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Resend
Modern email API for developers. Simple, reliable transactional and marketing email delivery built for product teams that need great deliverability and React email templates.
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Design Email for Humans and Agents
Apple Mail and Gmail now generate AI summaries of emails, while agents read messages to automate tasks like logging receipts or tracking deadlines. Summarizers focus on the first 100 to 150 characters, so the main point and call to action must lead the email. Semantic HTML with h1 headings, a descriptive title, lang attributes, and role=‘presentation’ on tables creates a machine-readable outline, yet the Email Markup Consortium found 74% of emails lack an h1 and 96% lack lang. Hidden text styled to be invisible can hijack summaries, as Forcepoint demonstrated, and similar attacks have targeted Gemini in Google Workspace; such practices also trigger security flags. Testing in Gmail, Apple Mail, and Outlook, along with verifying the plain text version, confirms that both humans and agents interpret the email correctly.
Warmup Services Harm Your Deliverability
Warmup services that simulate email engagement harm deliverability because inbox providers detect the pattern and tighten filtering, causing reputation decline that makes recovery harder. Validity’s new Heatwave blocklist identifies domains warmed through synthetic engagement, using signals from its Intelligence Network to automatically list domains crossing a threshold, and over 1.2 million domains have already been listed. The signal is shared with providers including Comcast, Proofpoint, Spamhaus, and SURBL, potentially damaging domain reputation with these providers. A domain on Heatwave receives a permanent record, and even if the domain stops cold outreach, the warming listing stays, making recovery difficult or impossible. Legitimate senders should verify their domain at lookup.validity.tools, obtain proper consent, and increase volume gradually through real engagement, as the domain warms itself through real engagement and there is no shortcut to trust; warmup activity may also run through agencies without the sender’s knowledge.
Welcoming Allie Sperry, our new Customer Success Engineer
Resend has hired Allie Sperry as a Customer Success Engineer to support its growing customer base, bringing experience from Litmus in technical support and Customer.io as a deliverability consultant. Sperry describes herself as an email nerd who enjoys helping developers and builders navigate the complexities of email at scale, and she discovered Resend while building an email sending app for fun using AI tools. She got into software through her older brother’s influence and early experiments with Myspace layouts, which taught her to break down and rebuild code. Her favorite tool is Obsidian for daily notes, and she uses a refillable notebook to draft ideas before uploading photos to Claude or digital notes. Her advice to ambitious software engineers is to focus on the desire to learn rather than knowing everything, and to avoid comparing one’s journey to others, as unique backgrounds create unique work.
Welcoming Gaby Garcia, our new Recruiter
Resend announced the hiring of Gaby Garcia as a new full-cycle recruiter who combines a people-first approach with strategic sourcing and a passion for creating thoughtful, scalable recruiting processes. Garcia holds a background in Psychology, which she says brings curiosity and empathy to her work, and she continually looks for ways to improve how teams hire. She spent the last five years at Automattic hiring engineers and designers, making her well acquainted with developers and the DevTools space. Garcia expressed excitement about Resend’s focus on culture and growing together, stating she loves helping people find a place where they can do meaningful work and feel like they belong. She aims to help Resend grow while being part of that kind of team herself, bringing her expertise to the company’s hiring process.
The Headless Dashboard Initiative
Resend announced a headless dashboard initiative to make all dashboard capabilities available programmatically via the MCP, CLI, and API. Recent releases include the Email Metrics API for deliverability and engagement data, a Headless Webhook API for listing events and replaying deliveries, and a Cancel Broadcast API. The Duplicate Broadcast API copies any broadcast into a draft, and the Share Email API provides expiring read-only email links. The team aims to make the dashboard best-in-class while committing to full headless operation for every future entity. Developers can start building today by connecting the MCP server or using the CLI.
Welcoming Roberto Braga, our new Growth Marketer
Resend welcomes Roberto Braga as its new Growth Marketer, adding a leader with more than 10 years of experience building and scaling technology businesses. He previously co-founded and served as CMO of YC-backed BX Blue, led growth through its acquisition by PicPay, ran organic growth at PicPay with SEO and ASO, and most recently was Reddit’s Country Growth Lead in Brazil. At Reddit, he helped double the platform’s DAU through content and partnership-led growth strategies; at Resend, he plans to create the Growth discipline and systematize the factors driving user acquisition and retention. Braga describes experimentation, channel mixing, email, and user conversations as central to his work, and advises growth marketers to focus on user pains rather than the newest tools or frameworks.
