Sentry Rate Limits & Quota Optimization Skill

Sentry Rate Limits & Quota Optimization

Overview

Manage Sentry rate limits, sampling strategies, and quota usage to control costs without losing visibility into critical errors. Covers client-side sampling, beforeSend filtering, server-side inbound filters, per-key rate limits, spike protection, and the usage stats API.

Prerequisites

Sentry account with a project DSN configured
SENTRY_AUTH_TOKEN with org:read and project:write scopes (Settings > Auth Tokens)
SENTRY_ORG and SENTRY_PROJECT slugs known
SDK installed: @sentry/node (npm) or sentry-sdk (pip)
Current event volume visible at sentry.io/stats/

Instructions

Step 1 — Understand Rate Limit Behavior

When your project exceeds its quota, Sentry returns 429 Too Many Requests with a Retry-After header. The SDK automatically stops sending events until the cooldown expires. Events generated during this window are permanently lost — there is no replay mechanism.

Rate limit tiers by plan:

| Plan | API Rate Limit | Notes | |------|---------------|-------| | Developer | 50 RPM | Shared quota, no reserved volume | | Team | 1,000 RPM | Per-organization, includes spike protection | | Business | 10,000 RPM | Per-organization, custom quotas available | | Enterprise | Custom | Negotiated per contract |

Quota categories (billed separately):

Errors — exceptions and log messages
Transactions — performance monitoring spans
Replays — session replay recordings
Attachments — file uploads (crash dumps, minidumps)
Profiles — continuous profiling data
Cron monitors — scheduled job check-ins

Rate limit headers returned on 429:

HTTP/1.1 429 Too Many Requests
Retry-After: 60
X-Sentry-Rate-Limit-Limit: 50
X-Sentry-Rate-Limit-Remaining: 0
X-Sentry-Rate-Limit-Reset: 1711324800

Step 2 — Configure Client-Side Sampling

Sampling is the first line of defense. Set sampleRate for errors and tracesSampleRate for performance transactions.

TypeScript / Node.js:

import * as Sentry from '@sentry/node';

Sentry.init({
  dsn: process.env.SENTRY_DSN,

  // Error sampling: 0.0 (drop all) to 1.0 (capture all)
  sampleRate: 0.25, // Capture 25% of errors

  // Transaction sampling: 0.0 to 1.0
  tracesSampleRate: 0.1, // Capture 10% of transactions

  // Dynamic transaction sampling — route-aware cost control
  tracesSampler: (samplingContext) => {
    const { name, parentSampled } = samplingContext;

    // Respect parent sampling decision in distributed traces
    if (parentSampled !== undefined) return parentSampled;

    // Drop health checks and readiness probes entirely
    if (name === 'GET /health' || name === 'GET /readiness') return 0;
    if (name?.includes('/health')) return 0;

    // High-value: payment and auth flows at 100%
    if (name?.includes('/api/payment') || name?.includes('/api/auth')) return 1.0;

    // Medium-value: API routes at 20%
    if (name?.startsWith('GET /api/') || name?.startsWith('POST /api/')) return 0.2;

    // Low-value: static assets — never trace
    if (name?.startsWith('GET /static/') || name?.startsWith('GET /assets/')) return 0;

    // Default fallback: 5%
    return 0.05;
  },
});

Python:

import sentry_sdk

def traces_sampler(sampling_context):
    tx_name = sampling_context.get("transaction_context", {}).get("name", "")

    # Drop health checks
    if "/health" in tx_name or "/readiness" in tx_name:
        return 0

    # High-value flows
    if "/api/payment" in tx_name or "/api/auth" in tx_name:
        return 1.0

    # API routes
    if tx_name.startswith(("GET /api/", "POST /api/")):
        return 0.2

    # Static assets
    if tx_name.startswith(("GET /static/", "GET /assets/")):
        return 0

    return 0.05

sentry_sdk.init(
    dsn=os.environ["SENTRY_DSN"],
    sample_rate=0.25,          # 25% of errors
    traces_sample_rate=0.1,    # 10% of transactions (fallback if no sampler)
    traces_sampler=traces_sampler,
)

Step 3 — Filter Noisy Errors with beforeSend

Use beforeSend to drop events before they count against your quota. This runs client-side, so filtered events never reach Sentry.

