Email deliverability is the most overlooked operational risk in a UK competition business, and the one that quietly destroys customer trust when it goes wrong. A competition operator processing 7,000 orders a month is sending 7,000+ ticket confirmation emails, draw close notifications, instant win alerts, and winner contact emails. If those emails land in spam, customers do not receive their entries, complaints multiply, refunds spike, and reputation collapses. Across one recent Mailgun sample from a Nera-built site, 99.22% of competition transactional emails delivered to the inbox with a 0% complaint rate. That is the benchmark to aim for, and it requires a deliberate transactional stack, the right subdomain pattern, and the strict separation of transactional from marketing email.

Nera Marketing audits the email infrastructure on every competition build we ship. The deliverability gap between operators who treat email as launch infrastructure and those who treat it as a post-launch fix is consistent, predictable, and almost always avoidable with the right stack configured from day one.

Why should you not use Klaviyo or marketing tools for transactional competition emails?

Klaviyo and similar marketing platforms are designed for campaigns, segments, and lifecycle flows, not transactional confirmations. Sending ticket confirmations through marketing infrastructure risks deliverability problems on the emails that matter most, because the sender reputation, complaint thresholds, and infrastructure are optimised for marketing workflows. UK competition operators must keep these two channels strictly separated.

Three reasons the separation matters:

• Different deliverability requirements. Marketing email tolerates 10 to 20% spam folder placement because the upside of a sent campaign offsets the inboxing loss. Transactional email cannot tolerate any spam placement, because a buyer who does not receive their ticket confirmation will assume their entry failed and trigger a refund or complaint.
• Complaint contamination. A marketing email with a 0.2% complaint rate is healthy. The same 0.2% complaint rate on transactional sends will tank your sender reputation and pull future transactional emails into spam. Keeping the two channels separated protects the transactional reputation that has to stay clean.
• GDPR consent boundaries. Transactional email (ticket confirmations, winner notifications, payment receipts) sends under “legitimate interest” or contract necessity. Marketing email requires explicit opt-in consent. Running both through the same provider creates audit and consent-tracking complexity that is hard to defend if challenged.

The practical setup: Klaviyo (or your marketing platform of choice) handles competition launches, abandoned cart recovery, newsletters, and re-engagement. A dedicated transactional provider handles every email triggered by an order, draw event, or winner action.

Most operators do not notice email deliverability issues until customers start emailing about missing ticket confirmations. Nera Marketing surfaces inbox placement rate as a launch-day metric, not a post-launch fire.

The transactional email stack that works for UK competition sites

The default transactional stack on Nera-built UK competition websites is Mailgun as the email provider, FluentSMTP as the WordPress connector plugin, and a dedicated sending subdomain configured with SPF, DKIM, and DMARC records. This combination produces the 99%+ delivery rates and near-zero complaint rates that competition operators need to scale without trust collapse.

Nera Marketing benchmarks 99%+ inbox placement on transactional emails for every operator we onboard with the right stack configured before launch.

Nera Marketing recommends this stack as the default for every competition site build because it separates transactional and marketing email at the domain level, which is the single biggest deliverability lever an operator can pull before launch.

The three components and what each does:

• Mailgun (the email provider). Handles the actual sending, deliverability, IP reputation, and bounce management. Mailgun is built for transactional volume and its reputation infrastructure is shared across reputable senders, which keeps your sending reputation strong even from day one. Free tier covers 100 emails per day for testing; paid tiers start at around £12 per month.
• FluentSMTP (the WordPress plugin). Connects your WordPress and WooCommerce site to Mailgun via the API, replacing the default PHP mail function (which has terrible deliverability). FluentSMTP gives you live previewing of every email sent, a log of failed sends with the reason, and easy reconnection if anything breaks. It is the layer that turns WordPress email from unreliable to enterprise-grade.
• The sending subdomain. Configured at the DNS level (SPF, DKIM, DMARC records on a dedicated subdomain like `send.yourcompetition.co.uk`). This is where most operators get deliverability wrong, and it is covered in detail below.

Alternative providers worth knowing about, all supported by FluentSMTP: SendGrid (industry standard, slightly more expensive than Mailgun), Postmark (premium-priced but the fastest transactional speeds), Amazon SES (cheapest at scale but requires more setup expertise), Brevo (formerly Sendinblue), SparkPost, Netcore, and Elastic Email. What you should never use: Google Workspace or Microsoft 365 SMTP (designed for personal email, not transactional bulk), and the default WordPress PHP mail (zero deliverability protection, will land in spam immediately).

How much does email infrastructure cost for a UK competition operator?

For a UK competition operator sending up to 50,000 transactional emails per month, the Mailgun Foundation tier at approximately £28 per month is the recommended starting point. Below 10,000 emails per month the Basic tier at approximately £12 per month is enough. Above 100,000 emails per month the Scale tier at approximately £71 per month adds dedicated IP pools and faster send-time optimisation.

