Thirteen services that all send a JSON email call, compared on the same ten criteria with the vendor’s own numbers and the date they were read. Notix is one of the thirteen and we build it, so the page says plainly where each of the others is the better choice.
Every email API can deliver a receipt. The differences are in what happens around that call, and those are the things that cost engineering time later.
A flat monthly plan with an included allowance, per-thousand metering with no minimum, or a trial that ends. Ask what the bill is at 10,000, 50,000 and 100,000 emails a month, and whether the free tier has an end date or asks for a card.
SMTP means a framework mailer works unchanged. An SDK in your language saves an afternoon; a plain HTTP endpoint works anyway. Webhooks decide whether delivery status arrives on its own or you poll for it.
Who keeps the list of addresses you must never mail again, and does it cover marketing too? Is there an API for one-time codes, or do you build expiry and attempts yourself? Can you check a message before sending it?
Almost every service bills in US dollars by card. If your team pays from Nigeria or Kenya, that is a real constraint, not a footnote.
A published commitment with credits is different from a marketing sentence. Look for the percentage, the plans it applies to and what you get back when it is missed.
Notix is the last column. Each vendor’s figures come from its own pricing page; the footer says when it was read.
| Criterion | Resend | SendGrid | Postmark | Mailgun | Amazon SES | MailerSend | Brevo | Courier | Customer.io | Loops | Mailchimp Transactional (Mandrill) | SparkPost (Bird) | Notix |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Free tier | 3,000 emails a month, 100 a day, 1 domain | 60-day trial, 100 a day; sending stops when the trial ends (the free plan was retired from 27 May 2025) | 100 emails a month on the developer plan | 100 emails a day, one inbound route | $200 in AWS Free Tier credits for new accounts, valid for 6 months; new accounts start in a sandbox | 500 emails a month, 1 domain, 100 API requests a day, 1 webhook, 1 template | 300 emails a day once the account is approved for sending; API, SMTP and webhooks on every plan | Developer plan: 10,000 sends a month | No free plan; a free year for startups that have raised under $10M | 1,000 subscribed contacts and 4,000 emails in any 30-day window, marketing and transactional together, with Loops branding | Up to 500 free sends to a verified domain; needs a Mailchimp Standard or Premium plan | 1,000 emails a month, no card, no time limit | 5,000 emails a month, 200 a day, no card, no end date |
| Entry paid plan | Pro $20 a month | Essentials from $19.95 a month | Basic $15 a month | Basic $15 a month | Pay as you go, $0.10 per 1,000 emails à la carte | Hobby $5.60 a month billed yearly ($67.20 a year); $7 month to month | Starter $9 a month, $8 on the yearly plan | Business: $0.005 per send, no per-seat or channel fees | Essentials: price not shown on the pricing page | Priced by subscribed contacts; tier prices not shown on the pricing page | $20 per block of 25,000 emails (1 to 20 blocks), on top of a Mailchimp plan | Startup from $15 a month | Pro $15 a month |
| Included on that plan | 50,000 emails a month | 50,000 to 100,000 emails a month on Essentials, volume-priced | 10,000 emails a month, then $1.80 per extra 1,000 | 10,000 emails a month (Foundation: $35 for 50,000) | None: $0.16 per 1,000 on the Essentials plan, $0.12 per GB of attachments | 5,000 emails a month, then $1.50 per extra 1,000 (Starter: 50,000 for $35, $0.90 per extra 1,000) | From 5,000 emails a month (Standard: $18 a month, $16 yearly; Professional from 150,000 emails at $449 yearly) | None included; usage-based per send, volume discounts on Enterprise | Essentials: 5,000 profiles and 1 million emails a month; extra emails $0.12 per 1,000 | Unlimited sends on paid plans, up to 1,000 emails a second per team | 25,000 emails per block; $18 a block from 21 blocks, down to $10 a block past 160; dedicated IP $29.95 a month | 50,000 to 100,000 emails a month on Startup; Growth from $80 for 100,000 to 2.5 million; overage $0.90 per 1,000 | 50,000 emails, usage past that metered on the same invoice |
