---
title: "Upload your own suppression list"
description: "Stop WhoLayer from returning or sending you existing customers, employees, or anyone on your do-not-contact list."
url: https://wholayer.com/help/your-suppression-list
---

# Upload your own suppression list

> Stop WhoLayer from returning or sending you existing customers, employees, or anyone on your do-not-contact list.

Category: Privacy and compliance

Your suppression list applies to your workspace only, on top of our global opt-out list.

## Add people
- **Dashboard:** go to **Settings, Suppression list**. Paste emails or SHA-256 hashes, or upload a CSV or text file. We pick out every email address or 64-character hash and ignore other columns. Up to 100,000 people per upload.
- **API:** `POST /v1/suppression` with `{"emails": [...]}` and/or `{"email_sha256": [...]}`, up to 10,000 per request. Read-only keys can't add. `GET /v1/suppression/count` returns the size of your list.
- **MCP:** the `add_to_suppression` tool does the same.

Emails are trimmed and lowercased, then hashed with SHA-256. We store only the hashes. Dashboard uploads are hashed in your browser. A list holds up to 1,000,000 people.

## What changes
- Listed people are never identified at person level on your sites. Their visits still count at company level.
- They're never sent to Slack, Teams, webhooks, your CRM, or Klaviyo, and never shown in your People list or CSV export.
- The API and MCP server never return or charge for them: you get `451 person_not_available` with reason `customer_suppressed`.

## Remove people
Owners and admins can download the list as hashes or remove the whole list in **Settings, Suppression list**. Members can see the count and download it. Removing single entries isn't available yet.

## Related

- [How opt-outs and suppression work](https://wholayer.com/help/how-suppression-works.md)
- [API error codes and what to do](https://wholayer.com/help/api-errors.md)
- [Your responsibilities when you use WhoLayer](https://wholayer.com/help/customer-obligations.md)