RelayCore delivers enterprise-grade, permission-based transactional messaging infrastructure for SaaS platforms, fintech applications, and enterprise systems. SMTP relay, REST API, real-time monitoring — all in one secure cloud platform.
RelayCore is purpose-built for system-generated, permission-based transactional communications. Not marketing. Not bulk sending. Infrastructure for SaaS.
Dedicated IP pools with reputation monitoring. TLS encryption on all connections. SPF, DKIM, and DMARC enforcement. Built for high-volume transactional workloads with automatic failover across multiple send paths.
Send transactional messages via simple REST calls. SDKs for Node.js, Python, Go, PHP, Ruby, and Java. Webhook events, idempotent requests, and sub-second delivery confirmation.
Live dashboards showing delivery rates, bounce classification, complaint tracking, and queue health. Instant alerts when metrics exceed thresholds.
Automatic opt-out enforcement. Bounce and complaint suppression applied system-wide in real time. Full suppression list export and API management.
Double opt-in workflow builder. Consent timestamp recording. Full audit log for compliance evidence. Recommended for all recipient segments.
Templated delivery for OTP codes, password resets, account alerts, billing notifications, and system events. Low-latency, sub-500ms queue processing.
Enterprise plans include dedicated IP pools for reputation isolation. Automated warmup scheduling, blacklist monitoring, and feedback loop registration with major ISPs.
Hard and soft bounce classification. ISP-level complaint rate monitoring. Automatic account alerts at 0.08% complaint threshold — well below industry danger zones.
Step-by-step SPF, DKIM, and DMARC configuration guides. DNS verification tooling. Authentication health scoring included in all plans.
RelayCore operates on a strict permission-based policy. Every recipient must be a fully opted-in user of your platform. Purchased lists, scraped contacts, and third-party data are strictly prohibited and result in immediate account suspension.
"We migrated our transactional email stack to RelayCore six months ago. Delivery rates jumped from 94% to 99.2%, and the compliance infrastructure gave our legal team the confidence they needed for our SOC 2 audit."
"As a fintech, our OTP and account alert infrastructure is mission-critical. RelayCore's sub-400ms delivery, dedicated IPs, and real-time monitoring made them the obvious choice. Outstanding API quality."
"The suppression list automation and bounce management alone saved us from a major deliverability crisis. RelayCore's team helped us implement double opt-in across our 300k user base without a single incident."
Start with 10,000 free transactional sends per month. No credit card required. Full API access from day one.
RelayCore provides every component of a production transactional messaging infrastructure — from secure SMTP relay and REST API to real-time analytics and compliance automation.
MESSAGE DELIVERY ARCHITECTURE
Enterprise SMTP infrastructure with TLS 1.3 encryption, DKIM signing, and IP reputation management. Connect your application via standard SMTP ports or our enhanced relay with higher throughput limits.
JSON-based RESTful API with idempotent sends, batch endpoints, webhook callbacks, and real-time delivery status. Rate limits are generous and scale with your plan tier.
Real-time dashboards with delivery rates, bounce classification, complaint monitoring, and queue health. Exportable reports in CSV, JSON, and PDF formats.
Build on RelayCore's transactional messaging API. RESTful, predictable, and fully documented.
const RelayCore = require('@relaycore/sdk'); const client = new RelayCore({ apiKey: process.env.RELAYCORE_API_KEY }); const result = await client.messages.send({ to: 'user@example.com', from: 'auth@yourapp.com', fromName: 'YourApp Security', subject: 'Your verification code', type: 'transactional', html: `<p>Your OTP: <strong>${'{'}otp{'}'}</strong></p>`, variables: { otp: 482901 }, tags: ['otp', 'authentication'] }); console.log(result.id); // msg_2xKrP9QbNmZ4a1 console.log(result.status); // queued
{
"event": "message.delivered",
"id": "evt_9xMqA3YbKn1Z",
"timestamp": "2025-03-14T19:22:11Z",
"data": {
"message_id": "msg_2xKrP9QbNmZ4a1",
"to": "user@example.com",
"delivered_at": "2025-03-14T19:22:10Z",
"latency_ms": 312,
"ip": "209.85.220.41",
"isp": "Google (Gmail)"
}
}
RelayCore's infrastructure is designed from the ground up for enterprise security and regulatory compliance. Permission-based delivery is not a feature — it is the product.
