Rate Limiting

Deckyard includes built-in rate limiting to protect against abuse and ensure fair usage.

Overview

Most limits are token buckets. Each bucket has a capacity (the burst size) and a refillPerSec (the sustained rate):

• Burst traffic is allowed up to the bucket capacity
• Tokens refill at a steady rate
• Each request consumes one token; an empty bucket answers 429 Too Many Requests

Depending on the endpoint, a bucket is keyed per client IP, per signed-in user, per email address, per tracking session or per API key (see the tables below). A few older limits (password reset, magic links, guest verification, admin user creation) count requests in a one-hour window instead.

Configuration

Trust Proxy

When running behind a reverse proxy (nginx, Caddy, etc.), enable proxy trust to get the real client IP:

TRUST_PROXY=true

TRUST_PROXY accepts true, 1, yes or on; anything else leaves it off. Without it, every request appears to come from the proxy, so all users share one per-IP bucket (including the login brute-force throttle).

With TRUST_PROXY enabled, Deckyard reads the client IP in this order:

1. X-Forwarded-For: the entry TRUSTED_PROXY_COUNT hops from the right of the chain (default 1, minimum 1). The leftmost entry is supplied by the client and is never trusted.
2. X-Real-IP, if X-Forwarded-For is missing, shorter than the configured hop count, or the selected entry is not a valid IP.
3. The socket’s remote address.

Without TRUST_PROXY, only the socket address is used.

# Number of trusted proxies that append to X-Forwarded-For (default 1)
TRUSTED_PROXY_COUNT=1

Set TRUSTED_PROXY_COUNT to the number of proxies you run in front of Deckyard (for example 2 for a load balancer in front of Caddy).

⚠️ Security: Only enable this when running behind a trusted proxy that sets these headers. Otherwise, clients can spoof their IP address.

Endpoint Limits

Capacity is the burst; the sustained rate is what the bucket refills to after the burst is spent.

Authentication

Endpoint	Keyed by	Limit
Password login	IP	burst 10, then ~6/min
Password login	Email	burst 8, then ~6/min
Password reset requests	Email	3 per hour
Password reset requests	IP	10 per hour
Magic link requests	Email	5 per hour
Magic link requests	IP	15 per hour

A blocked login returns 429. A rate-limited password reset or magic link request still answers 200 with the usual “if your email is registered” message, so the limit cannot be used to probe for accounts; the attempt is logged as an auth event.

Share Links

Endpoint	Keyed by	Limit
Share link password (POST /api/share/:token/verify)	IP	burst 3, then ~3/hour
Guest verification requests	Email	3 per hour

Follow Codes

Endpoint	Keyed by	Limit
Code creation	IP	burst 10, then ~10/hour
Code resolution	IP	burst 60, then ~60/hour

Live Sessions

Endpoint	Keyed by	Limit
Notes companion write (PUT /api/live-sessions/:id/notes/:slideId)	IP	burst 30, then ~1/second

Analytics

Endpoint	Keyed by	Limit
Tracking: session start	IP	burst 10, then 1 per 2 seconds
Tracking: heartbeat	IP	burst 20, then 2/second
Tracking: heartbeat	Session	burst 5, then 1 per 2 seconds
Tracking: session end	IP	burst 10, then 1/second
Tracking: slide view	IP	burst 30, then 3/second
Tracking: slide view	Session	burst 10, then 1/second
Tracking: erase own data	IP	burst 10, then 1 per 5 seconds
Analytics (authenticated)	User	burst 60, then 1/second
Report creation, GDPR export and deletion	User	burst 10, then 1 per 5 seconds
Public report access	IP	burst 10, then 1 per 5 seconds

Admin Operations

Endpoint	Keyed by	Limit
User creation	Admin	20 per hour

Only one bulk export can run per user at a time; a second request returns 429 with error export_in_progress.

Demo and Sandbox Mode

On instances running in demo or sandbox mode, expensive app routes are also limited per IP:

Route group	Limit
Export	burst 8, then ~15/min
Publish	burst 6, then ~12/min
Create presentation	burst 6, then ~12/min
Update presentation	burst 30, then ~60/min
Follow (POST /api/follow/...)	burst 20, then ~60/min

Live Event Streams

The public follow, questions and live-session event streams (Server-Sent Events) are capped by concurrent connections rather than by request rate. These caps are tunable:

SSE_MAX_CONNECTIONS=2000          # total concurrent streams
SSE_MAX_CONNECTIONS_PER_IP=50     # per client IP
SSE_MAX_LIFETIME_MS=21600000      # force-close after 6 hours; clients reconnect

The per-IP cap only applies when the observed client IP is a public address. Behind a proxy without TRUST_PROXY, every stream shares the proxy’s private address, so only the global cap applies. Over the cap, the stream answers 429 with Retry-After: 30.

