
Mailgun
Resend
Twilio
Mailjet
Brevo
Amazon SES
MailChimp
Postmark is the easiest and most reliable way to be sure your important transactional emails get to the inbox. Simply & reliably parse recieved email to JSON for your webapp.

When I Work
Deputy
ResourceGuru
Float
Ganttic
Shiftee
Bizimply
Sling is a free shift scheduling and communication software. It is built around four main features - shifts, messages, newsfeed and tasks, making it possible for managers to organize all aspects of their work on a single platform.

Which is more popular?
Based on our record, Postmark should be more popular than Sling. It has been mentioned 57 times since March 2021.
Website, pricing, platforms and company facts side by side.
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| Website | postmarkapp.com | getsling.com |
| Pricing | ||
| Company | Startup from the United States | — |
| Listed in |
What each product offers, as listed by its team.


Possible disadvantages
Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
Overall verdict
Why this product is good
Recommended for
Sling is highly recommended for small to medium-sized businesses, especially those in retail, hospitality, or any sector where shift scheduling is integral. It is particularly useful for managers looking to streamline operations, enhance team communication, and improve overall staff management.
Walkthroughs and reviews on video.
Using Postmark to send email from Darkroom Booth
Sling TV 2020 Review | Is it still the best budget option?
More videos
How often each product is chosen within a category, 0–100% relative to the other.


Share your experience with using Postmark and Sling. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


Postmark are the most expensive transactional email service (10x the cost of Amazon SES), so what do they do to justify the sky high pricing? Their focus seems to be on providing a high-end service using only the best...
Sling offers a wide variety of integrated tools — everything from scheduling, time tracking, and communication to employee documents, team task management, and labor cost control — to help you streamline your...
Sling’s scheduling abilities aren’t unlike many of the other apps on this list. However, one stand-out feature is the fact that it comes with an availability tracker. That way, you can ensure that you only schedule...
Recommendations tracked on public social media and blogs since March 2021.


Postmark has been doing exactly one thing since 2010: transactional email, done carefully. It enforces a hard separation between transactional and bulk/marketing sending streams (you can't mix them on the same account), which is exactly... - Source: dev.to / 4 days ago
We want to shout out Postmark for sponsoring this challenge. Postmark's developer-focused API and reliable inbound email parsing made these innovative projects possible, allowing the community to focus on creativity rather than email... - Source: dev.to / about 1 year ago
PurifyPDF is a privacy-first PDF sanitization workflow built using n8n, Postmark, PDF.co, and Airtable. - Source: dev.to / over 1 year ago
Using Sling (https://getsling.com/) for a distributed CS team. It's working pretty well. We're spread across six timezones, been using it for five months. Free version's done well enough for us. Source: about 4 years ago
If you want to try a free product, Sling scheduling app is good. You can google the reviews to see if that match your needs. Source: over 4 years ago
But I think you might want to look at some more dedicated scheduling software like Sling. Source: over 4 years ago
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Brings voice and messaging to your web and mobile applications.
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Resource management software that helps teams schedule with clarity, plan with flexibility, and deliver projects with confidence.
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