A planned validation turns a dispersed base into more profitable, secure, and relevant campaigns for Black Friday 2026.
- Centralize contacts, purchases, and interactions. Preserve the origin of each piece of information and use trusted identifiers to join records without creating erroneous profiles.
- Clean up forms, remove duplicates, and preserve unsubscribes. A valid piece of information does not authorize sending: it requires explicit permissions per channel.
- Verify emails and phone numbers, separate invalid, temporary, and uncertain ones, and exclude pending ones from the first send to protect deliverability.
- Segment eligible contacts based on purchases, clicks, and interests. Adjust each offer to the profile and margin to avoid unnecessary discounts.
- Test links and personalization, send in batches, and pause for bounces or complaints. Measure sales and margin against a control group.
Validating data before Black Friday can decide whether your campaign reaches real customers or ends up in the spam folder. More than 30% of email addresses become invalid within a year, and a few spam traps can reduce deliverability by more than 40%.
In this guide, you’ll see what validating data means and what it’s for, how to do it in Excel, and how to verify emails and validate phone numbers for your database before Black Friday. We recommend cleaning, segmenting, and testing your database before launching any mailings.
Step 1: Prepare your data for Black Friday 2026
Before cleaning or checking records, gather all the information in a single workplace. With centralized data, you can validate each record with a stable criterion and prepare Black Friday 2026 campaigns that respond to purchases and the real interest of each contact.
What does validating data mean and what is it for?
Validating data means checking whether each record is complete, has a consistent format, and fits the intended use of it. For example, an email with an incomplete address cannot be included in the same group as a correctly written email. Similarly, a common unformatted purchase date also does not allow you to sort customers by recency.
Validating data is used to turn a dispersed base into a useful source for segmentation and planning. This review covers the personal data you need to communicate, purchase data, and interaction signals collected in your store and on your website.
Define what you’ll use each field for during the campaign first. Don’t mix goals:
- Identify the contact: name, email, telephone number and internal identifier.
- Recognise their relationship with the store: date of registration, orders, amount spent and categories purchased.
- Adapt the message: clicks, pages visited, products saved and interests declared.
- Manage shipping: contact permission, unsubscribe date and authorised channel.
With this structure, validating data is no longer a generic task. You will review each value according to a specific purpose. For example, you don’t need the phone number for an email, but you do need it for a message campaign if that channel is part of your planning.
Also write down the origin of each piece of information. Distinguish between web forms, store orders, customer service records, and subscriptions. Knowing the origin makes it easier to detect fields that are filled in differently or that arrive incomplete.
Gather contacts and purchases from your store and website
Export contacts from the systems you use and create a separate working copy of the original file. Gather, along with identification data, purchases made and behavior available on the web. Keep a column indicating the source of each record to preserve context.
Start with a simple inventory. You can use a sheet with the file name, the date it was extracted, the fields included, and the person responsible for reviewing it. This control avoids working with old exports when sales volume increases.
Unify the information through an identifier. Email is usually used to relate forms and orders, while a customer code allows you to solve cases in which the same person has used different addresses. If you do not have a reliable identifier, mark the record for later review instead of joining it by name coincidences.
Include the data that allows you to decide what you will show during Black Friday: last purchase, number of orders, accumulated spend, category purchased and activity on the website. Those who have bought accessories can receive a related offer, while those who have only visited one category will require a different message.
Verifying emails and validating phones will make more sense when each piece of information is already associated with an orderly record. It’s not enough to check an address; you need to relate the contact to their history.
Set review deadlines by November
27 Divide the work into internal dates and assign a manager to each block. Black Friday 2026 falls on November 27, so you should close the review with enough margin to create segments, test messages, and fix issues.
You can organize the calendar like this:
- First review: export contacts, orders, and web activity; locate empty fields and repeated sources.
- Technical review: prepare rules to validate data in Excel, unify formats, and separate pending records.
- Channel review: prepare files to validate phones and check email addresses.
- Operational closure: deliver a revised database to the team that will segment and schedule shipments.
Reserve time between phases to resolve records that require confirmation. Don’t wait until the day before to gather files or request access. With the data already centralized, the next step will be to clean up the database, set mandatory fields, and eliminate duplications.
Step 2: Clean and tidy up your contact
base A tidy database will allow you to review each record without altering the original information. After centralizing the files, apply uniform criteria before moving on to verifying emails or validating phone numbers.
Save a copy and define required
fields Create a working copy with the date in the file name and keep the original unchanged. This allows you to compare results, retrieve values deleted by mistake, and repeat a rule if you need to adjust it.
Define which fields should be present in each contact. For your sendings, mark the identifier, email or phone number as mandatory depending on the channel, and the status of the permission. Purchase and preference data can be left as complementary fields.
Avoid filling in unknown values with text that looks like real data. If a piece of information is missing, leave the field empty and mark it for review. This decision makes it easier to validate personal data without confusing an absence of information with a confirmed value.