RelayCore provides infrastructure exclusively for transactional communications sent to fully opted-in recipients. The use of purchased email lists, scraped contacts, harvested data, or any third-party list is strictly prohibited and will result in immediate, permanent account suspension without refund. All senders are subject to continuous monitoring for compliance violations.
All API communication is secured with TLS 1.3. SMTP relay connections enforce STARTTLS with certificate validation. DKIM signing is applied to all outbound messages with 2048-bit RSA keys. SPF records are auto-generated for your sending domains.
Deployed across multiple AWS regions with auto-failover. All data encrypted at rest with AES-256. Network segmentation with VPC isolation. Regular penetration testing by independent third-party security firms. Zero-trust access model for all internal systems.
SOC 2 Type II certified. Annual GDPR compliance audits. CCPA-aligned data handling practices. CAN-SPAM compliant by design. EU-US Data Privacy Framework participant. HIPAA-compatible infrastructure available on Enterprise plans.
24/7 automated abuse detection monitors complaint rates, bounce patterns, and send behavior anomalies. Accounts triggering thresholds (complaint rate >0.1%, bounce rate >5%) receive automated warnings and throttling. Repeat violations result in suspension.
How RelayCore meets the requirements of major data protection and anti-spam regulations.
| Regulation | Key Requirement | RelayCore Implementation | Status |
|---|---|---|---|
| CAN-SPAM Act | Opt-out mechanism, accurate headers, physical address | One-click unsubscribe enforced, suppression automation, required header validation | Compliant |
| GDPR (EU) | Lawful basis, data subject rights, processing records, DPA | Consent recording, right-to-erasure API, processing logs, DPA available, EU data residency option | Compliant |
| CCPA (California) | Right to know, opt-out of sale, data deletion | Data export API, no data resale, deletion request workflow, privacy policy aligned | Compliant |
| CASL (Canada) | Express consent for commercial messages | Double opt-in workflow, consent timestamp recording, audit trails | Compliant |
| SOC 2 Type II | Security, availability, confidentiality controls | Annual audit by accredited firm. Report available under NDA for Enterprise clients | Certified |
| HIPAA | PHI handling, BAA, access controls | BAA available on Enterprise plans. PHI transmission encrypted. Audit logging enabled. | Enterprise Only |
v=spf1 include:spf.relaycore.us ~all
Add as TXT record to your domain's DNS. Authorizes RelayCore's IP ranges to send on your behalf.
rc-2025._domainkey.yourdomain.com CNAME dkim.relaycore.us
CNAME delegation allows RelayCore to rotate DKIM keys automatically for maximum security.
v=DMARC1; p=quarantine; rua=mailto:dmarc@relaycore.us; pct=100
DMARC enforcement policy. RelayCore aggregates reports and surfaces issues in your dashboard.
No setup fees. No hidden charges. Pay for what you send. All plans include full API access, compliance tools, and real-time monitoring.
For developers building and testing transactional messaging integrations.
For growing SaaS companies with active user bases requiring reliable transactional infrastructure.
For high-volume platforms, fintech companies, and enterprises with advanced compliance requirements.
No. RelayCore is purpose-built for transactional communications only — OTPs, account notifications, password resets, billing alerts, and system-generated messages. Promotional or marketing emails are prohibited.
Transactional emails are triggered by a user action or system event: account verification, OTP codes, password resets, purchase confirmations, shipping notifications, and account alerts.
Yes. The Starter plan includes 10,000 sends per month permanently free. Growth plans include a 14-day trial with full feature access. No credit card required to start.
Plans include a monthly send quota. Additional sends are billed at the per-1K rate shown. You'll receive an alert at 80% quota usage. Billing is monthly, and you can upgrade, downgrade, or cancel anytime.