Welcoming Julia Zettel, our new Video Producer
Resend announces that Julia Zettel has joined its team as a Video Producer, bringing more than a decade of experience in video and storytelling from work with brands including Zee.Dog and Globo. She will help the company communicate with customers, produce original content, and tell stories beyond the product through video, education, launches, and the people building with Resend. Julia says her background grew from being surrounded by television and music production, while her studies in Social Communication and AV led her toward narrative-driven visual work; she initially collaborated with Resend on editing, then a full producing and filming project before joining full time. She cites Adobe Premiere as her primary tool, Adobe Podcast for noisy or windy recordings, and recommends accepting challenging projects and learning from experienced people alongside online tutorials and AI.
Welcoming Kiersti Esparza, our new Deliverability Engineer
Resend introduces Kiersti Esparza as a Deliverability Engineer on its Trust & Safety Squad, where she will help scale sending infrastructure as the company grows. She brings nearly 20 years in email deliverability, including building teams at Marketo, consulting at Twilio, and deliverability engineering at Klaviyo. Esparza describes the work as a combination of interpreting datasets, understanding email technology, and adapting to evolving authentication in an ongoing contest between bad actors and receivers. She says Resend attracted her with developer-oriented infrastructure, hands-on foundational work, and a culture centered on transparency and partnership, while advising operators to master overlooked infrastructure because its scarcity creates leverage.
The Email Verification API
The proposed Email Verification API lets a browser verify that a submitted email address belongs to the user without sending them away from the current form to retrieve an OTP or magic link. Its flow involves the user, browser, mailbox provider (issuer), and application server (verifier): after mailbox registration, the browser and issuer create a token that is submitted with the address and checked server-side. Implementation requires an email input, a hidden email-verification-token input with a session-bound random nonce, and token verification using the site origin as audience; a JavaScript package handles parsing, lookups, and signature checks. The proposal is currently limited to Chrome’s origin trial and Gmail mailbox verification, so the source recommends progressive enhancement and other verification APIs where unavailable.
How APRF Helps You Understand Your Email Reputation
Aggregate Performance Reporting (APRF) is a draft standard for email deliverability feedback backed by contributors from Comcast, Google, and Iterable. It gives senders aggregated, intentionally bucketed signals about message classification—such as inbox or unwanted—and user engagement, categorized as positive, negative, or neutral. It also describes daily JSON reports delivered to a DNS-configured address, with provider-specific bucket definitions optionally documented in extra_info. Senders can configure a TXT record derived from the DKIM selector and domain, then use the optional sdi attribute and email header to segment results by business, region, campaign, or other values. The sample shows separate classification and engagement data for marketing and transactional segments, while acknowledging that counts are approximate; APRF is not yet adopted by an IETF working group, Comcast sends reports, and Gmail does not yet.
Welcoming Laura Beatris, our new Software Engineer
Resend announces that Laura Beatris is joining its team as a Software Engineer. She previously worked at Clerk and WorkOS, where she shipped authentication products with an emphasis on developer experience, and she has spoken on React, TypeScript, and learning in public. Laura describes a path that began with learning Python from free tutorials, continued through a technical degree and early project-building after repeated internship rejections, and eventually led to Amsterdam in 2021. At Resend, she says she was drawn to products where details matter, a culture of learning in public, and a new problem space for improving her developer-experience judgment; her advice is to learn, create, then teach, because teaching helps knowledge stick.
Welcoming Fabio Kubo, our new Software Engineer
Resend announces Fabio Kubo as a new software engineer joining its software engineering team. With more than 10 years of experience, Kubo has helped scale products to millions of customers at iFood and Nu, and he will bring that experience to Resend as the platform grows. He says the product, rapid growth, technical challenges, and fully public handbook attracted him, with the company’s values, culture, working style, and transparency resonating particularly strongly. Kubo also discusses customer feedback as a source of motivation, names Notion and multi-cursor editing as favorite tools, and advises ambitious engineers to learn how they learn and understand underlying concepts when navigating new domains, technologies, and tools.
Welcoming Mateus Resende, our new Software Engineer
Resend introduces Mateus Resende as a Software Engineer based in Belo Horizonte, Brazil. He began working in software in 2015, first as a Ruby and Ruby on Rails developer before moving across domains including e-commerce recommendations, vehicle tracking, fintech, and email systems. A snowstorm during his exchange at SUNY Buffalo led him to discover MIT OpenCourseWare, code for hours, and later switch from Electrical Engineering to Computer Science. At Resend, he says its remote and async culture, extensive documentation, and developer-oriented product and company shaped his decision to join. His approach to engineering emphasizes balancing quality with speed and tailoring solutions to users and reviewers, while he recommends fundamentals such as testing, Domain-Driven Design, and Evolutionary Architectures over relying on hyped LLM coding techniques.
