Resend vs Flagsmith
The email API for developers — built by the Nodemailer team
vs. Open-source feature flags + remote config — SaaS, private cloud, self-host
Pricing tiers
Resend
Free
3,000 emails/month, 100 emails/day. 1 custom domain. Ideal for side projects.
Free
Pro — 50k
50,000 emails/month. 10 custom domains. Priority support.
$20/mo
Pro — 100k
100,000 emails/month. 10 custom domains.
$35/mo
Scale — 100k+
Tiered from 100k → 2.5M emails/month. Dedicated IP add-on available.
$90/mo
Scale — 2.5M
2.5M emails/month.
$1150/mo
Enterprise
3M+/month, dedicated IP included, SSO, custom contract.
Custom
Flagsmith
Free
$0. 50,000 API requests/mo. 1 team member. Unlimited flags. Community support.
Free
Self-hosted
$0 (OSS). Host yourself via Docker/K8s. Fair-source license (non-compete).
$0 base (usage-based)
Start-up
$40/mo. 1,000,000 API requests/mo. 3 team members. Standard support.
$40/mo
Scale-up
$200/mo. 5,000,000 API requests. 10 team members. Priority support + SLA.
$200/mo
Enterprise
Custom. Unlimited API requests, SSO, SAML, RBAC, audit logs, on-prem.
Custom
Free-tier quotas head-to-head
Comparing free on Resend vs free on Flagsmith.
| Metric | Resend | Flagsmith |
|---|---|---|
| custom domains | 1 domains | — |
| emails per day | 100 emails/day | — |
| emails per month | 3000 emails/month | — |
Features
Resend · 12 features
- Audiences — Contact list management with custom fields.
- Batch Send — Send up to 100 emails in one API call.
- Broadcasts — Bulk email campaigns with audiences, A/B testing, analytics.
- Dedicated IP — Add-on for high-volume senders. Auto warmup.
- Domains — DKIM/SPF/DMARC auto-verification. Per-domain analytics.
- Idempotency — Prevent duplicate sends with Idempotency-Key header.
- Logs + Analytics — Full email logs, delivery heatmap, events table.
- React Email — OSS library (3M+ downloads) to compose emails in React/JSX.
- Scheduled Send — scheduledAt parameter for future delivery.
- Send API — POST /emails endpoint to send. Supports attachments, scheduled send, idempotency…
- Suppressions — Auto-managed bounce + complaint list. API to add/remove.
- Webhooks — Email lifecycle events: sent, delivered, bounced, complained, opened, clicked.
Flagsmith · 14 features
- A/B Testing — Multivariate flag splits.
- Audit Log — Full history of flag changes.
- Change Requests — Approval workflow for flag changes.
- Edge API — Global low-latency flag eval.
- Feature Flags — Boolean + multivariate + JSON flags.
- Local Evaluation — Server SDKs eval flags locally — no per-req API call.
- Percentage Rollouts — Gradual traffic ramp.
- Remote Config — Non-boolean config values.
- Role-Based Access — Fine-grained permissions.
- Scheduled Flags — Time-based flag changes.
- Segments — Rule-based targeting.
- Self-Hosting — Docker/Helm install.
- SSO + SAML — Enterprise SSO.
- Webhooks — Outbound event streaming.
Developer interfaces
| Kind | Resend | Flagsmith |
|---|---|---|
| CLI | Resend CLI | Flagsmith CLI |
| SDK | react-email, resend-go, resend-node, resend-php, resend-python, resend-ruby | flagsmith-android, flagsmith-go, flagsmith-ios, flagsmith-java, flagsmith-js (browser), flagsmith-nodejs, flagsmith-python, flagsmith-ruby |
| REST | Resend REST API | Flagsmith REST API |
| OTHER | SMTP Relay, Webhooks (Svix) | Flagsmith Dashboard, Flagsmith Webhooks |
Staxly is an independent catalog of developer platforms. Some links to Resend and Flagsmith may be affiliate links — Staxly may earn a commission if you sign up through them, at no extra cost to you. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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