| SMTP relay | Yes, on every plan | Yes | Yes, on every plan | Yes, on every plan | Yes, an SMTP interface and an API | Yes, on every plan including Free | Yes, on every plan including Free | Not stated in the docs index | Custom SMTP on some plans; transactional sends go through the API | No; transactional email is API only | Yes | Yes | Yes, on every plan |
| SDKs | Node, Python, PHP, Ruby, Go, Java, Laravel, Rust, .NET | Node, Python, PHP, Ruby, Go, Java, C# | Node, Python, Ruby, PHP, .NET, and a documented cURL surface | Node, Python, PHP, Ruby, Go, Java, C# | Every AWS SDK language | Node, PHP, Laravel, Python, Ruby, Go, Java | Node, Python, PHP | Node, Python, Go, Ruby, Java, PHP, C# (server); React, JavaScript, iOS, Android, React Native, Flutter (client) | Mobile SDKs for iOS, Android, React Native, Expo and Flutter; server languages not listed | JavaScript/TypeScript, Go, PHP, Ruby | PHP, Node, Python, Ruby | PHP, Node, Python, Go | TypeScript, Python, Go, PHP |
| Webhooks | Yes | Yes | Yes | Yes | Through SNS event destinations, which you wire yourself | Yes, HMAC-SHA256 signed; 1 on Free and Hobby, 50 on Starter | Yes; the docs recommend an IP allowlist rather than a signature | Not stated in the docs index | Yes, reporting webhooks | Not stated in the API docs | Yes | Yes | Yes, signed, for email, contact and domain events |
| OTP / verification API | No | No | No | No | No | No | No | No | No | No | No | No | Yes, email and SMS codes |
| Deliverability check before sending | No | Email validation API on Pro and above | No | Email validation as an add-on ($1.80 per 1,000 on Basic; 5,000 included from Foundation) | No | Email address verification as an add-on ($0.01 per address for the first 5,000; 10 credits on Free) | No | No | No | No | No | Recipient Validation API; price not stated on the pricing page | Yes, a pre-send check API |
| Billing outside USD | USD by card | USD by card | USD by card | USD by card | USD, on the AWS bill | USD by card (EUR and GBP shown for information only) | By card through Adyen, or PayPal | Not stated on the pricing page | USD | Not stated on the pricing page | Not stated on the pricing page | USD | USD by card; naira and shillings from a prepaid wallet |
| SLA | Not stated on the pricing page | Stated for Pro and Premier plans | Not stated on the pricing page | Stated for Scale and above | AWS SES service level agreement | 99.5% on Professional and above | Not stated on the pricing page | Enterprise SLA on the Enterprise plan | Not stated on the pricing page | Not stated on the pricing page | Not stated on the pricing page | Not stated on the pricing page | 99.9% on Pro, credits on the pricing page |
| Prices and limits read from the vendors' own pages: resend.com on 2026-09-12; www.twilio.com on 2026-09-13; postmarkapp.com on 2026-09-13; www.mailgun.com on 2026-09-13; aws.amazon.com on 2026-09-13; www.mailersend.com on 2026-09-13; www.brevo.com on 2026-09-13; www.courier.com on 2026-09-13; customer.io on 2026-09-13; loops.so on 2026-09-13; mailchimp.com on 2026-09-13; bird.com on 2026-09-13. Notix figures are from its own pricing page. | |||||||||||||
The developer-experience choice for React and Next.js teams. 3,000 emails a month, 100 a day, 1 domain; Pro is $20 a month for 50,000 emails a month. Nine SDKs and React Email are its strongest points, and it has no OTP API or pre-send check. Read Notix vs Resend or the Resend alternative page.
Enterprise scale under Twilio. 60-day trial, 100 a day; sending stops when the trial ends (the free plan was retired from 27 May 2025). Paid plans start with Essentials from $19.95 a month, Pro adds dedicated IPs, and Marketing Campaigns is a separate product. Right for high volume with a contract; wrong if you wanted a free tier that stays. Read Notix vs SendGrid or the SendGrid alternative page.
Transactional-only, on infrastructure it owns and a reputation it publishes. 100 emails a month on the developer plan; Basic $15 a month for 10,000 emails a month, then $1.80 per extra 1,000. If deliverability is the one thing you will pay for, it is the honest pick; the included volume is the lowest here. Read Notix vs Postmark or the Postmark alternative page.
