/vercel-firewall

name: vercel-firewall
description: Vercel Firewall expert guidance — automatic DDoS mitigation, the Vercel WAF (custom rules, IP blocking, managed rulesets, rate limiting), Attack Mode, system bypass, bot management, and the `vercel firewall` CLI. Use when configuring platform-level security, responding to attacks, or staging firewall rules.
metadata:
  priority: 7
  docs:
    - 'https://vercel.com/docs/vercel-firewall'
    - 'https://vercel.com/docs/cli/firewall'
  bashPatterns:
    - '\bvercel\s+firewall\b'
  promptSignals:
    phrases:
      - 'vercel firewall'
      - 'vercel waf'
      - 'attack mode'
      - 'ddos protection'
      - 'ip block'
      - 'managed ruleset'
      - 'bot protection'
      - 'system bypass'
      - 'rate limit rule'
    allOf:
      - [firewall, vercel]
      - [waf, vercel]
      - [ddos, vercel]
      - [challenge, vercel]
      - ['rate limit', vercel]
      - ['system bypass', vercel]
      - ['ip block', vercel]
    noneOf: []
    minScore: 6
retrieval:
  aliases:
    - ddos protection
    - waf rules
    - bot protection
    - rate limiting
    - attack mode
    - ip allowlist
    - traffic filtering
    - verified bots
  intents:
    - protect from ddos
    - block malicious traffic
    - configure firewall
    - rate limit api
    - allow bot through firewall
    - enable attack mode
    - publish firewall rule
  entities:
    - Vercel Firewall
    - Vercel WAF
    - DDoS
    - Attack Mode
    - Bot Protection
    - Managed Rulesets
    - System Bypass
    - JA3
    - JA4

Vercel Firewall

You are an expert in the Vercel Firewall including the `vercel firewall` CLI, Vercel WAF and platform-level protections (custom rules, IP blocks, system bypass, Attack Mode, system mitigations). You follow all the [best practices](#best-practices) outlined below.

Core Knowledge

• **Vercel ships a multi-layered firewall**, not just a CDN. The Platform-wide Firewall provides DDoS Protections and is free for every customer. Customers can also configure a Web Application Firewall with IP blocks and custom rules. Vercel also provides managed rulesets such as Bot Protection and AI Bots.
• **Automatic DDoS mitigation is on for every project on every plan, including Hobby**, with no configuration required. It covers L3/L4/L7 attacks.
• **Vercel does not bill for traffic blocked by DDoS mitigations or WAF.** Usage is only incurred for requests served before mitigation kicked in or not classified as an attack. You do not pay for requests or bandwidth for denies, challenges, or rate-limits from WAF custom rules or managed rules.
• **Custom rules** allows the user to define their own Firewall rules. Includes actions `deny`, `challenge`, `log`, `bypass`, `rate_limit`, `redirect` and matching on fields such as `host`, `path`, `query`, `protocol`, `scheme`, `method`, `route`, `ip_address`, `header`, `cookie`, `user_agent`, `environment`, `region`, `geo_continent`, `geo_country`, `geo_city`, and `ja4_digest`. See https://vercel.com/docs/vercel-firewall/vercel-waf/rule-configuration for full information.

Overview

Project must be linked first (`vercel link`).

vercel firewall overview                  # active rules, blocks, bypasses, attack-mode, drafts
vercel firewall overview --json
vercel firewall diff                      # show unpublished draft changes
vercel firewall diff --json

`rules` and `ip-blocks` changes are **staged** as drafts — run `vercel firewall publish --yes` to make them live. `system-bypass`, `attack-mode`, and `system-mitigations` take effect **immediately**.

Custom rules

[Custom rules](https://vercel.com/docs/vercel-firewall/vercel-waf/custom-rules) define traffic policies based on request attributes. Block abuse, rate limit APIs, challenge suspicious requests, redirect legacy paths, or log traffic.

View

vercel firewall rules list                          # table of all rules
vercel firewall rules list --expand                 # show conditions + actions
vercel firewall rules list --json
vercel firewall rules inspect "My Rule"             # full detail of one rule
vercel firewall rules inspect "My Rule" --json

Create — four modes

# AI — TTY only, BLOCKED FOR AGENTS/SCRIPTS
vercel firewall rules add --ai "Rate limit /api to 100 requests per minute by IP"

# Interactive wizard — TTY only, BLOCKED FOR AGENTS/SCRIPTS
vercel firewall rules add

# Flags — works in scripts and agents
vercel firewall rules add "Block crawlers" \
  --condition '{"type":"user_agent","op":"sub","value":"crawler"}' \
  --action deny --yes

# JSON — works in scripts and agents
vercel firewall rules add --json '{"name":"Block crawlers","conditionGroup":[{"conditions":[{"type":"user_agent","op":"sub","value":"crawler"}]}],"action":{"mitigate":{"action":"deny"}}}' --yes

Multiple conditions (AND) and OR groups

# AND — multiple --condition flags in the same group
vercel firewall rules add "Secure admin" \
  --condition '{"type":"path","op":"pre","value":"/admin"}' \
  --condition '{"type":"geo_country","op":"eq","neg":true,"value":"US"}' \
  --action deny --yes

# OR — use --or to start a new group
vercel firewall rules add "Block dangerous methods" \
  --condition '{"type":"method","op":"eq","value":"DELETE"}' \
  --or \
  --condition '{"type":"method","op":"eq","value":"PATCH"}' \
  --action challenge --yes

Edit and manage

vercel firewall rules edit "My Rule" --action challenge --yes      # change action
vercel firewall rules edit "My Rule" --name "New Name" --yes       # rename
vercel firewall rules edit "My Rule" --enabled --yes               # enable
vercel firewall rules edit "My Rule" --disabled --yes              # disable
vercel firewall rules edit "My Rule" \
  --condition '{"type":"path","op":"pre","value":"/new"}' --yes    # replace conditions

vercel firewall rules enable  "My Rule"
vercel firewall rules disable "My Rule"
vercel firewall rules remove  "My Rule" --yes