If your business makes outbound sales or marketing calls, checking telephone numbers against the Telephone Preference Service (TPS) and Corporate Telephone Preference Service (CTPS) should be an essential part of your daily operations.
Whether your team makes 20 calls a day or several thousand, contacting a number registered with the TPS or CTPS without the necessary permission could put your business at risk of regulatory action, substantial fines and reputational damage.
The good news is that checking telephone numbers doesn’t have to be complicated, expensive or time-consuming.
Modern TPS checking software and API integrations allow businesses to check numbers automatically, including directly from their CRM systems and telephone diallers, before a call is connected.
At Selectabase, we provide three straightforward ways to check telephone numbers, with flexible packages starting from just £29 and solutions capable of handling millions of checks every year.
In this guide, we’ll explain what a TPS checking API is, how it works, why TPS and CTPS screening matters, and how your business can use our EasyCheck service to make telephone compliance easier.
What Is the Telephone Preference Service (TPS)?
The Telephone Preference Service (TPS) is the UK’s official register of telephone numbers belonging to individuals who have indicated that they do not wish to receive unsolicited live marketing calls.
People can register their landline or mobile telephone numbers free of charge.
Once a number has been registered for 28 days, businesses must not make unsolicited live direct marketing calls to that number unless the subscriber has specifically agreed to receive those calls from the particular business.
The Corporate Telephone Preference Service (CTPS) provides similar protection for companies and other corporate organisations that do not wish to receive unsolicited marketing calls.
An important distinction is that both registers can apply to business-to-business marketing.
For example:
- TPS – Covers individuals, sole traders and certain partnerships.
- CTPS – Covers limited companies, limited liability partnerships and other corporate organisations.
This means a business selling products or services to other businesses may need to check against both the TPS and CTPS registers, not simply one or the other.
The UK’s Information Commissioner’s Office (ICO) provides detailed guidance on telephone marketing and the rules surrounding TPS and CTPS.
What Is a TPS Checking API?
A TPS checking API (Application Programming Interface) is a technology that allows businesses to connect their existing software directly to a telephone number screening service.
Rather than manually uploading telephone numbers or checking them individually, an API enables your systems to perform checks automatically.
For example, a company using a CRM system such as Salesforce, HubSpot or another customer management platform could integrate a TPS checking API into its existing telephone calling process, subject to the platform’s integration capabilities.
When a salesperson selects a number to call, the API can automatically check that number against the TPS and CTPS registers before allowing the call to proceed.
This removes the need for staff to perform separate manual checks and helps businesses incorporate compliance directly into their existing workflows.
How Does a TPS Checking API Work?
Selectabase offers an EasyCheck API that allows businesses to screen telephone numbers against our daily-updated TPS and CTPS data.
A typical integration works as follows:
Step 1 – A salesperson selects a telephone number
A member of your sales team selects a prospect or customer from your CRM system and clicks the telephone number to initiate a call.
Step 2 – The API checks the number automatically
Before the call is connected, the telephone number is passed through the Selectabase EasyCheck API and checked against the relevant TPS and CTPS registers.
Step 3 – The system receives a result
The API returns a result identifying whether the telephone number matches a TPS or CTPS registration.
Step 4 – Your software decides what happens next
Depending on how your system has been configured, it can:
- Allow the call to proceed automatically when there is no TPS or CTPS match, provided your other compliance conditions are satisfied.
- Prevent a call from proceeding when a registered number is identified.
- Display a warning message informing the salesperson that the number is TPS or CTPS registered.
- Allow an authorised user to review the number and confirm whether the business has a valid reason to proceed.
Step 5 – The call is connected or cancelled
If a number is not registered and there are no other restrictions, the call can proceed as normal.
Where a number is registered, the salesperson can cancel the call or, if the business has documented evidence that the subscriber specifically agreed to its live marketing calls, proceed in accordance with its compliance procedures.
Important: Simply having an existing customer relationship does not automatically give a business permission to make marketing calls to a TPS or CTPS registered number. A relevant, specific agreement must exist. A warning override should only be used where that agreement has been verified.
By integrating these checks into the calling process, businesses can reduce the risk of staff accidentally contacting protected numbers.
Three Ways to Check TPS and CTPS Numbers with Selectabase
Not every business needs an API.
Some organisations only check a few numbers each day, while others need to screen thousands of records or integrate checks across an entire sales operation.
