Postmark vs Kinde
Reliable transactional email with fast delivery
vs. Flexible authentication, user management, and feature flags
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
Kinde
Free
10,500 MAU included. MFA, B2B orgs, custom domain, 2 custom roles, 1 webhook, 2 environments.
Free
Pro
Unlimited webhooks, roles, feature flags, API keys. Remove Kinde branding. SOC 2 attestation.
$25/mo
Plus
Unlimited enterprise SSO, API scopes, org-owned M2M apps, 6 environments.
$75/mo
Scale
11 environments, custom domain per org, SCIM, MFA triggers, 30-day audit logs.
$250/mo
Enterprise
Custom. Dedicated infra option, volume discounts, custom SLAs.
Custom
Free-tier quotas head-to-head
Comparing free on Postmark vs free on Kinde.
| Metric | Postmark | Kinde |
|---|---|---|
| custom roles | — | 2 roles |
| environments | — | 2 envs |
| feature flags | — | 10 flags |
| mau included | — | 10500 users/month |
| webhooks | — | 1 webhooks |
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.
Kinde · 14 features
- API Scopes — OAuth scopes for your APIs, enforced server-side (Plus+).
- B2B Organizations — Multi-tenant orgs with user roles, invitations, feature flags per org.
- Custom Domain — Host auth at auth.yourbrand.com. Free tier includes this.
- Enterprise SSO — SAML 2.0 + OIDC enterprise connections (Plus unlimited).
- Feature Flags — Built-in feature flags with per-user/org overrides. No separate service needed.
- Kinde AI — AI-assisted query and insights over your Kinde data.
- Kinde Billing (preview) — Built-in subscription billing linked to users/orgs. Stripe under the hood.
- Machine-to-Machine — Client credentials grant for service-to-service auth.
- Multi-Factor Auth — TOTP authenticator apps, SMS, email, passkey.
- Passwordless — Email code + passkey (WebAuthn).
- Roles & Permissions — RBAC with roles → permissions. Assigned per user or per organization.
- SCIM Provisioning — Directory provisioning from IdPs (Scale tier).
- Sign-in Widget — Hosted pages + themeable widget for login/signup. Customizable with CSS.
- Webhooks — Event webhooks: user.created/updated, organization events, MFA, etc.
Developer interfaces
| Kind | Postmark | Kinde |
|---|---|---|
| SDK | postmark-dotnet, postmarker (Python), postmark-go, postmark (Node), postmark-php, postmark-rails | Kinde Android / Kotlin, Kinde Flutter SDK, Kinde Go SDK, Kinde iOS / Swift, @kinde-oss/kinde-auth-nextjs, @kinde-oss/kinde-auth-react, @kinde-oss/kinde-nodejs-sdk, Kinde Python SDK |
| REST | Postmark REST API | Kinde Management API |
| MCP | — | Kinde MCP |
| OTHER | Inbound Email, SMTP Relay, Webhooks | — |
Staxly is an independent catalog of developer platforms. Outbound links to Postmark and Kinde are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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