---
title: "Free email and SMS tools"
description: "Check SPF, DKIM and DMARC, read email headers, look up SMTP errors and count SMS segments. Free, no sign-up, and it runs in your browser."
url: https://www.unitpost.com/tools
section: "Free tools"
updated: 2026-11-04
---

# Free email and SMS tools

> Check SPF, DKIM and DMARC, read email headers, look up SMTP errors and count SMS segments. Free, no sign-up, and it runs in your browser.

HTML hub: https://www.unitpost.com/tools

- [Check your email domain's SPF, DKIM and DMARC](https://www.unitpost.com/tools/domain-checker): Check a domain's SPF, DKIM, DMARC and MX records in your browser and get a graded report that names each problem and the record that fixes it. ([Markdown](https://www.unitpost.com/tools/domain-checker.md))
- [Check your SPF record](https://www.unitpost.com/tools/spf-checker): Look up a domain's SPF record, count its DNS lookups against the limit of 10, follow every include, and see what each error means and how to fix it. ([Markdown](https://www.unitpost.com/tools/spf-checker.md))
- [Check your DMARC record](https://www.unitpost.com/tools/dmarc-checker): Look up a domain's DMARC record at _dmarc, see the policy receivers apply, check the report addresses, and get the fix for each problem found. ([Markdown](https://www.unitpost.com/tools/dmarc-checker.md))
- [Look up a DKIM record](https://www.unitpost.com/tools/dkim-checker): Look up a DKIM public key by selector and check its type, size and flags. Leave the selector empty to try common ones, and see the fix for each problem. ([Markdown](https://www.unitpost.com/tools/dkim-checker.md))
- [Generate a DMARC record](https://www.unitpost.com/tools/dmarc-generator): Build a DMARC record: pick a policy, a subdomain policy and a report address, then copy the value and publish it as a TXT record at _dmarc on your domain. ([Markdown](https://www.unitpost.com/tools/dmarc-generator.md))
- [Analyze email headers](https://www.unitpost.com/tools/email-header-analyzer): Paste a message's headers to see its SPF, DKIM and DMARC results, alignment, unsubscribe headers and the delay at each hop. Nothing leaves your browser. ([Markdown](https://www.unitpost.com/tools/email-header-analyzer.md))
- [SMTP reply and status codes](https://www.unitpost.com/tools/smtp-codes): Look up an SMTP reply such as 550 5.7.26 or 421 4.7.0: what the basic and enhanced codes mean, whether to retry, and what to fix. ([Markdown](https://www.unitpost.com/tools/smtp-codes.md))
- [SMS character and segment calculator](https://www.unitpost.com/tools/sms-segment-calculator): Count SMS characters and segments as you type: see GSM-7 or UCS-2 encoding, which characters force UCS-2, and the cost per message by country. ([Markdown](https://www.unitpost.com/tools/sms-segment-calculator.md))