That’s why Selectabase offers three different ways to access its EasyCheck TPS and CTPS screening service.
1. Online TPS and CTPS Checker – Quick and Easy Screening
Our web-based TPS checking service is ideal for businesses that want a straightforward way to check telephone numbers without installing any additional software.
Simply access the checker through your web browser, enter the telephone numbers you want to screen, and review your results.
You can check individual numbers or screen larger batches of numbers in seconds.
The online checker is particularly useful for:
- Small businesses making occasional sales calls.
- Salespeople wanting to check a number before contacting a prospect.
- Telemarketing teams screening new calling lists.
- Businesses purchasing third-party marketing data.
- Organisations wanting to check telephone numbers without integrating software.
You can check up to 50,000 telephone numbers in a single batch using the online service.
There’s no need to invest in complicated software or expensive annual screening licences.
Explore the Selectabase Online TPS and CTPS Checker
2. Windows TPS Checking App – Screen Your Spreadsheets Directly
If your team regularly works with Microsoft Excel or CSV spreadsheets, our Windows EasyCheck application provides another convenient option.
Rather than copying and pasting lists into a website, you can open your calling data and check telephone numbers directly from your desktop.
The software can automatically identify telephone numbers that match the TPS or CTPS registers and flag the results within your spreadsheet.
You can choose how matching records are highlighted, including adding a TPS or CTPS flag, changing cell colours or marking numbers so your calling team knows they should not be contacted without the necessary permission.
The Windows application is ideal for:
- Businesses managing regular telephone marketing campaigns.
- Sales teams working from Excel spreadsheets.
- Companies purchasing or maintaining their own prospect databases.
- Telemarketing agencies preparing client calling files.
- Businesses wanting a simple way to update existing calling lists.
It’s particularly helpful for teams that want to retain their existing spreadsheet-based workflow while adding an extra level of compliance checking.
3. TPS Checking API – Automated Screening for CRM Systems and Diallers
For businesses making regular or high volumes of outbound calls, API integration is often the most practical solution.
Our TPS checking API allows developers and software providers to integrate the EasyCheck service into existing systems, including CRM platforms, telephone diallers and bespoke business software.
Rather than requiring staff to remember to check numbers, your system can automatically perform a check as part of the call initiation process.
The results can then be used to determine whether the call should proceed or whether a warning should be presented to the user.
The API is particularly suited to:
- High-volume outbound sales teams.
- Contact centres and telemarketing businesses.
- Companies operating integrated telephone dialling systems.
- CRM software developers.
- Businesses with multiple sales teams or offices.
- Organisations that want an automated, consistent screening process.
The main advantage is that TPS and CTPS compliance checks become part of the calling process rather than an additional task for staff to complete.
For companies processing thousands or millions of telephone numbers each year, this can save considerable time and reduce the risk of human error.
To request our API integration documentation and free test credits, email [email protected].
Why Do Businesses Legally Need to Check Telephone Numbers Before Calling?
Telephone marketing in the UK is regulated by the Privacy and Electronic Communications Regulations 2003 (PECR), alongside relevant requirements of the UK General Data Protection Regulation (UK GDPR) and Data Protection Act 2018.
PECR sets out specific rules governing direct marketing by telephone, email, text message and other electronic communication methods.
For most unsolicited live telephone marketing calls, businesses must ensure that:
- The telephone number is not registered with the TPS or CTPS, unless the subscriber has specifically agreed to receive their calls.
- The person or business has not previously asked them to stop making marketing calls.
- They identify their organisation when making the call.
- Their telephone number, or a valid alternative contact number, is displayed.
- They provide appropriate contact details if requested.
Businesses processing personal data must also meet applicable UK GDPR requirements, including having a valid lawful basis for processing personal information and respecting individuals’ rights.
In some circumstances, legitimate interests may be an appropriate lawful basis for live telephone marketing. However, this does not override the restrictions imposed by PECR or an individual’s objection to direct marketing.
There are also stricter rules covering certain categories of marketing, including claims management services and pension-related marketing.
Automated marketing calls that play recorded messages are subject to separate requirements and generally need specific consent.
Does TPS Checking Apply to B2B Telemarketing?
Yes.
One of the most common misconceptions is that TPS screening only applies to businesses making calls to consumers.
In reality, businesses making B2B marketing calls also need to comply with the relevant regulations.
For example, a company contacting local tradespeople might be calling sole traders whose numbers are registered with the TPS.
