Senior Email​/SMS Deliverability Engineer – Remote

Overview

Join a nimble, product-focused team where your work directly supports a platform used by millions of people worldwide. Greenvelope was founded in Seattle in 2008 with a simple idea: create beautiful, effortless, environmentally friendly digital invitations. Sixteen years later, we're still crafting thoughtful experiences for hosts and guests all over the world.

We're a small, tight-knit team of fewer than 20 people, and we like it that way. Our size means less red tape and more autonomy. Several team members have celebrated 10+ year anniversaries, and we're intentional about maintaining a culture where smart, kind people enjoy working together long-term.

Greenvelope delivers millions of digital invitations and event communications each year. Email and SMS delivery is mission-critical to our product and our brand. We are looking for an engineer to rethink and rebuild our messaging engine end-to-end — designing a modern, resilient platform that ensures fast, reliable, and trusted delivery at scale.

This is a new build opportunity within an established product. Our current systems work, but they were not built for the scale and reliability standards we need going forward. You will have the mandate to architect something better from the ground up.

You will be the internal expert on deliverability, messaging infrastructure, and provider integrations — blending backend engineering with deep domain expertise in email and SMS systems. Because our customers depend on time-sensitive communications (wedding invitations, event reminders, RSVP confirmations), even brief outages have real consequences. High availability and redundancy are core to how we design and operate every layer of the messaging pipeline.

ASP.NET, SQL Server, Windows Server. The codebase is primarily  today, moving toward C# for new development. The messaging pipeline relies on background services, scheduled tasks, and webhook processors. You will spend meaningful time writing and maintaining code — not just configuring third-party tools — and should be comfortable working in  while helping us migrate toward C#.

• Redesign and rebuild Greenvelope's email and SMS delivery systems from the ground up. This is not a maintenance role.
• Own architecture and development of the new messaging platform in .NET ( and C#).
• Design fault-tolerant background services and job processors that assemble, route, and dispatch millions of messages.
• Architect for high availability and redundancy — no single point of failure, graceful degradation, and automatic recovery when components or providers go down.
• Build background jobs and scheduled tasks for message batching, retry logic, and delivery orchestration.
• Implement and manage DKIM, SPF, DMARC, and custom sending domains, including enterprise customers sending from their own domains.
• Diagnose and resolve deliverability issues including spam filtering, throttling, and ISP rejections.
• Partner with support and product teams to investigate non-delivery reports and provide clear root-cause analysis.
• Build and maintain .NET integration layers with providers such as Send Grid, Spark Post, Twilio, and Telnyx — including REST API clients, webhook receivers, and event processors.
• Evaluate providers, routing strategies, and automatic failover mechanisms to ensure delivery even during provider degradation.
• Maintain redundant provider paths so no single vendor dependency can halt delivery.
• Manage 10
  
  DLC registration and compliance, including brand registration, campaign vetting, and throughput management.
• Stay current with TCR (The Campaign Registry) requirements and carrier-specific registration workflows, opt‑in/opt‑out compliance, and content guidelines.
• Monitor and respond to carrier filtering events, throughput changes, and registration status updates.
• Build dashboards and alerts to track delivery rates, bounce types, spam complaints, and SMS failures.
• Investigate delivery anomalies and proactively identify risks before they impact customers.
• Improve observability around job processing, retries, and provider responses.
• Work with product, support, and enterprise sales to support high‑value customers and complex…