API Rate Limits

The public API (/api/v1) and MCP tool calls made with an API key share one per-minute bucket per key, sized by the key’s tier:

Tier	Requests per minute	AI calls per day	Exports per day
Free	60	10	50
Pro	300	100	500
Enterprise	1000	unlimited	unlimited

The tiers are rate-limit classes stored on each key, not plans. Every new key gets the free tier, and there is no setting in the app to change it; an admin who needs a higher limit changes the key’s tier column in the api_keys table.

The per-minute limit is a token bucket with the per-minute figure as its burst. The daily AI and export limits reset at midnight UTC.

API responses include rate limit headers:

X-RateLimit-Limit: 86400
X-RateLimit-Remaining: 86155
X-RateLimit-Reset: 1706140800

These headers describe daily usage and reset at midnight UTC (X-RateLimit-Reset is a Unix timestamp). On regular requests, X-RateLimit-Limit is the per-minute rate times 1440, an informational daily ceiling; on export downloads and daily-limit errors it is the daily export or AI limit.

Handling Rate Limits

When rate limited, the API returns HTTP Status: 429 Too Many Requests.

Exceeding the per-minute limit returns Retry-After: 60 and:

{
  "error": "rate_limited",
  "message": "Rate limit exceeded. Please slow down your requests."
}

Exceeding a daily limit returns the X-RateLimit-* headers and:

{
  "error": "rate_limited",
  "message": "Daily export limit exceeded",
  "details": { "limit": 50, "used": 50, "resetAt": "1706140800" }
}

The app’s own endpoints (outside /api/v1) answer 429 with a Retry-After header (in seconds) and a body like { "ok": false, "error": "rate_limited", "message": "Rate limit exceeded" }.

Honor Retry-After where present, and implement exponential backoff in your API clients to handle rate limits gracefully.

IP Address Detection

Deckyard validates IP addresses taken from headers. An X-Forwarded-For chain that is too short for TRUSTED_PROXY_COUNT, or whose selected entry is malformed, is ignored and logged as a warning:

Untrusted/short X-Forwarded-For (len 1, hops 2)

A malformed X-Real-IP is ignored silently.

Supported IP Formats

• IPv4: 192.168.1.1
• IPv6: 2001:0db8:85a3::8a2e:0370:7334
• IPv4-mapped IPv6: ::ffff:192.168.1.1
• Bracketed IPv6: [::1]

Scaling Considerations

When Redis is configured (REDIS_URL or REDIS_HOST, and REDIS_ENABLED not set to false), the token-bucket limits are stored in Redis and shared across all instances. There, each limit is enforced as a sliding window: at most capacity requests per capacity / refillPerSec seconds (for example 10 login attempts per IP per 100 seconds). This allows the same long-run rate as the bucket but no extra burst. If Redis is unreachable, Deckyard falls back to in-memory buckets.

Without Redis, the limiter uses in-memory storage. For multi-instance deployments:

• Each instance maintains its own rate limit buckets
• Effective rate limits are multiplied by the number of instances
• Restarting an instance resets its buckets

Some limits are always per instance, even with Redis: admin user creation and the event stream caps. Password reset, magic link and guest verification limits are counted in the database, so they already hold across instances.

Customizing Limits

There are no environment variables to change or disable the request-rate limits; only the event stream caps above are tunable. The token-bucket values live in one file, server/config/rate-limits.js, which you can edit in your own build:

export const FOLLOW_CODE_LIMITS = {
  create: { capacity: 10, refillPerSec: 10 / 3600 }, // burst 10, ~10/hour
  resolve: { capacity: 60, refillPerSec: 60 / 3600 }, // burst 60, ~60/hour
};

The public API tiers are defined in TIER_LIMITS in server/storage/api-keys.js. The login and share-link password limits are security-relevant; loosening them weakens brute-force protection.

Related

• Authentication
• API Documentation