Similarly, a business contacting limited companies could be calling telephone numbers registered with the CTPS.
This makes checking both registers particularly important when working with business telephone databases.
The ICO specifically advises businesses making live B2B marketing calls to screen against both registers and their own internal do-not-call lists.
Can You Call an Existing Customer Who Is Registered with TPS?
Potentially, but only where the relevant legal conditions are met.
Being an existing customer is not, by itself, sufficient permission to make unsolicited marketing calls to a TPS-registered number.
Under PECR, the subscriber must have specifically notified your business that they do not object to receiving its live marketing calls.
For example, a customer who actively agrees to receive marketing telephone calls from your company may be contacted even if their number appears on the TPS register, provided that agreement remains valid and the other applicable rules are satisfied.
However, a customer who has simply purchased something previously, or who has never explicitly opted out, has not necessarily given permission.
Businesses should therefore maintain appropriate records showing when and how customers agreed to receive marketing calls.
This is why allowing an authorised user to review a TPS warning can be valuable, provided the business has clear procedures and evidence to support any decision to proceed.
What Are the ICO Fines for Calling TPS or CTPS Registered Numbers?
The financial consequences of failing to comply with telephone marketing regulations have become significantly more serious.
Historically, the maximum monetary penalty for breaches of PECR was £500,000.
However, the Data (Use and Access) Act 2025 introduced substantial changes to the ICO’s enforcement powers, with the new PECR penalty regime taking effect on 5 February 2026.
For qualifying serious breaches, the ICO can now impose fines of up to:
£17.5 million or 4% of an organisation’s annual worldwide turnover, whichever is higher.
The penalty awarded in any individual case will depend on the circumstances and the applicable legal requirements. This is a maximum, not an automatic fine for every breach.
These increased powers highlight why businesses should take telephone marketing compliance seriously.
And enforcement is not just a theoretical risk.
Examples of ICO Enforcement Action
In May 2026, the ICO announced a £160,000 fine against Energy Prices Direct Limited after the company made more than 700,000 unsolicited marketing calls to numbers registered with the TPS and CTPS.
In August 2026, the ICO also announced a £190,000 fine against Elderly Aids Ltd, following 758,053 unsolicited direct marketing calls to TPS-registered telephone numbers.
These cases demonstrate that organisations making high volumes of outbound calls can face substantial financial penalties when they fail to respect telephone marketing preferences.
Beyond financial penalties, organisations may also face investigations, operational disruption, customer complaints and damage to their reputation.
Businesses can read more about these enforcement cases directly through the ICO’s published announcements.
How Often Should Businesses Check Their Telephone Numbers?
A common mistake is to assume that a telephone database only needs to be checked once.
For example, a company might purchase a list of 10,000 business telephone numbers, screen them against the TPS and CTPS, and then continue using the same list for several months.
The problem is that telephone preferences can change.
A number that was not registered when a list was originally checked may subsequently be added to the TPS or CTPS.
Both registers are updated regularly, and registrations become effective after 28 days.
For this reason, the ICO advises businesses using third-party calling lists to ensure checks have been carried out recently.
A practical approach is to screen numbers as close as possible to the time they will be used.
For businesses running continuous outbound calling campaigns, API integration provides a particularly effective solution because numbers can be checked immediately before dialling.
Selectabase uses daily-updated TPS and CTPS data to help businesses access current registration information.
This reduces reliance on old screening results or manually maintained spreadsheets.
What Are the Benefits of Using a TPS Checking API?
For many organisations, the biggest advantage of an API isn’t simply that it checks telephone numbers.
It’s that the checking process can happen automatically, without interrupting the work of the sales team.
1. Reduce the Risk of Non-Compliance
Checking numbers against the TPS and CTPS before making marketing calls helps businesses avoid contacting registered numbers without the required permission.
While TPS screening alone does not guarantee full legal compliance, it is an important part of a responsible telephone marketing process.
2. Save Your Sales Team Time
Salespeople should be spending their time speaking to suitable prospects, not manually checking telephone numbers throughout the day.
By integrating screening into your CRM or dialler, checks can take place automatically as calls are initiated.
3. Reduce Human Error
Even well-trained employees can occasionally forget to complete a manual check.
An automated workflow reduces reliance on individual staff remembering every compliance step.
4. Improve Calling Data Quality
Screening your calling lists helps identify numbers that should be excluded from unsolicited telephone marketing campaigns.
