# Duplicate Prevention – Definition, FAQs & How Dedupely Helps > Duplicate prevention explained: how to prevent duplicate contacts from forms, imports and integrations, and why fast detection and merging cover the rest. - URL: https://dedupe.ly/glossary/duplicate-prevention - Section: glossary - Site index: https://dedupe.ly/llms.txt - Any page: append `.md` to its URL for this plain-text form --- [Glossary](https://dedupe.ly/glossary) Duplicate Prevention ## Duplicate Prevention Duplicate prevention is the practice of keeping new duplicate records out of a CRM as records arrive, by checking each new record against existing ones before or just after it's saved. It covers every way records come in: web forms, list imports, integrations and syncs, and reps adding contacts by hand. The checks take a few forms. An entry rule compares a new record with existing ones and warns, flags or stops the save. A form or integration looks up a unique value, such as an email address, and updates the matching record instead of creating a new one. An import check compares each row on a key field. Each of these depends on the fields it compares, and those are often only one or two, so a person entered with a second email or a typo in their name can still arrive as a new record. That's why duplicate prevention is often paired with fast detection and merging of the duplicates that get through. See how Dedupely merges new duplicates as soon as possible in your CRM [Try for free](https://v2.app.dedupe.ly/signup) [Talk to sales](https://meetings.dedupe.ly/meetings/gaby-salinas/talk-to-sales) Overview Duplicate prevention stops new duplicate records as they enter a CRM, through checks on forms, imports, integrations and records added by hand. Because those checks often compare only a few fields, it works best paired with a fast way to find and merge the duplicates that get through. On this page - What Is Duplicate Prevention? - How Duplicate Prevention Works - Why Duplicate Prevention Matters for CRM Teams - Getting Started With Duplicate Prevention - Key Takeaways: Duplicate Prevention - Frequently Asked Questions About Duplicate Prevention - Related Terms and Concepts See how Dedupely merges new duplicates as soon as possible in your CRM [Try for free](https://v2.app.dedupe.ly/signup) [Talk to sales](https://meetings.dedupe.ly/meetings/gaby-salinas/talk-to-sales) ### What Is Duplicate Prevention? Duplicate prevention, also called duplicate blocking, is the work of stopping duplicates at the points where records enter a CRM. It applies to every object that takes in new records: contacts and companies in HubSpot, leads and contacts in Salesforce, people and organizations in Pipedrive, leads in Close, and contacts in Nimble and Google Contacts. A simple example: Ana Ruiz from Acme is in the CRM as ana@acme.com. She fills out a web form with ana.ruiz@gmail.com, and the form looks up the email, finds no match and creates a new contact. A rep then adds "Anna Ruiz, Acme" from a call, with no email at all. Two checks on email let both records in, while a check that compared names loosely, along with company, would have caught them. There are three common approaches, and teams often combine them. Entry checks run when a record is created by hand and warn about, flag or stop a likely duplicate. Their strength is timing: the person entering the record can fix it on the spot. Lookup before create sends form fills, imports and integration records to an existing record when a unique value matches, and updates it instead of adding a new one. Its strength is that it works without anyone watching. Detect and merge after entry compares new records with existing ones soon after they arrive and merges the duplicates. Its strength is reach: it can compare several fields with looser methods, across every entry point at once. Resources: - [What is a duplicate?](https://dedupe.ly/blog/what-is-a-duplicate) ### How Duplicate Prevention Works Each approach follows the same basic path from a new record to a decision. - **A record arrives.** It comes from a form fill, an import, an integration or sync, an enrichment tool, or a rep typing it in. - **The key fields are read.** The check takes the values it compares, such as email address, phone number, company domain or a record ID from another system. A record with a blank key field often can't be checked at all. - **Existing records are searched.** The values are compared with records already in the CRM. Many entry checks compare values exactly, so a typo, a nickname or a phone number in another format makes the record look new. - **A decision is made.** Depending on the setup, the new record is blocked, saved with a warning or flag, routed to update the existing record, or saved as new. - **Records that get through are caught later.