Postmark vs Auth0
Reliable transactional email with fast delivery
vs. Customer identity platform from Okta
Pricing tiers
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
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
Free-tier quotas head-to-head
Comparing free on Postmark vs b2c-essentials on Auth0.
| Metric | Postmark | Auth0 |
|---|---|---|
| mau start | — | 500 MAU |
| sso connections | — | 0 conns |
Features
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.
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, …
Developer interfaces
| Kind | Postmark | Auth0 |
|---|---|---|
| CLI | — | Auth0 CLI |
| SDK | postmark-dotnet, postmarker (Python), postmark-go, postmark (Node), postmark-php, postmark-rails | 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 |
| REST | Postmark REST API | Authentication API, Management API |
| OTHER | Inbound Email, SMTP Relay, Webhooks | — |
Staxly is an independent catalog of developer platforms. Outbound links to Postmark and Auth0 are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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