--- title: Learn how to use Verifiers description: How to use verifiers to filter out false positive results --- [Skip to content](https://support.parashift.io/verifiers#main-content) [Contact us](https://support.parashift.io/kb-tickets/new?hsLang=en) [Customer support portal](https://support.parashift.io/tickets-view?hsLang=en) [![parashift\_logo\_white-2](https://support.parashift.io/hs-fs/hubfs/parashift_logo_white-2.png?width=250&height=45&name=parashift_logo_white-2.png)](https://support.parashift.io/?hsLang=en) Open main navigation Close main navigation - [Contact us](https://support.parashift.io/kb-tickets/new) - [Customer support portal](https://support.parashift.io/tickets-view) How can we help you? - There are no suggestions because the search field is empty. 1. [Support Center](https://support.parashift.io/?hsLang=en) 2. [Configuration Guides](https://support.parashift.io/configuration-guides?hsLang=en) 3. [Document Type & Fields](https://support.parashift.io/configuration-guides?hsLang=en#document-type-fields) # Learn how to use Verifiers ## How to use verifiers to filter out false positive results. Verifiers are one of the rule-based validation approaches, which filter out the false-positives. These let the user narrow down extraction results by applying some additional logic and checks to the extraction results.The verifiers will be processed after the transformers.   | **Verifier** | **Description** | | --- | --- | | coords: Position Range | Rejects candidates which are not with the rectangle made of \`left\`, \`right\`, \`top\`, \`bottom\` coordinates, e.g. at the top half page. | | coords: Position Range Center | Rejects candidates whose centers are not with the rectangle made of \`left\`, \`right\`, \`top\`, \`bottom\` coordinates, e.g. at the top half page. | | image: aspect ratio | Restricts the results to a range of aspect ratio. | | key-value: Pair Orientation | Defintion of keywords, which should be found in the near (horizontaly or verticaly) of the candidate. | | number: Page Number | Checks whether a candidate is on the specified page. Candidates found on other pages are ignored. | | number: Value Range | Can only be used if the \`output\_data\_type\` is numeric (integer or float). Candidates with a value that is smaller than \`minimum value\` or larger than \`maximum\_value\` are rejected. | | page: Has Not Pattern | Page containing the specified \`pattern\` are rejected. | | page: Has Pattern | Pages containing the specified 'pattern' are allowed. | | page: Range | Checks whether a candidate is located within the specified page range. Candidates found outside the configured page range are ignored. | | pick\_nth | This verifier picks the n-th element of the sorted candidate list. | | string: Ends With | Candidates that do not end with the specific string are rejected. | | string: Has Not Pattern | Candidates containing the specified \`pattern\` are rejected. | | string: Has Pattern | Candidates that do not contain the specified \`pattern\` are rejected. | | string: Starts Not With | Skips candidates whose prediction value start with a specific string. | | string: Starts With | Candidates that do not start with the specific string are rejected. | | string: String Length | Rejects candidates that do not have the right number of "characters". | ### Verifier "coords: Position Range" Definition of coordinates, where the candidate have to be found. The verifier can restrict the result horizontally (left coordinate \[0..1\] (float) - right coordinate \[0..1\] (float)) and vertically (top coordinate \[0..1\] (float) - bottom coordinate \[0..1\] (float)). All values are defined in percent between 0 and 1, using a point as decimal. ![](https://t4784071.p.clickup-attachments.com/t4784071/a16d3117-299e-4bdc-ac0f-c780a3eadae7/grafik.png) | **Parameter** | **Description** | | --- | --- | | Left coordinate | Left coordinate of the rectangle (related to page width) 0 \<= value \<= 1 | | Right coordinate | Right coordinate of the rectangle (related to page width) 0 \<= value \<= 1 | | Top coordinate | Top coordinate of the rectangle (related to page height) 0 \<= value \<= 1 | | Bottom coordinate | Bottom coordinate of the rectangle (related to page height) 0 \<= value \<= 1 | ### Verifier "coords: Position Range Center" Definition of coordinates, where the center of the candidate have to be found. The verifier can restrict the result horizontally (left coordinate \[0..1\] (float) - right coordinate \[0..1\] (float)) and vertically (top coordinate \[0..1\] (float) - bottom coordinate \[0..1\] (float)). All values are defined in percent between 0 and 1, using a point as decimal.   ![](https://t4784071.p.clickup-attachments.com/t4784071/7954eca8-d171-4ceb-bc9d-0aac26384298/grafik.png)   | **Parameter** | **Description** | | --- | --- | | Left coordinate | Left coordinate of the rectangle (related to page width) 0 \<= value \<= 1 | | Right coordinate | Right coordinate of the rectangle (related to page width) 0 \<= value \<= 1 | | Top coordinate | Top coordinate of the rectangle (related to page height) 0 \<= value \<= 1 | | Bottom coordinate | Bottom coordinate of the rectangle (related to page height) 0 \<= value \<= 1 | ### Verifier "key-value: Pair Orientation" Definition of keywords, which should be found in the near (horizontaly or verticaly) of the candidate.     ### Verifier "image: Aspect ratio" Check the aspect ratio of the result tokens (length / height). ![](https://support.parashift.io/hs-fs/hubfs/undefined-Jan-06-2026-02-37-56-1937-PM.png?width=638&height=188&name=undefined-Jan-06-2026-02-37-56-1937-PM.png) ![](https://support.parashift.io/hs-fs/hubfs/undefined-Jan-06-2026-02-37-56-4240-PM.png?width=332&height=358&name=undefined-Jan-06-2026-02-37-56-4240-PM.png)   - [Getting Started](https://support.parashift.io/getting-started?hsLang=en) - [User Guides](https://support.parashift.io/user-guides?hsLang=en#main-content) - [General](https://support.parashift.io/user-guides?hsLang=en#general) - [Validation](https://support.parashift.io/user-guides?hsLang=en#validation) - [Platform Workshops](https://support.parashift.io/user-guides?hsLang=en#platform-workshops) - [Configuration Guides](https://support.parashift.io/configuration-guides?hsLang=en#main-content) - [Document Type & Fields](https://support.parashift.io/configuration-guides?hsLang=en#document-type-fields) - [Automation](https://support.parashift.io/configuration-guides?hsLang=en#automation) - [Tenant (User management)](https://support.parashift.io/configuration-guides?hsLang=en#tenant-user-management) - [Workflow (Upload Configuration, Separation, Classification)](https://support.parashift.io/configuration-guides?hsLang=en#workflow-upload-configuration-separation-classification) - [Release Notes](https://support.parashift.io/release-notes?hsLang=en) - [API Documentation](https://support.parashift.io/api-documentation?hsLang=en#main-content) - [Platform API Configuration](https://support.parashift.io/api-documentation?hsLang=en#platform-api-configuration) - [Technical API Documentation](https://support.parashift.io/api-documentation?hsLang=en#technical-api-documentation) - [Professional Services](https://support.parashift.io/professional-services?hsLang=en#main-content) - [Project-based Service Packages](https://support.parashift.io/professional-services?hsLang=en#project-based-service-packages) - [Subscription-based Service Packages](https://support.parashift.io/professional-services?hsLang=en#subscription-based-service-packages) [![Knowledge Base Home](https://support.parashift.io/hubfs/parashift_logo_black-2.svg "Knowledge Base Home")](https://support.parashift.io/?hsLang=en) [Platform Live Status](https://status.parashift.io/)   |   [API Documentation](https://docs.parashift.io/) [mailto:support@parashift.io](mailto:support@parashift.io) Copyright © 2025, Parashift AG