BFCM Email Subject Lines: 30 Templates and a Test Method in Klaviyo

During Black Friday and Cyber Monday, an inbox receives dozens of promotional emails whose subject lines look like yours. Klaviyo's documentation does not quantify what one wording earns over another, and this article will quote no open rate. It does describe the qualities expected of a subject line, the elements worth testing and how to test them. That framework is used here to sort 30 wording templates by phase of the BFCM calendar, which you adapt to your offer and put to the test on your own audience.

TL;DR. Klaviyo asks for a subject line that is clear, concise and compelling, with a readable call to action, personalization where it makes sense, and urgency only when the message calls for it. The 30 templates below are grouped into six phases, from early access to the last day. To choose between them, Klaviyo's A/B test compares one variable at a time, preferably with two variations and open rate as the winning metric for a subject line.

Want an outside look before you write your sends? We offer a Q4 readiness audit: 30 minutes, free, no strings attached.

What Klaviyo's documentation asks of a subject line

The page on raising campaign open rates sums up the general rule: be clear, concise and compelling (Klaviyo, how to increase campaign open rates). It details three levers.

• A readable call to action. For a flash sale, the page advises making it obvious in the subject line and adding a sense of urgency. For news that requires a click, it asks you to be honest and informative and to cut unnecessary wording.
• Personalization. The recipient's first name, but also collected profile properties (local events, weather, interests) or hopes and pain points your audience shares.
• Urgency, when it applies. The page cites a time limit in the subject line, such as reward points that expire in two weeks or a sale that ends in 48 hours, and adds that it only makes sense for a message that fits, such as a flash sale or a VIP reminder.

For a BFCM, the last caveat carries weight. A weekend promotion has a real deadline, and that is the one case where urgency tells the truth. The same page recommends sending to engaged segments and choosing the send time in the recipient's local timezone: the subject line only does its job if it reaches the right person at the right moment. Our BFCM send calendar covers both points.

Klaviyo's accessibility page, for its part, asks for subject lines and preview text that are descriptive, enticing and short (Klaviyo, accessibility best practices).

30 subject line templates by calendar phase

Square brackets mark what you replace. These wordings are starting points we wrote ourselves: they do not come from the documentation, and we attribute no result to them.

Phase 1: early access (VIPs and waitlist)

1. Your early access is open: [offer] before everyone else
2. [First name], you go first this year
3. Waitlist: the sale starts for you right now
4. For our loyal customers only: [offer] until [time]
5. Private opening tonight: [category] at [discount]

These five subject lines address groups you built yourself, and the wording can say so plainly. Our guide to the Black Friday waitlist covers how to build the group.

Phase 2: public opening

1. Black Friday is open: [discount] on [category]
2. [Offer]: it starts now, until [date]
3. The whole store at [discount], starting now
4. The [number] deals not to miss this week
5. [Hero product] at [price]: Black Friday begins

Phase 3: reminder to people who did not open

1. You may have missed it: [offer]
2. Still here until [time]: [offer]
3. Last chance for [category] at [discount]
4. [First name], your selection is waiting
5. Only [duration] left to enjoy [offer]

Our article on BFCM audiences covers the eligibility and timing rules of a reminder, Smart Sending included.

Phase 4: the weekend

1. Saturday: [deal of the day] only
2. Two more days for [offer]
3. This week's best-sellers, still at [discount]
4. Your cart is part of the [discount] selection
5. What other customers picked yesterday

Phase 5: Cyber Monday

1. Cyber Monday: [offer] ends tonight
2. Monday only: [discount] on [category]
3. Final hours for [offer]
4. [First name], only [stock] left of [product]
5. The last Cyber Monday stock

A stock figure or an end time goes in only if the data is accurate at send time. The article on Cyber Monday strategy covers what to send when everything is already on sale.

Phase 6: extension and thank-you

1. Extended until [date]: [offer]
2. Thank you for your trust: [benefit] on your next order
3. The sale is over, your [benefit] stays valid until [date]
4. One day left to use your code [code]
5. Your order is on its way: here is what comes next

Template 27 and template 30 belong in a flow rather than a campaign. The last-week Klaviyo flows article covers where they fit.

Personalizing with the first name without breaking the line

For testing personalization in a subject line, Klaviyo cites the tag {{ first_name|default:'Friend' }} (Klaviyo, how to A/B test an email campaign). The part after default: is the fallback value, displayed when the profile has no first name. Pick a fallback that keeps the subject line readable. A line like "[First name], your selection is waiting" must still make sense when the fallback value replaces the name. If it does not, use a version of the line that does not need it for incomplete profiles.