Approximate Mailgun pricing in GBP at current rates:

Tier	Approx. monthly cost	Monthly email volume	Best for
Free	£0	100 emails per day	Testing only, not for live operators
Basic	~£12	10,000 emails	Smaller operators running one or two competitions per month
Foundation (recommended)	~£28	50,000 emails	Standard UK competition operator profile
Scale	~£71	100,000 emails	High-volume operators with multiple instant win competitions

Overages on the Foundation tier are around £1.02 per 1,000 additional emails sent.

Every Nera Marketing competition website build and every Nera Performance Hosting package includes the complete transactional email setup as standard. That covers Mailgun account configuration, FluentSMTP plugin installation, subdomain DNS records (SPF, DKIM, DMARC alignment), warm-up schedule management, and ongoing deliverability monitoring across the operator’s sending domain. Operators not on Nera hosting handle this themselves or use their existing developer to configure. The typical setup time for a competition operator working with their own developer is one to two working days if the developer is familiar with transactional email stacks.

The total cost of email infrastructure for a typical UK competition operator sits between £12 and £30 per month, which is negligible compared to the cost of customer complaints and refunds caused by spam placement of ticket confirmations.

Amazon SES vs Mailgun: cheaper long term, harder to operate

Amazon Simple Email Service (SES) costs a fraction of Mailgun at scale. Per Amazon SES published pricing, at 100,000 transactional emails per month SES bills approximately £8 in email charges compared to Mailgun’s Foundation tier at £28 per month. At 1,000,000 emails per month the gap widens to roughly £3,000 or more per year in Amazon’s favour. The saving is real, and for a high-volume operator running a single brand it is worth taking seriously.

Approximate cost comparison for a UK competition operator:

Monthly volume	Mailgun (per month)	Amazon SES (per month)	Annual saving with SES
100,000 emails	£28 to £75	~£8	£240 to £800
500,000 emails	£150 to £250	~£40	£1,300 to £2,500
1,000,000 emails	£275 to £450	~£80	£2,300 to £4,400

The trade off is operational overhead. Amazon SES gives you a raw email sending API. Everything else you build yourself or pay for separately.

Every AWS SES account starts in sandbox mode with a 200 emails per day cap. Production access requires submitting a support ticket that describes your use case, expected volume, how you handle bounces and complaints, and the source of your recipient lists. Amazon reviews each request individually and typical turnaround is 24 to 72 hours. Failure to respond promptly to a bounce or complaint spike after approval can result in your account being placed back under review or suspended.

Once out of the sandbox, SES gives you the sending API but no built in dashboard for delivery rates, no template management UI, no automated bounce suppression, and no reputation alerting. Each of those needs to be built or plumbed via CloudWatch, SNS webhooks, and third party tools such as Postmark Insights, which typically add £10 to £30 per month back onto the bill.

At Nera Marketing we tested Amazon SES against Mailgun on a subset of client domains and made the call to standardise on Mailgun for the client fleet. The engineering time required to run SES across 40+ sending domains, each with its own bounce handler, complaint monitor, and reputation dashboard, cost more in operational overhead than the pricing saved. For an agency running multiple client sending domains, that trade off usually favours Mailgun.

For a single brand competition operator sending more than 200,000 emails per month with in house engineering capacity, Amazon SES is the cheaper long term choice. Everyone else is better served by Mailgun’s built in tooling.

What email sending subdomain pattern should you use?

UK competition operators should never send transactional email from their main competition website domain. Use a dedicated sending subdomain such as `send.yourcompetition.co.uk` or `website.yourcompetition.co.uk` with its own SPF, DKIM, and DMARC records configured for the email provider in use. This separates your sending reputation from your website’s main domain reputation and is the single most-skipped step in deliverability setup.

Three reasons the subdomain matters:

• Reputation isolation. If a transactional issue affects deliverability, the damage is contained to the sending subdomain. Your main domain (and any other future email use cases like Google Workspace for the operator’s team email) is protected.
• Provider authentication. SPF, DKIM, and DMARC records can be configured precisely for the email provider in use without interfering with other DNS records on the main domain. This is what authenticates your emails to receiving servers like Gmail, Outlook, and Apple Mail.
• Switchover flexibility. If you change email providers (Mailgun to Postmark, for example), the subdomain DNS records change without affecting any other infrastructure. The main domain stays untouched.

Subdomain patterns Nera-built operators use in practice: `send.yourcompetition.co.uk`, `website.yourcompetition.co.uk`, `mail.yourcompetition.co.uk`, or `email.yourcompetition.co.uk`. The exact subdomain name does not matter as long as it is dedicated and not used for anything else. What matters is that it is not the main domain, and that its DNS records are configured correctly for the provider.

What you must not do: send from the main domain directly (e.g. `info@yourcompetition.co.uk` via the main domain’s MX records), and never configure SPF or DKIM on the main domain for the email provider. Both will gradually erode your main domain reputation in ways that are hard to recover from.

The deliverability outcomes mature competition sites achieve

Nera Marketing manages the transactional email stack across a fleet of over 40 UK competition websites. Across July 2026, the fleet sent 98,496 transactional emails through Mailgun with an aggregate 95.43% delivery rate. Individual client level performance breaks down as follows.