How to Show Your Logo in Apple Mail
Displaying a company logo in Apple Mail can improve inbox recognition, trust, and visual distinctiveness, while cited studies associate logos with higher brand recall, open rates, purchase likelihood, and email confidence. The article presents Apple Branded Mail, a proprietary format shipped in iOS 18.2 in 2024, as a free alternative to inconsistent provider settings and the paid certificates and trademarks sometimes needed for broad BIMI coverage. Setup begins with a DMARC policy of p=quarantine or p=reject, then uses Apple Business Connect to add a brand, upload a PNG, HEIF, or JPEG logo at least 1024 × 1024 pixels, select domains, and verify identity. Verification can take up to seven business days; root-domain branding covers unconfigured subdomains, while brands needing broader client coverage are directed to BIMI.
Welcoming Phil Nash, our new Developer Experience Engineer
Phil Nash is joining Resend as a Developer Experience (DX) Engineer after eight years at Twilio and subsequent work at IBM. He has taught developers through talks, articles, and live coding, and will focus on helping developers become more productive. His path into software began with building an HTML page at 13, continued through maths and computer science studies, and led to front-end development after creating a WordPress blog and writing about what he learned. Nash says he joined because he had used Resend for a personal-site contact form, built a simple TypeScript API client, and wanted to help make email a better experience for developers. He recommends sharing new learning through writing, presentations, videos, or other community contributions.
The New DMARC is Here
DMARCbis is finalized as three Standards Track RFCs: RFC 9989 for the core protocol, RFC 9990 for aggregate reporting, and RFC 9991 for failure reporting. Existing DMARC records continue working as before, so most senders do not need immediate changes. The largest behavioral update replaces Public Suffix List lookups with an algorithmic DNS Tree Walk, in which receivers query _dmarc records up the DNS hierarchy; the psd tag can declare hierarchy boundaries. The pct tag is replaced by boolean t, while np can specify a policy for non-existent subdomains, including np=reject. Reporting knobs rf and ri are removed, but rua and ruf remain available; senders using fractional pct should use a none-to-quarantine-to-reject rollout, keep reading reports, and avoid rushing to reject.
Welcoming Matt Gilbert, our new Data Analyst
Resend announces Matt Gilbert as a Data Analyst on its Trust & Safety team. He spent 10 years as a Deliverability Engineer at Mailchimp, handling Delivery-team data and maintaining sending infrastructure that pushed around a billion emails a day, after earlier work on the Mandrill transactional mail service. Gilbert describes email delivery as a multidisciplinary field spanning MTA operations, data engineering, analytics, mail-queue performance, and troubleshooting delivery and inbox-placement problems, which led him to specialize in data engineering and analytics. He says he joined Resend because email remains an open, globally available way for services to communicate, and plans to help build data-driven capabilities and intelligence that enable customers to send better and reach inboxes quickly.
Sunsetting new.email
Resend is sunsetting new.email, which will remain available for template exports until August 7, 2026, before stopping new prompts and sends. Launched in February 2025, the tool let anyone create email templates with natural language, using React Email components and deliverability lessons from sending millions of emails daily; its goal was consistent, beautiful, responsive email. Resend says the core bet was right, but a separate brand and stack—repository, infrastructure, deployment, and operational conventions—made the product harder to maintain, while market feedback showed users did not need new templates constantly. The product’s ideas are moving into the Resend editor, which offers URL-based brand extraction, AI block rewriting, LLM content review, and email creation and editing through the Resend MCP server.
Engineering a Vercel Chat Adapter
Vercel’s Chat SDK supports bots across multiple chat platforms, but those channels can be ephemeral and leave conversations buried in feeds and threads. Email offers a persistent, widely used channel, so Resend built an official adapter that treats email as bidirectional chat. Inbound mail arrives through Resend webhooks and triggers Chat SDK handlers, while outbound messages use the Resend API. The adapter reconstructs threads from In-Reply-To and References headers, tracking message-to-thread mappings in an in-memory Map and generating IDs from the sender address and a SHA-256 prefix of the root Message-ID. It also translates Chat SDK messages, including markdown and CardElement structures, into email HTML and plain-text content through React Email components, trading richer native chat semantics for email’s reach and simpler delivery model.
Welcoming Kelsey Mills, our new Operations Generalist
Kelsey Mills is joining Resend as an Operations Generalist based in Vancouver, Washington, with responsibility for the logistics behind upcoming offsites, meetups, and conferences. She describes operations as work that suits her organizational instincts: managing many moving parts, absorbing new information, balancing tasks, and refining processes for greater efficiency. Mills says Resend’s attention to detail, care of craft, culture, and community attracted her during a period of growth and scalability. Outside work, she mentions a Michigan sunset as her home-screen image, Hawaii as a favorite destination, the Notes app as a reliable tool, and Ctrl + Cmd + Spacebar as her favorite hotkey; her advice to ambitious operations generalists is to value their work, keep raising their hands, and say yes to opportunities.
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