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Ideas for the next send
Deep dives on email, developer experience, and the infrastructure behind thoughtful products. Join the waitlist for launch updates.
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Switching from Resend to Sendflit without rewriting your code
Point your Resend SDK at Sendflit’s /resend endpoint, swap the key, and keep the batch, scheduled-send and webhook calls your app already makes.
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Moving from Loops to Sendflit: contacts, lists and broadcasts
Import contacts from a Loops CSV, point your Loops integration at /loops/api/v1, and verify the move before your next broadcast.
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Resend and Loops in one account: what Sendflit combines
Transactional email, broadcasts, deliverability checks and an AI agent, with Resend and Loops compatible APIs in a single account.
What SPF, DKIM and DMARC do, and why your domain needs all three
SPF, DKIM and DMARC are DNS records that tell inbox providers which servers may send for your domain and whether the mail is authentic.
How to roll out DMARC without breaking legitimate mail
Start with a monitoring policy, read the reports, fix the senders you missed, and only then move to quarantine or reject.
Reading your domain deliverability score, point by point
Every domain is scored out of 100. Here is how the 50 setup points and 50 reputation points work, and what to fix first.
Sending email exactly once with idempotency keys
An Idempotency-Key header lets you retry a send safely. Learn how the same key and body behave, and what a 409 response means.
Batch sending: 100 emails per request, done safely
How batch sending works, how to handle partial failures, and why retries should reuse the same idempotency key.
Handling bounces and complaints with webhooks
Bounce and complaint events tell you which addresses to stop mailing. Here is how to act on them automatically.
Verifying webhook signatures before you trust a payload
Webhooks are HMAC-signed. Verify the signature against the raw request body before you update any record.
Using an SMTP relay when your app only speaks SMTP
Some frameworks and legacy apps can only send over SMTP. Here is how to point them at Sendflit safely.
API keys with full, sending and read scopes: a least-privilege setup
Give each service the smallest scope it needs, store keys in a secret manager, and revoke any key you no longer use.
Scheduled emails and how to cancel them
Send a message later with an ISO 8601 timestamp, and cancel it before it goes out if the plan changes.
Letting an AI agent draft email: what to approve and what to check
An AI agent can draft broadcasts and suggest segments. Approve only what you have reviewed, and check the audience first.
Connecting Claude to your email account with the MCP server
The MCP server lets Claude and other compatible agents use your Sendflit account, with the same scopes as any API key.
Testing subject lines before a broadcast goes out
Test up to four subject lines on a sample, then send the winner at the best time. What to measure and what to ignore.
Transactional and marketing email: keep them separate in practice
Password resets and receipts need different handling from newsletters. Separate the streams, sender names and suppression rules.
One-click unsubscribe: why link scanners should not unsubscribe your users
Unsubscribing should be a POST with a signed link, so security scanners that open links don’t remove people from your list.
Suppression lists: when to add, when to remove, and why they protect you
Suppressed addresses are blocked before sending. Here is how bounces, complaints and manual removals should feed the list.
Building email templates with React Email
Write email templates as React components, preview them locally, and send the rendered HTML through Sendflit.
Designing webhooks people trust
Predictable payloads and clear retries turn webhooks into infrastructure teams actually rely on.
Observability for outbound mail
What to log, what to alert on, and how to keep noisy signals from drowning out real incidents.
Templates that scale with your team
A component-driven approach to email templates keeps design and engineering moving in the same direction.
Build email that feels like your product
The best product email is clear, useful, and close to the code that sends it.
A practical guide to delivery events
Trace every message, inspect failures, and make delivery part of your product workflow.
From API key to production
A focused path for teams moving their first send into a dependable production system.