Competition operator	Emails sent (Jul 2026)	Delivery rate	Bounce rate
LR Luxe Competitions	5,644	99.96%	0.01%
Luxora Draws	554	100%	0%
Cars and Kettles Competition	222	97.76%	0%
Pennies Win Pounds	55	100%	0%
Nera Marketing (transactional notifications)	39	100%	0%
Teescomps	25	100%	0%
Be The Ray Competitions	15	100%	0%

LR Luxe Competitions is the strongest single proof point in the fleet. Across 5,644 transactional emails in July 2026, delivery hit 99.96% with a 0.01% bounce rate. That level of performance is achievable for any UK competition operator using the transactional stack described above, with SPF, DKIM, and DMARC records aligned on the sending subdomain and a properly warmed domain reputation.

The pattern across the Nera Marketing client fleet is consistent. Client domains that have been sending for more than 30 days with correct DNS alignment consistently hit 97 to 100% delivery. Newer client domains occasionally drop into the 60 to 70% range for the first three to four weeks while sender reputation stabilises with the mailbox providers. That is normal, expected, and correctable with a proper warm up schedule.

For context on what those numbers mean in practice:

• 99%+ delivery rate means out of every 100 ticket confirmation emails sent, 99 reach the inbox. The industry “good sender” benchmark is around 95% delivery. Below 90% is considered a deliverability problem that needs immediate attention.
• 0% complaint rate means no recipients are marking the operator’s emails as spam. Sustained complaint rates above 0.1% will damage sender reputation. Above 0.3% will get the sending domain blacklisted by major email providers.
• 0% bounce rate means the recipient list is clean and the operator is not sending to invalid addresses. Sustained bounce rates above 2% indicate list hygiene problems that need to be addressed.

These outcomes are achievable for any UK competition operator using the Mailgun plus FluentSMTP plus dedicated subdomain stack with correct DNS configuration. They are not unique to one operator. They are the predictable result of getting the transactional setup right from launch rather than trying to fix deliverability after problems appear.

Common deliverability mistakes that kill competition operator email

The deliverability failures we see across UK competition operators consistently come from the same six configuration mistakes, each of which is preventable with the correct setup from day one. Operators experiencing inbox placement problems should audit their setup against this list before assuming they need a new email provider.

Since February 2024, both Google and Yahoo enforce bulk sender requirements that competition operators must comply with. These requirements are also documented in the Yahoo Postmaster guidance. Both require SPF, DKIM, and DMARC alignment for any sender pushing more than 5,000 emails per day. Competition operators regularly exceed this threshold during instant win draws and winner announcement waves. Non-aligned senders now see their emails silently deferred or filtered to spam without warning.

The DMARC.org specification defines the alignment requirements in detail. What matters operationally for a UK competition operator: the domain in your “From” address must match the domain that signs the DKIM and passes SPF. Getting this wrong is the single most common reason competition emails hit spam despite technically having SPF and DKIM records.

The six mistakes:

• Mistake 1: Using the default WordPress PHP mail. Without FluentSMTP or an equivalent SMTP plugin, WordPress sends email through the PHP mail function with no authentication, no IP reputation, and no deliverability tooling. Almost everything sent this way goes to spam. Install FluentSMTP and connect to a specialist provider before sending a single transactional email at scale.
• Mistake 2: Sending transactional through Klaviyo or marketing platforms. Covered above. Klaviyo is a marketing tool, not a transactional sender. Ticket confirmations through Klaviyo land in spam at a much higher rate than through Mailgun or Postmark, and any complaint contamination damages reputation across both channels.
• Mistake 3: Sending from the main domain. Every competition operator that sends from their main domain instead of a dedicated subdomain eventually has a deliverability issue that damages the main domain’s reputation. Use a subdomain from the start.
• Mistake 4: Missing or misconfigured DKIM and SPF records. Without proper authentication, Gmail and Outlook will increasingly send emails to spam regardless of content quality. SPF, DKIM, and DMARC are not optional. They are the minimum baseline.
• Mistake 5: Sending ticket confirmations with promotional content. A confirmation email that also contains marketing offers, upsells, or cross-promotion mixes transactional and marketing content. Email providers detect this pattern and treat the entire email as marketing for deliverability scoring, lowering inbox placement.
• Mistake 6: Ignoring bounce and complaint signals. Mailgun (and equivalent providers) provide detailed logs of failed sends, bounces, and complaints through the FluentSMTP dashboard or the provider’s own interface. Operators who do not monitor these signals miss the early warning indicators of deliverability decline and only notice when sales drop because customers stopped receiving confirmation emails.

Email deliverability for UK competition websites is not a one-time setup that runs itself. It is operational infrastructure that needs the right stack, the correct DNS configuration, strict separation of transactional from marketing, and ongoing monitoring of the signals the platform provides. For operators on Nera builds, this is configured before launch and monitored on an ongoing basis as part of the platform service. For operators handling it themselves, the choices in this guide are the starting points that consistently produce 99%+ inbox delivery for competition transactional email at scale.