> ## Documentation Index
> Fetch the complete documentation index at: https://docs.verbose.cx/llms.txt
> Use this file to discover all available pages before exploring further.

# Suppression & compliance

> Keep the right numbers off your sends, and stay compliant by default.

Two things protect your recipients and your sender reputation: the **automatic
opt-out** that always applies, and **suppression lists** you control. On top of
those, every send observes **quiet hours** and **frequency limits**.

## Opt-outs are automatic

A contact who replies **STOP** (or a standard opt-out keyword) is opted out
immediately and **never messaged again** — across every campaign and flow. You
don't manage this by hand, and no configuration can override it. HELP and other
standard keywords are handled too.

<Warning>
  Deleting a contact is **not** an opt-out. A deleted contact you later re-import
  can be messaged again. To stop contacting a number permanently, put it on a
  suppression list.
</Warning>

## Suppression lists

A **suppression list** is a set of phone numbers to keep off your sends for your
own reasons — do-not-contact requests, litigators, competitors, prior customers.

<Steps>
  <Step title="Create a list and add numbers">
    Create a suppression list and add numbers (E.164). You can keep several — e.g.
    a global DNC and a per-client list.
  </Step>

  <Step title="Attach it to a campaign">
    In the campaign builder's **Audience** step, tick the suppression lists to
    apply. Any recipient whose number is on a checked list is skipped — on top of
    the automatic opt-out.
  </Step>

  <Step title="Manage over time">
    Add or remove numbers as needed; removing a number lets campaigns that
    reference the list message it again.
  </Step>
</Steps>

## Quiet hours & frequency

* **Quiet hours** — sends respect a local-time window (the TCPA 8am–9pm floor is
  the *recipient's* local time). Where a contact's timezone is known it's used;
  otherwise your workspace policy applies. Configure your window in workspace
  settings.
* **Frequency limits** — optionally cap how often a contact is messaged (a
  minimum gap between sends and a maximum per rolling window), counted across
  **all** campaigns and flows so no single track can over-message someone.

Both default to off until you set a window/limit, and both **withhold** messages
rather than dropping them — a contact outside their window is sent later, not
skipped.

## US A2P (10DLC)

Sending A2P SMS in the US requires **brand and campaign registration** with the
carriers (10DLC). Register your brand, then your messaging use-case (campaign),
before you send at volume. See the 10DLC endpoints under
[API reference](/api-reference); registration is distinct from your sending
campaigns.

## Over the API & MCP

Manage suppression lists programmatically — [Suppression](/api-reference) — or in
natural language via the [MCP server](/mcp).