RelayCore was founded in 2020 by a team of infrastructure engineers who believed that transactional email delivery should be fast, reliable, compliant, and — most importantly — ethical.
We built RelayCore after experiencing firsthand how difficult it was to find an email infrastructure provider that placed compliance and permission-based sending at the center of their product — not as an afterthought.
Today, RelayCore powers the transactional messaging infrastructure for over 185 enterprise clients across SaaS, fintech, healthcare technology, and e-commerce — processing over 2.4 billion transactional messages annually.
Permission-based messaging isn't a constraint on our platform — it is the platform. Every product decision starts with "does this support ethical, consensual communication?"
Your users expect their OTP within seconds. We obsess over every millisecond of latency, every failover scenario, and every edge case in delivery infrastructure.
APIs should be a joy to use. Documentation should answer questions before they're asked. Support should feel like talking to a teammate who knows the codebase.
Legal Name: RelayCore, Inc.
State of Incorporation: Delaware, USA
Business Registration: EIN 87-3341092
Delaware SOS File No.: 7824103
Headquarters: Austin, Texas
Founded: 2020
Website: relaycore.us
Support: support@relaycore.us
Whether you're evaluating RelayCore for your platform or need support, our team is ready to help.
RelayCore, Inc. is committed to protecting the privacy of our customers and the end users they serve. This Privacy Policy explains how we collect, use, and protect information.
We collect information you provide when you create an account, use our services, or contact us for support. This includes:
RelayCore processes transactional message content and recipient addresses solely to deliver the requested messages. We do not analyze message content for advertising purposes, sell recipient data, or share message content with third parties except as required to deliver the service (e.g., ISP delivery).
Message metadata (delivery status, timestamps, bounces) is retained for 90 days on Growth plans and configurable on Enterprise plans.
We use collected information to:
We do not sell, rent, or trade personal information. We share data only with service providers necessary to operate the platform (cloud infrastructure, payment processing, monitoring tools), and only under data processing agreements requiring equivalent protections.
Depending on your jurisdiction, you may have rights to access, correct, delete, or export your personal data. To exercise these rights, contact privacy@relaycore.us. We respond to verified requests within 30 days.
For EU residents, RelayCore acts as a data processor for message recipient data and as a data controller for account data. We are a participant in the EU-US Data Privacy Framework. EU data residency is available on Enterprise plans. Data Processing Agreements (DPAs) are available upon request.
We employ industry-standard security measures including TLS encryption, AES-256 encryption at rest, network isolation, regular penetration testing, and access controls. We are SOC 2 Type II certified.
Privacy inquiries: privacy@relaycore.us
RelayCore, Inc. · 3300 N Interstate Hwy 35, Suite 500 · Austin, TX 78705
By accessing or using the RelayCore platform ("Service"), you agree to be bound by these Terms of Service ("Terms"). If you do not agree, you may not use the Service. These Terms constitute a legally binding agreement between you or your organization ("Customer") and RelayCore, Inc. ("RelayCore").
RelayCore provides a cloud-based transactional messaging infrastructure platform, including SMTP relay services, REST API access, delivery monitoring, suppression list management, and related developer tools. The Service is designed exclusively for transactional communications.
The Service may only be used to send:
⚠️ The following uses are strictly prohibited and will result in immediate account termination.
RelayCore reserves the right to suspend or terminate accounts immediately and without notice for violations of these Terms or the Acceptable Use Policy. Accounts exceeding complaint rate thresholds of 0.1% or bounce rate thresholds of 5% may be suspended pending investigation.
RelayCore provides a 99.9% uptime SLA for Growth plans and 99.99% for Enterprise plans. SLA credits are calculated monthly based on verified downtime. Scheduled maintenance windows are excluded from SLA calculations.
To the maximum extent permitted by law, RelayCore's liability for any claim arising from or related to the Service is limited to the fees paid in the 12 months preceding the claim. RelayCore is not liable for indirect, incidental, or consequential damages.
These Terms are governed by the laws of the State of Delaware, USA. Disputes shall be resolved by binding arbitration in Austin, Texas.