Emojis: rendering changes by mailbox

Klaviyo supports all emojis in the subject line and in the drag-and-drop editor. The dedicated page warns that a character the recipient's email client does not support shows up as a box, and that the same emoji renders differently from one client to another. It recommends testing a new emoji by sending test campaigns to a preview list or with a tool such as Litmus. It adds that screen readers read emojis aloud (Klaviyo, emojis in subject lines and templates).

On a mass send like Black Friday, a test across a few mailboxes costs a few minutes and spares you the discovery of an empty box in the subject field on launch day.

Testing the subject line with Klaviyo's A/B test

The campaign A/B test page gives the rules that matter for a BFCM (Klaviyo, how to A/B test an email campaign).

• One variable at a time. If you edit the subject line, change nothing else. Klaviyo recommends keeping the test to two variations.
• The winning metric. For a subject line, open rate is recommended. Click rate suits a content test better, such as button size or color.
• Elements the page suggests testing for opens: statement versus question, subject line length, first-name personalization, emojis, preview text (present or absent), sender name, and day and time of sending.
• A test on a sample. In the page's example, 20% of recipients get variation A, 20% get variation B, and a winner is chosen after 6 hours for the rest of the audience. When the test size is below 100%, the test duration is adjustable.
• Generated variations. On paid accounts, Klaviyo can create a subject line test from prompts such as with or without personalization, short or long, question or statement, with or without an emoji.

Two caveats on the page are worth reading before a BFCM send. For Apple devices that use Mail Privacy Protection, open rates can be inflated. Klaviyo says it accounts for these opens in tests, but notes that a higher threshold may be needed to reach statistical significance, and suggests a custom report that includes an MPP property if more than roughly 45% of your opens come from Apple Mail. Our article on Apple Mail Privacy Protection explains the mechanism. Also, the option of personalized variations for each recipient is limited to accounts with more than 400,000 profiles; below that, Klaviyo applies the winning-variation test.

One scheduling point follows from these rules, and it comes from us rather than from the documentation. A sample-based test means waiting for the test period to end before the rest of the audience receives the winning variation. For a send tied to a specific time, such as an 8 a.m. opening, schedule the test early enough for the winner to go out at the intended hour. Our guide to A/B testing in Klaviyo covers the general method.

Klaviyo's subject line assistant

Klaviyo's subject line assistant offers three suggestions from the description you type in the subject line field, for a campaign or a flow email (Klaviyo, subject line assistant). The Regenerate button produces new proposals, and the page notes the field works best with full sentences: copying the description of a product or event from your site is one option. Suggestions can then be edited by hand. The page closes by advising you to A/B test a few options to learn which ones your audience prefers.

For a BFCM, the assistant is useful for producing starting variants, which you then review against the rules in the rest of this article: clear, honest about the deadline, suited to the phase.

Checklist before scheduling

1. Each subject line matches a calendar phase and a specific segment.
2. Deadlines, stock and discounts quoted are accurate at send time.
3. The fallback value of the first-name tag is set and the subject line stays readable with it.
4. Emojis have been tested across several mailboxes.
5. The A/B test changes one variable only, with two variations.
6. The test duration leaves time for the winning variation to go out on schedule.
7. The preview text extends the subject line instead of repeating it. Email copywriting frameworks help you write it.

FAQ

Should the first name always be in the subject line?

Klaviyo recommends it as a personalization option and suggests testing it in an A/B test. Its tag requires a fallback value for profiles without a first name, and the subject line must stay readable with it.

Can urgency go in every BFCM subject line?

The documentation reserves it for messages where it applies, such as a flash sale or a VIP reminder. A real promotion deadline is a typical case, an invented one is not.

How many variations should you test?

Klaviyo recommends two variations, with a single variable changed between them. For a subject line, the recommended winning metric is open rate.

Do emojis work everywhere?

Klaviyo supports them, but rendering depends on the recipient's email client, and an unsupported character shows up as a box. The page recommends testing them before sending.

Have the 30 templates been proven?

No: they are illustrative wordings we wrote, with no measured result. Only a test on your own audience shows what works for you.

Want an outside look at your BFCM sends? We run Q4 readiness audits, or you can talk to the Deliver team directly.