How to validate data in Excel with rules and lists?
Use rules that limit what each column supports. Drop-down lists help you keep identical options in fields such as authorized channel, contact status, or category.
For example, create a list of the states Apto, Pendiente and Excluir. Select the cells in that column and set data validation to only allow you to choose one of those values.
You can also create conditional lists. If a first cell is empty, a second list can remain empty; when you choose a value in the first cell, the second one shows the available options. To do this, apply a formula SI: the reference to the previous cell must be relative, while the range containing the options must use absolute references. Then, copy the ruler to the rest of the rows.
This method reduces writing variations and sorts out decisions that you’ll later use when segmenting. If you’re working with the list in Excel, you can also check emails from the sheet itself.
Unify formatting and eliminate duplicate
contacts Apply unique formatting before comparing records. Always write column names the same, keep dates in the same order, and remove excess spaces at the beginning or end of values.
Review contacts who share email, phone, or internal identifier. Keep a single file when the data corresponds to the same contact and gather the values you need for the campaign. If two people share a piece of information but can’t confirm that they are the same, leave the record marked for review. You can find more details in our guide to cleaning a database.
Remember that what it means to validate data also includes this consistency: a field will only be useful if it maintains the same formatting throughout the database.
Review sending permissions and keep unsubscribes
Separate records according to the channel that each person has authorized. A correct email and a phone with a valid format do not replace the contact’s choice of how they want to receive communications.
Keep the unsubscribed ones in your own list and keep them when updating the database. Don’t delete that history when importing new files; check that the excluded contacts are still outside the sending groups. With this cleaner list, the process of checking emails and phones will be much more straightforward.
Step 3: Verify emails and phone numbers
“It’s not just because resources are being wasted… but, above all, to keep our sender reputation in very good shape and, in the process, achieve better deliverability” — Rui Nunes, sendXmail
Cleaning up the database is necessary, but not enough. After sorting out forms and removing duplicates, it remains to check if the contact channels can receive each communication. This phase of validating personal data detects impossible addresses and telephone numbers that require correction before incorporating them into a sending segment.
Why choose a per-file or API verification tool?
Choose a tool that processes a file when you need to review many records together. If your store needs to check registrations in real time, opt for one that also offers an API. Export only the necessary columns, preserve the internal identifier, and receive one result per row. With VerificarEmails You can upload the list in a file (CSV, XLS, XLSX or TXT) or integrate the test on your website with your Email Validation API, without sending any emails to your contacts during the process. If you want to compare options, check out our Comparison of tools to verify emails.
Give the result a check-in date. This will distinguish a recent review from a pending one, and avoid treating both cases the same way when targeting for Black Friday 2026.
Check the format and domain of your emails
Confirm that each email contains a local part, the @ sign, and a domain. Then, check that the domain is written without spaces, duplicate periods, or transcription errors. These checks filter out visible flaws, but they don’t prove that the mailbox supports messages.
When verifying emails, mark manual edits so you can check their origin. Don’t replace an address with a deduction based on the contact’s name.
Distinguish invalid, temporary, and uncertain
emails Classify as invalid the email whose format or domain does not pass the check. Set aside temporary emails (disposable emails), created for brief uses, because they do not have a stable relationship with your brand. An uncertain status indicates that the tool has not confirmed or discarded the address. This is what happens, for example, with domains that accept any address (catch-all): VerifyEmails marks them as “inconclusive” so that you can decide what to do with them.
Remember that in the latter case, keep the record out of the initial submission and schedule a recheck. Don’t turn an incomplete technical response into a suitable result; doing so can negatively affect your sender reputation and increase the likelihood of being flagged as spam.
How to validate phone numbers for Black Friday
Save each number in international E.164 format (e.g. +34 and the number) and separate any extensions in a field of your own. Remove excess spaces, letters and signs that are not part of the stored data. Then, check the length and consistency with the country indicated by the contact themselves.
If a phone is repeated on different cards, send it for review instead of automatically attributing it to a contact. Thus, phone validation produces a more reliable technical list and reduces errors in message sending.
If you are going to send SMS on Black Friday, the format is not enough. With the portability query (MNP) you know which operator each number is with today, and with the HLR query, if the line is active. This way you avoid paying for shipments to lines that are not operational. VerifyEmails offers both in its phone number validation service, by file or by API. We tell you step by step on how to verify phone numbers before your SMS campaign.
A valid contact does not guarantee permission or delivery
A positive check only indicates that the data passes the controls applied. The permission depends on the channel that the contact has authorized, and deliverability can also vary depending on each specific send. A few spam traps on the list are enough to damage your sender reputation. That’s why we recommend that you check ahead of time and don’t leave this phase for the days leading up to November 27.
Verify your database before November 27. With EmailVerify, you upload your email or phone list, download the result, and separate eligible contacts. You pay in euros, without a subscription, and you can start with trial credits. Check the prices for verifying emails and verifying phones.