Legal notices: legal@relaycore.us · RelayCore, Inc. · 3300 N Interstate Hwy 35, Suite 500 · Austin, TX 78705
RelayCore is a transactional messaging infrastructure platform. This policy defines what constitutes acceptable use and what will result in suspension or termination of your account.
You may use RelayCore to send the following categories of transactional communications to users who have provided explicit, verifiable consent:
⚠️ The following uses violate this policy and will result in immediate account termination.
RelayCore employs automated systems to monitor sending patterns, complaint rates, bounce rates, and content signals. Accounts that exceed the following thresholds will be flagged for review:
To report abuse of the RelayCore platform, contact abuse@relaycore.us. All abuse reports are investigated within 24 hours.
RelayCore has a zero-tolerance policy toward spam. Our infrastructure is designed exclusively for permission-based transactional messaging. This policy explains our stance, practices, and enforcement mechanisms.
RelayCore does not tolerate spam of any kind. We define spam as any electronic message sent to a recipient who has not given clear, explicit, informed consent to receive communications from the sending party. This definition applies regardless of message volume, content type, or sender intent.
All recipients of messages sent through RelayCore's infrastructure must meet the following consent criteria:
RelayCore strongly recommends and supports double opt-in (confirmed opt-in) processes for all sender/recipient relationships. Double opt-in requires the recipient to confirm their email address via a separate confirmation message before being added to your sending list. RelayCore's platform includes double opt-in workflow tools for all paid plans.
Every message sent through RelayCore must include a clear, functional, and easy-to-use unsubscribe mechanism. Upon an unsubscribe request:
The following list acquisition methods are strictly prohibited:
All transactional messages sent through RelayCore must comply with the CAN-SPAM Act requirements, including accurate sender information, non-deceptive subject lines, physical mailing address inclusion, and functioning opt-out mechanisms.
Accounts found to be sending spam, using prohibited lists, or circumventing suppression will be terminated immediately and permanently without refund. RelayCore cooperates fully with law enforcement and regulatory agencies investigating spam complaints.
Report spam sent via RelayCore: abuse@relaycore.us
RelayCore is committed to full compliance with the General Data Protection Regulation (GDPR) (EU) 2016/679, the California Consumer Privacy Act (CCPA), and applicable data protection frameworks. This page explains our approach, your rights, and how to exercise them.
RelayCore acts in two distinct roles under GDPR:
Customers using RelayCore are responsible for ensuring they have a lawful basis for sending transactional communications to their users under GDPR Article 6.
RelayCore makes a Data Processing Agreement available to all customers upon request. The DPA establishes the rights and obligations of each party in relation to personal data processed via the platform. To request a DPA, contact privacy@relaycore.us.
Enterprise plan customers may elect to store all account and message data within the European Union (AWS eu-west-1, Frankfurt). EU data residency requests must be made during onboarding or via a support ticket. Message processing for delivery will still route through global infrastructure, but no data will persist outside the EU region.
RelayCore provides mechanisms to support the following data subject rights:
To exercise any of these rights, contact privacy@relaycore.us. We respond to verified requests within 30 days.
California residents have the right to know what personal information we collect, the right to delete personal information, the right to opt out of any sale of personal information (note: RelayCore does not sell personal information), and the right to non-discrimination for exercising these rights.
RelayCore participates in the EU-US Data Privacy Framework (DPF). For transfers of EU personal data to the United States, we rely on Standard Contractual Clauses (SCCs) as the legal transfer mechanism, available within our DPA.
We implement appropriate technical and organizational measures to protect personal data, including: TLS 1.3 encryption in transit, AES-256 encryption at rest, role-based access controls, audit logging, and regular security assessments. Our SOC 2 Type II certification provides independent verification of these controls.
In the event of a personal data breach affecting EU data subjects, RelayCore will notify affected customers within 72 hours of becoming aware of the breach, to the extent such notification is required under GDPR Article 33.
Data Protection Officer: privacy@relaycore.us
EU Representative: [EU Rep Contact Available in DPA]
RelayCore, Inc. · 3300 N Interstate Hwy 35, Suite 500 · Austin, TX 78705