** A duplicate search that runs often, on more fields and looser methods, compares the newest records with the rest of the CRM. Clear duplicates are merged, and uncertain ones go to a person for review. The earlier a check runs, the less data it has to go on, since a form fill may hold only a name and an email. A check that runs soon after entry sees the full record and every other record it could match. That's why prevention at entry and fast matching after it often work as two halves of one process. Resources: - [Finding Duplicates](https://dedupe.ly/knowledge-base/find-duplicates) (KB) ### Why Duplicate Prevention Matters for CRM Teams A cleanup only holds if new duplicates stop arriving faster than they're removed. Forms, imports, integrations and reps all add records every day, and each one that duplicates an existing customer starts splitting that customer's data again. Without duplicate prevention, a CRM drifts back toward the state it was in before the last cleanup, and each cleanup has to start over. The cost of a duplicate grows the longer it stays. In its first minutes, a new duplicate holds little more than a form fill. Within days, it can have its own owner, lifecycle stage, emails, tasks and deals, so reports count the customer twice, two reps may work the same lead, and merging means sorting out two histories. In tools that bill by contact or record count, it's also a record paid for twice. Prevention that's too strict has costs too. A rule that blocks every record sharing a name or a company can stop real new contacts, and integrations that hit a block may fail quietly or retry, so the record never reaches the CRM at all. A setup that checks the clear cases at entry, and finds the rest soon after, keeps new records flowing while the time any duplicate stays in the CRM stays short. Resources: - [Why your CRM database is turning into a mess (and how to fix it)](https://dedupe.ly/blog/why-your-crm-database-is-turning-into-a-mess) ### Getting Started With Duplicate Prevention Start by mapping where new records come from. List each form, import routine, integration and sync, and check a sample of recent duplicates to see which entry points created them. The sources that create the most are the first to fix. Then set each entry point to recognize records it already has. Forms and integrations work best when they look up a unique value, such as email or an ID from the other system, and update the matching record. Imports work best on a cleaned file with the key column mapped. Keep entry rules on the strongest fields, so they stop clear duplicates without blocking real new records. Finally, plan for the duplicates that still get through. Run a trusted duplicate search often enough that new duplicates are merged before anyone works them, and send uncertain matches to a person. Clean the existing duplicates first, so each run only has to handle what's new. In Dedupely, new records are detected within 1–5 minutes, and Auto Merge can run a Duplicate Search you trust as soon as possible, merging new duplicates under your Primary Record and Merge Rules. It skips matches excluded by Safety Settings and sends low-confidence matches to Manual Review instead of merging them. Resources: - [Merging duplicates](https://dedupe.ly/knowledge-base/merge-duplicates) (KB) - [Syncing Records](https://dedupe.ly/knowledge-base/syncing-records-with-dedupely) (KB) ### Key Takeaways: Duplicate Prevention Duplicate prevention keeps new duplicates out of a CRM as records arrive from forms, imports, integrations and reps. Entry checks and lookups on a unique value stop many of them, but they often compare only a few fields, so records with a second email, a typo or a blank key field still get through. Pairing checks at entry with fast detection and merging keeps the time any duplicate stays in the CRM short. In Dedupely, new records are detected within 1–5 minutes. Auto Match and Auto Merge keep a trusted Duplicate Search running: Auto Match notifies you when new matches reach a count you set, and Auto Merge can merge new duplicates as soon as possible. Safety Settings hold risky matches back, and low-confidence matches go to Manual Review. Resources: - [Dedupely product overview](https://dedupe.ly/product) ### Frequently Asked Questions About Duplicate Prevention #### Can you stop duplicates at entry in a CRM? You can stop many of them at entry, but not all. Entry checks compare a new record with existing ones on the fields they watch, and warn, flag or block a likely duplicate. Forms and integrations can look up an email address or an external ID and update the matching record instead of adding a new one. The details differ by CRM and setup, whether that's HubSpot, Salesforce or Pipedrive. What entry checks can't see is a match on fields they don't compare: a second email address, a nickname, a phone number in another format or a blank key field. Those records arrive as new. In Dedupely, new records are detected within 1–5 minutes, and a Duplicate Search can compare several fields, each with its own Match Option, such as Exact, Similar or Fuzzy. With Auto Merge on that search, set to run as soon as possible, the duplicates that got past entry are merged soon after they arrive. #### Why do duplicates still appear when duplicate prevention is turned on? Because prevention only catches records that match on the fields it checks, and new