This allows teams to focus their efforts on numbers that are not registered, subject to other applicable restrictions and the company’s own suppression records.
5. Make Compliance Easier to Manage
A properly configured integration can help businesses maintain a more consistent approach to telephone screening across different employees, departments and offices.
Where supported by the calling software, organisations can also maintain records of screening results, decisions and permissions.
6. Scale Without Complicating Your Processes
Whether you employ two salespeople or operate a large contact centre, an API-based approach can support increasing call volumes without requiring the same increase in manual screening work.
How Much Does TPS and CTPS Checking Cost?
One of the reasons some businesses avoid regular telephone screening is the assumption that it must involve expensive software, complicated licences or long-term contracts.
At Selectabase, we’ve designed our EasyCheck service to make TPS and CTPS checking affordable and accessible to businesses of all sizes.
Our prepaid checking packages start from just £29 for 2,000 checks, with larger allowances available for organisations processing tens of thousands or even millions of telephone numbers.
| Prepaid checking allowance | Price |
| 2,000 checks | £29 |
| 5,000 checks | £49 |
| 10,000 checks | £79 |
| 25,000 checks | £149 |
| 50,000 checks | £199 |
| 100,000 checks | £249 |
| 1,000,000 checks | £899 |
| 5,000,000 checks | £2,399 |
Each register checked uses a credit, so screening a number against both TPS and CTPS uses two checks.
Once your account is active, you can use the available checking methods, including the online checker, Windows application and API.
For organisations with more specialised requirements, our team can help identify the most appropriate checking allowance and integration approach.
View Selectabase TPS and CTPS Checking Packages
TPS Checking API – Frequently Asked Questions
Can I integrate TPS checking directly into my CRM?
Yes. The Selectabase EasyCheck API can be integrated into compatible CRM systems, telephone diallers and bespoke software through development work. This allows telephone numbers to be checked automatically before calls proceed, depending on how your integration is configured.
Does the TPS checking API check both TPS and CTPS?
Yes. The EasyCheck API supports screening against the TPS register, the CTPS register or both, depending on your requirements.
Can an API stop a salesperson calling a TPS-registered number?
Yes, where your calling system supports the appropriate integration. Your developer can configure the software to block the call, display a warning or require an authorised decision before proceeding.
Do I still need to check TPS if I have an existing customer database?
Yes, unless you have a valid basis for calling the registered numbers under the applicable rules. An existing customer relationship alone does not override TPS or CTPS registration.
Can I check thousands of numbers without using an API?
Absolutely. Our online checker and Windows application allow businesses to check numbers in batches without developing a bespoke integration.
Does TPS screening make my business fully GDPR compliant?
Not on its own. TPS and CTPS checking helps businesses meet specific telephone marketing requirements under PECR, but you must also comply with other applicable legal obligations, including UK GDPR requirements and your own do-not-call records.
Can I try the TPS checking service before purchasing?
Yes. Selectabase offers free introductory checking credits so businesses can try EasyCheck before committing to a paid package. If you’re considering API integration, our team can also provide the relevant technical documentation and discuss free test credits.
Make TPS and CTPS Checking Part of Your Everyday Calling Process
Telephone marketing remains an important way for businesses to generate enquiries, speak to potential customers and develop new relationships.
However, businesses also have a responsibility to respect people’s marketing preferences and comply with the rules surrounding unsolicited telephone calls.
Whether you’re making a handful of calls each week or operating a contact centre processing millions of calls each year, checking telephone numbers should be a straightforward part of your operation.
With Selectabase EasyCheck, you can choose the method that suits your business:
- Web-based TPS checker – Ideal for individual numbers and batch screening.
- Windows TPS checking application – Check and flag telephone numbers directly within spreadsheets.
- TPS and CTPS checking API – Integrate real-time screening into compatible CRM platforms, telephone diallers and bespoke software.
With daily-updated checking data, flexible packages and pricing starting from just £29, we can help businesses of virtually any size introduce a more efficient telephone screening process.
Request Free TPS Checking Credits and API Integration Details
Interested in seeing how our TPS checking API could work with your existing CRM or telephone dialling system?
Our team can explain how the integration works, provide technical API documentation and arrange free test credits so you can explore the service before committing.
Email: [email protected]
Telephone: 01304 383838
Website: www.selectabase.co.uk/services/tps/
Selectabase – Making TPS and CTPS checking simple, affordable and accessible for UK businesses.