Step 4: Use the results to create secure
segments With the technical and permission statuses already noted in each row, the next job is to convert that revised sheet into operational groups. This is where validating data makes its most practical sense within the campaign: deciding who receives each proposal, when they receive it, and which contacts are left out of the sending.
Separate eligible, pending, and excluded
contacts Work with three statuses. Eligible are those with a favorable verification result and authorization for the intended channel. Pending are grouped together cards with uncertain outcome or with business information that you have yet to complete. Excluded ones collect unsubscribes, invalid data, and records that should not participate in this action.
Label each group in a column separate from the original result. This way the criteria applied is documented and you can update a pending file without altering the rest. Also keep the date of the last revision; it will help you prioritize the oldest records in the next check.
Group customers by purchases, clicks, and interests
Sort eligible customers based on the relationship they already have with your store. You can combine purchases, clicks, and interests to differentiate between recent purchases, those who consult a category, and those who respond to certain content.
RFM segmentation organizes customers according to recency, frequency, and monetary value of purchase. For example, it brings together in one group those who show interest in a category without having purchased it and in another customers with related previous orders. Avoid mixing both profiles: the first communication may present the product, while the second may recognize a previous purchase. They are different messages for different times.
Define which offer each group will receive without losing margin
Before assigning discounts, review the margin per proposal. Reserve the most adjusted offers for groups with the highest purchase affinity and propose different incentives for those who have only clicked. This will measure which combination generates profitable sales without giving up margin where it is not needed.
Remember that a well-constructed segment is based on verified data. Without that base, not even the most careful message will reach where it should.
Step 5: Test your submissions and monitor your results
Review links, custom fields, and unsubscribes before sending
Before activating the commercial calendar, do a real test with each version of the message. Open it on desktop and mobile. Check that the links work, that the discount codes are correct, that the custom fields show the correct value, and that the unsubscribe link excludes the contact before scheduling the checkout. If any of these elements fail the test, it will also fail the final delivery.
Increase the volume gradually and avoid overcrowding
Start with a small portion of eligible contacts. When the indicators remain stable, expand in batches. This order allows you to detect an anomalous response before reaching the entire audience. Don’t throw the entire volume at once; a problem caught early is much easier to correct.
Keep an eye out for bounces, complaints, and delivery failures to pause in time
Record what’s happening in each batch: bounces, complaints, and delivery failures. If any of these signals go up, pause the next block. Review the affected segment and correct the message or settings before resuming. Remember that a high complaint rate can affect your entire sender reputation, not just the ongoing shipment.
Compare sales and margin with a control
group Reserve a portion of the eligible segment with no offer or a different variant. Then, compare sales, orders, and margin between the two groups. This will let you know if the incentive generates additional revenue and if it retains the expected return. Without that control group, you won’t be able to know how much of the result is due to the discount and how much would have happened anyway.
Conclusion
“The issue of data quality remains one of the biggest obstacles to effectively analyzing the customer perspective and journey. It also dramatically increases the costs of analytics projects and negatively impacts performance.” — Sameer Khan, senior director of product marketing and client analytics, IBM
Validating data before Black Friday 2026 helps you protect deliverability, respect permissions, and direct each offer to contacts with real interest. A clean, duplicate-free, and consistently formatted base makes it easy to verify emails and validate phone numbers without unnecessary errors.
Likewise, segmenting according to purchases, clicks and preferences allows you to adapt the message and take care of the margin of each promotion. Testing in batches and tracking bounces, complaints and sales complete the process.
In short, reviewing, confirming and measuring ahead of time makes your data more secure decisions. Maintain this routine and your campaigns will arrive better prepared at the key moment.
Frequently Asked Questions
What is the purpose of validating data before Black Friday 2026?
It allows you to detect incomplete records, errors, and duplicates to better segment contacts. It also helps to respect sending permissions and reduce delivery problems.
How do I validate my contact database in Excel?
Save a copy of the file, define required fields, and unify formats. Use validation rules and drop-down lists to maintain consistent statuses, such as pass, pending, and excluded.
How do you verify emails and phones before a campaign?
Review emails with a per-file verification tool or API. On phones, check the prefix, length, and consistency with the country indicated, and if you’re sending SMS, the current carrier (MNP) and whether the line is active (HLR). Leave uncertain results pending review.
Does a valid email mean I can send you promotions?
No. Technical validity does not replace permission to receive communications or guarantee delivery. Check channel authorization and keep unsubscribes out of submissions.
What should I check before launching Black Friday shipments?
Try links, discounts, custom fields, and the unsubscribe link. Start with a small group of eligible contacts and expand in batches; if bounces, complaints, or delivery failures increase, pause and review.
What tool can I use to verify emails and phones before Black Friday?
With VerifyEmails you verify emails and, in the phone validation service, you check the portability (MNP) and if the line is active (HLR). You can upload a file from the panel or use the API, you pay in euros without a subscription and the support is in Spanish.