duplicates often differ on exactly those fields. A contact who fills out a form with a personal email, after a rep added them with a work email, passes an email check. So does a company entered as "Acme Inc" when "Acme, Inc." already exists. Some entry points may not run the check at all, such as an integration that writes records directly or an import set to create new records only. Records with a blank email or ID can't be compared either. Checking a few recent duplicates shows which entry point and which field let them in. In Dedupely, a Duplicate Search on the affected object finds those records on the fields the entry check skipped. Auto Match notifies you when new matches reach a count you set, and Auto Merge can merge them on a schedule or as soon as possible. #### How do you prevent duplicates from integrations? Have each integration look up a unique value before it creates a record, and update the match instead of adding a new one. An email address works for contacts, a domain for companies, and an ID from the other system works best of all when both sides store it. Check what the integration does when a value is missing or in a different format, since that's where many integration duplicates start. When two systems sync both ways, make sure a merge in one doesn't recreate the record from the other. In Dedupely, new records from integrations are detected within 1–5 minutes, and Auto Merge can merge new duplicates as soon as possible. With an active HubSpot–Salesforce integration, Dedupely merges the duplicates in both CRMs at once, and Salesforce sync protection keeps a company linked to its Salesforce Account when companies merge. Outside that sync, each connected CRM is handled on its own. #### What's the difference between duplicate prevention and deduplication? Duplicate prevention stops new duplicates as records arrive, while deduplication finds and merges duplicates already in the CRM. Prevention works at the entry point, with checks on forms, imports, integrations and records added by hand. Deduplication works across the whole database, on the fields and match methods the search uses. The two overlap when deduplication runs often enough to catch new duplicates within minutes of entry, before anyone works them. Most CRMs need both: prevention lowers how many duplicates get in, and deduplication merges the existing backlog and the new duplicates prevention misses. Clean the backlog first, then keep both running. In Dedupely, Duplicate Searches and Bulk Merge clear the existing duplicates, and Merge Rules decide what each merge keeps. For new records, Auto Merge can run a trusted search as soon as possible, and Dedupely detects new records within 1–5 minutes. Merges can't be undone, so check a search's results before automating it. #### How do you prevent duplicate contacts from web forms? Set each form to match on email address and update the existing contact when the email matches, rather than creating a new one. Make the email field required, and check its format, so the form always has a value to compare. Hidden fields or tracking cookies can help a form recognize a returning visitor. Duplicates still come in when someone uses a different email, mistypes it, or fills out a form that writes to the CRM through an integration with its own rules. Check a few recent form contacts against older ones to see which forms create the most. In Dedupely, a Duplicate Search that combines name with company or phone finds form contacts who used a second email. New records are detected within 1–5 minutes, and Auto Merge can merge them as soon as possible. Blank values never win a merge, so an empty form field doesn't overwrite data on the existing contact. ### Related Terms and Concepts #### [Native deduplication](https://dedupe.ly/glossary/native-deduplication) Native deduplication is the duplicate checking built into a CRM. Its entry checks are the most common form of duplicate prevention, limited to the fields they compare. #### [CRM import](https://dedupe.ly/glossary/crm-import) A CRM import adds many records at once, which makes it one of the main entry points prevention has to cover. Cleaning the file first and checking after the import keep it from adding duplicates. #### [CRM sync](https://dedupe.ly/glossary/crm-sync) A CRM sync keeps records in step between two systems. It's a common source of new duplicates when the two sides don't recognize the same record. #### [Auto merge](https://dedupe.ly/glossary/auto-merge) Auto merge merges new duplicates on a schedule, which can run continuously. It handles the duplicates that get past checks at entry, soon after they arrive. #### [Ongoing deduplication](https://dedupe.ly/glossary/ongoing-deduplication) Ongoing deduplication runs duplicate searches continuously or on a schedule. Duplicate prevention lowers how many new duplicates it has to find. #### [Recurring duplicates](https://dedupe.ly/glossary/recurring-duplicates) Recurring duplicates are the ones that keep coming back after a cleanup. Tracing their causes shows which entry points need stronger prevention. Skip to content