volumes that suit prepaid checks. The listing provides no starting price and says pricing and technical details need to be pinned down. That makes it harder to assess against more transparent tools. Confirm both the technical requirements and the cost structure before planning a switch.
What works
- DigiLocker-based Aadhaar identity verification
- Face matching and passive liveness checks
- Bank ownership checks and IFSC validation
What doesn't
- Rates vary by check type
- High Volume pricing requires a custom quote
- Trial duration isn't published
- Best for broad verificationTruliooTrulioo
Trulioo covers person and business checks, AML screening and assessment of AI-agent credentials. The listing gives no public rates or limits, so buyers cannot compare its cost from published pricing alone. Some users report verification-related delays, another point to investigate for workflows where timing matters. It may fit broad verification needs, but request pricing and clarify service expectations first.
What works
- Covers identity documents, biometrics and supported digital IDs
- Verifies business information, ownership and associated people
- Assesses email, phone, IP, device and behavioral signals
What doesn't
- No public monthly or annual rates
- Usage and seat limits are not published
- Pricing requires a custom sales quote
03How we chose
We weigh published pricing, stated plan limits, documentation, and Reddit sentiment when comparing authentication and identity APIs. We look for clear details about what a plan includes, where limits apply, and what the docs explain about integration and account management. When a vendor does not publish a price or cap, we treat it as undisclosed rather than estimate it. Reddit comments are user reports, not verified product specifications. We do not claim hands-on testing, benchmarks, or trial results; the comparison is based on available published material and attributed user feedback.
04Choose the API for the identity job you need done
Start with the task, not the vendor’s feature list. Decide whether you need to add application login, verify a user’s identity, confirm control of a phone number, or manage authentication across an existing product. Those jobs can overlap, but they are not interchangeable. Write down the user flow you need, including what happens when verification fails or a user loses access.
Then check the docs for the flow you plan to build. Look for stated integration steps, supported methods, and any limits or prerequisites. If a capability is not described in the material you can find, ask the vendor rather than assuming it is included. For a shortlist spanning Privy, Prove, WorkOS, Clerk, Twilio Verify, Ory Network, Stytch, Descope, Deepvue, Logto, FusionAuth, and Trulioo, compare each against the same requirements. A name on a shortlist is not proof of fit.
05Compare the real cost and switching work
Do not compare only the lowest advertised price. Check what the pricing page says is included, which plan limits apply, and whether the price or cap is unpublished. Estimate usage against your expected sign-ins or verification needs, but do not treat an estimate as a vendor quote. Ask about overages and pricing for the specific features your application requires if the public details leave gaps.
For a switch, list the identity data and user flows you would need to move or rebuild. Review the docs for available integration guidance, and ask vendors how they handle the parts the docs do not cover. Plan for changes to sign-in, recovery, and verification flows, and decide how you will validate them before rollout. Reddit reports can flag questions worth asking, but they are anecdotal and should not replace current pricing or written vendor answers. Keep a record of what is confirmed and what remains unknown.
Questions people ask
How should we compare authentication API pricing?
Compare the published price alongside its stated plan limits and included features. Match those details to your expected usage, and mark anything missing as unpublished rather than guessing. If overages or required capabilities are unclear, request written pricing for your use case before choosing.
Are login and identity verification APIs interchangeable?
Not necessarily. Login, authentication, phone verification, and identity checks describe different jobs, even when a product may cover more than one. Define the user flow you need, then confirm in the vendor’s docs or written response that the specific capability and limits fit.
What should we check before switching identity providers?
Map the existing sign-in, recovery, and verification flows, then identify the user information and integrations involved. Review the new provider’s docs and ask about anything they do not address. Confirm migration requirements and rollout steps with the vendor rather than assuming accounts will transfer unchanged.
How much weight should we give Reddit reviews?
Treat Reddit comments as anecdotal reports that can point to questions about pricing, support, or implementation. They are not a substitute for current product documentation or a written vendor answer. Check whether a reported issue applies to the plan and use case you are considering.