Reliable email API. Scale your sending volumes without technological barriers. Use the MessageFlow email API to integrate via REST or SMTP, get full visibility into real-time logs and webhooks, and scale your email campaigns in a flexible pay-as-you-grow model.
Email API and SMTP Relay. Integrate with ease and scale with no limits
11.7 B
Messages a month
Throughput that makes a difference.
0.16 s
Average transit
Your clients are only 0.16 s away from their messages.
99%
Delivery rate
Choose a solution that is unparalleled in quality.
79k+
Clients
Taking care of your business at every step.
Trusted by 79,000+ leading brands
Email API in practice – from integration to delivery
The MessageFlow e-mail API is mission-critical infrastructure designed for technical teams that require reliable email sending, full observability, and flexible scalability. You get a stable API, clear documentation, and developer-friendly tools that simplify both MVP implementation and high-volume production workloads.
RESTful email API (core integration)
Full control over email sending directly from your integrated systems, using your preferred programming language. Work with clearly documented endpoints, clean JSON structures, and ready-made request and response examples.
Ready-to-use code snippets and OpenAPI documentation
Skip the boilerplate. Copy a code snippet (cURL, PHP, Python, Java, Node.js) and send your first test e-mail within minutes of creating an account.
SMTP Relay for legacy and e-commerce systems
Connect existing systems without building a full API integration. Simply update the host, port, and login credentials to start using MessageFlow’s email infrastructure.
Dynamic templates managed in the web app
Separate presentation from application logic. From the backend, you only send a template ID and variables, while email layout and content are managed in the HTML editor with no application redeploy required.
MessageFlow Priority (add-on)
A dedicated delivery path for time-critical messages such as OTPs, 2FA codes, and security alerts. Messages bypass the standard queue, minimizing latency and reducing the risk of delivery bottlenecks.
Getting started with email API and SMTP Relay MessageFlow
Integrating MessageFlow email API into a production environment follows a simple, predictable flow – from authentication to real-time delivery tracking.
Generate an API key in the MessageFlow panel and assign permissions for email sending, logs, and webhooks. Higher plans allow you to use separate keys for test and production environments.
Add the SPF, DKIM, and DMARC records generated in the MessageFlow panel to your DNS configuration. This allows your domain to send email with a trusted sender reputation.
Send emails via:
- REST API – for application backends
- SMTP Relay – for legacy systems and e-commerce platforms
Each request returns a Message ID, which you can use to track delivery status and troubleshoot issues.
Configure webhooks to receive real-time events (delivered, bounced, opened, clicked), enabling automation and full delivery visibility.
SMTP Relay integration connects your system to the MessageFlow infrastructure using secure credentials. No API calls or custom code are required, only correct SMTP server configuration.
Start by creating an SMTP password in the MessageFlow panel. The login (1.accountname.smtp) is fixed. Assign these credentials to the domain or application that will be sending your emails.
If you plan to run test sends, you will need a separate account with an additional IP, for which you will receive a second login (2.accountname.smtp) and can generate a dedicated password.
Add the SPF, DKIM, and DMARC records generated in the MessageFlow panel to your DNS configuration. This allows your domain to send emails with a trusted sender reputation.
Enter the SMTP details in the application or platform that sends your emails (e.g., WordPress, Magento, CRM, ERP):
- SMTP host
- Port
- Encryption type (TLS/SSL)
- SMTP username and password
From this point on, all outgoing emails from your system will be sent through MessageFlow.
Send a test message (such as a password reset or order confirmation), then check its status in the MessageFlow logs. You can also enable webhooks to receive delivery events in real time.
Works with your platform – no plugins required
MessageFlow is compatible with any system that supports the SMTP standard (CMS, e-commerce platforms, CRMs). There’s nothing to install – just enter our server details in your platform settings. We’ve prepared step-by-step guides for the most popular solutions.
Observability, logs, and sending reputation
Full visibility into the e-mail delivery process with no guesswork or hidden data. MessageFlow provides the tools you need for fast diagnostics, trend analysis, and protecting your sending domain’s reputation.
Email API analytics module (add-on)
Turn raw logs into clear, actionable charts. Detect anomalies, track error trends, share dashboards with your team, and respond before issues impact end users.
Domain security and list hygiene
The domain authentication tool generates proper SPF, DKIM, and DMARC records. The system automatically blocks hard bounces and spam traps, protecting your sending domain’s reputation.
Who’s MessageFlow email API for?
Our e-mail API is built for teams that treat email communication as a critical part of their system infrastructure.
E-mail API for e-commerce
Reliable system notifications, including order confirmations, PDF invoices, shipping updates, and post-purchase communication.
E-mail API for fintech
Instant delivery of 2FA codes, OTPs, and security alerts powered by MessageFlow Priority and low-latency routing.
E-mail API for SaaS
Smooth onboarding, account verification, and password resets sent directly from the application backend.
E-mail API for marketing
Run email marketing campaigns from the MessageFlow panel without involving tech teams, using the same infrastructure as transactional sends while maintaining IP separation.
How can MessageFlow email API help you?
Faster debugging and support resolution
Full observability lets you instantly determine whether a message was sent, delivered, or rejected, without guesswork or escalation.
- Searchable logs using Message-ID
- Real-time status webhooks
- Access to raw data at no extra cost
Limit-free scaling (pay-as-you-grow)
Start with a base package and scale email sending as your business grows, without unnecessary limitations.
- No throttling when exceeding plan limits
- Predictable overage pricing
- Option to move to dedicated resources
Low latency for critical communication
Security-related e-mails aren’t queued up with bulk traffic.
- Dedicated priority queue (Fast Lane)
- Separation from standard API/SMTP traffic
- Designed for time-sensitive use cases
One API, multiple channels – the MessageFlow ecosystem
The e-mail API is part of the broader MessageFlow communication ecosystem, designed to deliver a consistent and unified developer experience.
The same REST API, the same authentication, and a consistent JSON format across email, SMS, and mobile push.
Generate separate API keys for different environments and restrict their permissions to specific resources.
Build your own resilience logic: if an email isn’t delivered, automatically trigger an SMS or another channel.
One API, multiple channels
Email API is part of the broader MessageFlow communication ecosystem, built to deliver a consistent developer experience.
FAQ – MessageFlow email API
Email API allows you to send emails directly from your application or backend system, with full control over delivery logs and message status.
You can launch your first integration within minutes using SMTP or REST, supported by ready-to-use code snippets.
Yes. The infrastructure is designed for a high delivery rate, with built-in domain reputation protection and traffic separation.
Transactional e-mails, security notifications, onboarding messages, and other application-generated communication.
Yes. Detailed logs are available in the panel, and your system can also receive automatic status updates via webhooks.
By using the REST email API or the SMTP Relay, depending on your system architecture.
Yes. The platform scales flexibly in a pay-as-you-grow model, without blocking e-mail delivery.
Yes. Data is processed within the EEA, and all communication is encrypted using TLS.