Auth0 vs Postmark
Customer identity platform from Okta
vs. Reliable transactional email with fast delivery
Pricing tiers
Auth0
B2C Essentials
Starting at 500 MAUs. Pro MFA, RBAC, passwordless, SAML, 10 orgs.
$35/mo
B2B Essentials
Unlimited orgs, 3 SSO connections, RBAC.
$150/mo
B2C Professional
Starting at 500 MAUs. Includes attack protection, custom DB, enterprise MFA.
$240/mo
B2B Professional
5+ SSO connections, attack protection, custom DB.
$800/mo
Enterprise
Custom. 99.99% SLA, dedicated support.
Custom
Postmark
Free
100 emails/month forever. No credit card. Side projects and testing.
Free
Basic — 10k
10,000 emails/month. Overage $1.80/1k. Unlimited emails/day.
$15/mo
Pro — 10k
10,000 emails/month. Overage $1.30/1k. Inbound email + message streams.
$17/mo
Platform — 10k
10,000 emails/month. Overage $1.20/1k. Team collab, more domains.
$18/mo
Enterprise (>1.5M)
Custom for senders exceeding 1.5M/month.
Custom
Free-tier quotas head-to-head
Comparing b2c-essentials on Auth0 vs free on Postmark.
| Metric | Auth0 | Postmark |
|---|---|---|
| mau start | 500 MAU | — |
| sso connections | 0 conns | — |
Features
Auth0 · 14 features
- Attack Protection — Bot detection, brute-force protection, breached-password detection, suspicious I…
- Auth0 Actions — Node.js + TS hooks that run during auth flows (login, post-login, signup, MFA). …
- Auth0 FGA (OpenFGA) — Fine-grained relationship-based authorization (ReBAC). Based on Google Zanzibar.
- Custom Database — BYO user DB: scripts in Actions read from your database and create Auth0 users o…
- Custom Domain — Serve auth at auth.yourbrand.com with managed cert.
- Enterprise SSO — SAML 2.0 + OIDC + AD/LDAP enterprise connections. Per-tenant or per-org.
- Log Streaming — Stream tenant logs to Datadog, Splunk, Sumo Logic, Azure Sentinel, HTTP, Mixpane…
- Machine-to-Machine — Client-credentials grant for backend services.
- Multi-Factor Auth — SMS, Voice, Email, TOTP, WebAuthn (biometrics), Push (Guardian app), Duo.
- Organizations — Multi-tenant B2B: orgs with invitations, roles, branding, enterprise connections…
- Passkeys — FIDO2/WebAuthn passkey sign-in.
- Passwordless — Email magic link + code, SMS code, WebAuthn.
- RBAC — Roles, permissions, API scopes — attach to users or orgs.
- Universal Login — Hosted login page with customization, multi-factor flows, passwordless, social, …
Postmark · 12 features
- Activity Search — Full-text search over sent messages for 45-365 days.
- Bounce Handling — Automatic hard/soft bounce detection + suppression management.
- Broadcast Messages — Via separate Broadcast Message Stream. Bulk sends with throttling.
- DKIM + SPF — One-click verification + auto-renewal of DKIM keys.
- Inbound Email — Route inbound emails to your webhook. Parse attachments, threads.
- Message Streams — Isolate transactional from marketing for separate deliverability reputation.
- Open + Click Tracking — Configurable at template or send level.
- Raw API Access — 100+ endpoints for bounces, servers, tags, templates, stats.
- Servers — Multi-tenant isolation: each "server" has its own API token + reputation.
- Templates — Mustachio template language with variables, alias + versioning.
- Transactional Send — Reliable API for password resets, receipts, notifications. Sub-10s delivery.
- Webhook Events — Delivery, bounce, spam complaint, open, click, subscription change.
Developer interfaces
| Kind | Auth0 | Postmark |
|---|---|---|
| CLI | Auth0 CLI | — |
| SDK | Auth0 Android, Auth0 iOS/Swift, @auth0/nextjs-auth0, Auth0 React SDK, Auth0 SPA.js SDK, Go Auth0 SDK, Node Auth0 Backend SDK, Python Auth0 SDK | postmark-dotnet, postmarker (Python), postmark-go, postmark (Node), postmark-php, postmark-rails |
| REST | Authentication API, Management API | Postmark REST API |
| OTHER | — | Inbound Email, SMTP Relay, Webhooks |
Staxly is an independent catalog of developer platforms. Outbound links to Auth0 and Postmark are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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