A developer email API with inbound routing and an email validation product, now part of Sinch. 100 emails a day, one inbound route; Basic $15 a month for 10,000 emails a month (Foundation: $35 for 50,000). The choice when you need to receive and parse mail, not only send it. Read Notix vs Mailgun or the Mailgun alternative page.
The cheapest per email by a wide margin: Pay as you go, $0.10 per 1,000 emails à la carte, with $200 in aws free tier credits for new accounts, valid for 6 months; new accounts start in a sandbox. What it does not include is everything else: a dashboard, a suppression list across products, templates, webhooks you do not wire through SNS yourself. Right for AWS-native teams with the time to build that layer. Read Notix vs Amazon SES, the SES alternative page, or whether to use SES directly at all.
Transactional and marketing email in one account with one suppression list, plus an OTP and verification API, a pre-send deliverability check, an SMTP relay, signed webhooks and four SDKs. 5,000 emails a month free with no card and no end date; Pro is $15 a month for 50,000, with usage past that metered on the same invoice, payable by card or from a naira or shilling wallet, with a 99.9% SLA on Pro. What it does not have: nine SDKs, inbound routing, dedicated IPs or SES’s per-thousand price. See pricing and the transactional email API.
Asked plainly, “what is the best transactional email API for a startup” has no single answer, because startups do not share a constraint. The useful version of the question is “which one removes the work I would otherwise do”, and that has a short mapping.
Whichever you pick, put the sending call behind one function in your codebase. Every service in the table takes a from, a to, a subject and a body; moving between them is a one-file change when the call is not scattered across the app.
Eight short sections each, ending with a “choose X if” list. The alternatives pages cover the migration; the docs cover the calls.
Pricing, sending API, deliverability tooling, SDKs and billing regions, side by side with a read date.
What changes when you leave a 60-day trial for a free plan that stays, and where SendGrid's scale still wins.
Ten thousand emails for $15 against fifty thousand, and the one thing Postmark has that Notix does not claim.
Same $15 entry, different included volume, and where Mailgun's inbound routing and validation matter.
Per-thousand pricing against a flat plan, and what SES leaves you to build before the first receipt goes out.
Free tiers, per-email pricing, the sending API, deliverability tooling and billing regions, side by side with a read date.
A marketing suite with a transactional API against a developer email API, on price, sending, deliverability and billing regions.
The two services on free tier, price, sending API, deliverability tooling and SLA, read from their own pages, with Notix in a separate third column.
Two developer-first email APIs compared on free tier, price per email, SDKs, deliverability tooling and SLA, with Notix in a separate third column.
Pay-as-you-go SES against SendGrid's plans on price at volume, setup effort, tooling and support, with Notix in a separate third column.
A marketing suite with a transactional API against a dedicated email API, on free tier, price, SDKs and deliverability tooling.
Two developer-first email APIs on free tier, per-email price, SDKs, validation tooling and SLA, with Notix in a separate third column.
Two of the oldest email APIs compared on price at 50,000 and 100,000, validation, inbound, SLA and support.
Transactional focus against a broader platform, on price per email, inbound routing, validation and SLA.
Postmark's transactional-only stance against SendGrid's scale, on price, free tier, marketing features and SLA.
The newest developer email API against one of the oldest, on free tier, price, SDKs, inbound and SLA.
Two developer-favourite email tools with different shapes, on free tier, pricing model, SDKs, webhooks and SLA, with Notix in a separate third column.
Pricing, sending API, deliverability tooling, SDKs and billing regions, side by side with a read date.
CompareWhat changes when you leave a 60-day trial for a free plan that stays, and where SendGrid's scale still wins.
CompareTen thousand emails for $15 against fifty thousand, and the one thing Postmark has that Notix does not claim.
CompareSame $15 entry, different included volume, and where Mailgun's inbound routing and validation matter.
ComparePer-thousand pricing against a flat plan, and what SES leaves you to build before the first receipt goes out.
AlternativesHonest switch pages for the email APIs people move away from, with the vendor's own numbers and read dates.
Verify a domain, copy an API key, make one call. The free plan does not ask for a card.