TypeScript / Node.js:

Sentry.init({
  dsn: process.env.SENTRY_DSN,

  beforeSend(event, hint) {
    const error = hint?.originalException as Error | undefined;

    // Drop browser extension errors (common in frontend SDKs)
    if (event.exception?.values?.some(e =>
      e.stacktrace?.frames?.some(f =>
        f.filename?.includes('extensions://') ||
        f.filename?.includes('moz-extension://') ||
        f.filename?.includes('chrome-extension://')
      )
    )) {
      return null; // Drop the event
    }

    // Drop known noisy browser errors
    if (error?.message?.match(/ResizeObserver loop/)) return null;
    if (error?.message?.match(/Non-Error promise rejection/)) return null;
    if (error?.name === 'AbortError') return null;
    if (error?.message?.match(/Load failed/)) return null;

    // CRITICAL: Always capture payment errors regardless of sampleRate
    if (error?.message?.includes('PaymentError') ||
        event.tags?.['transaction.type'] === 'payment') {
      return event; // Force capture
    }

    return event;
  },

  // Pattern-based error filtering (faster than beforeSend for known strings)
  ignoreErrors: [
    'ResizeObserver loop completed with undelivered notifications',
    'Non-Error promise rejection captured',
    /Loading chunk \d+ failed/,
    'Network request failed',
    'Failed to fetch',
    'AbortError',
    /^Script error\.?$/,
    'TypeError: cancelled',
    'TypeError: NetworkError when attempting to fetch resource',
  ],

  // Block errors originating from third-party scripts
  denyUrls: [
    /extensions\//i,
    /^chrome:\/\//i,
    /^chrome-extension:\/\//i,
    /^moz-extension:\/\//i,
    /hotjar\.com/,
    /google-analytics\.com/,
    /googletagmanager\.com/,
    /intercom\.io/,
  ],
});

Python:

def before_send(event, hint):
    if "exc_info" in hint:
        exc_type, exc_value, _ = hint["exc_info"]

        # Drop known noisy exceptions
        if exc_type.__name__ in ("ConnectionResetError", "BrokenPipeError"):
            return None

        # Drop health check 404s
        msg = str(exc_value)
        if "health" in msg.lower() and "404" in msg:
            return None

    # Always capture payment errors
    if event.get("tags", {}).get("transaction.type") == "payment":
        return event

    return event

sentry_sdk.init(
    dsn=os.environ["SENTRY_DSN"],
    before_send=before_send,
    ignore_errors=[
        "ConnectionResetError",
        "BrokenPipeError",
    ],
)

Step 4 — Enable Server-Side Inbound Data Filters

Inbound filters run on Sentry's servers before quota counting. Filtered events do not consume quota — this is free filtering.

Configure at Project Settings > Inbound Filters:

| Filter | What it blocks | Recommended | |--------|---------------|-------------| | Legacy browsers | IE 9/10, old Safari, old Android | Enable | | Browser extensions | Errors from browser extension code | Enable | | Localhost events | Events from localhost / 127.0.0.1 | Enable for production projects | | Web crawlers | Bot-generated errors (Googlebot, etc.) | Enable | | Filtered releases | Specific release versions | Use for deprecated releases | | Error message patterns | Custom regex patterns | Add known false-positive patterns |

Configure via API:

# Enable legacy browser filter
curl -X PUT \
  -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"active": true}' \
  "https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/filters/legacy-browsers/"

# Enable browser extension filter
curl -X PUT \
  -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"active": true}' \
  "https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/filters/browser-extensions/"

# Enable web crawler filter
curl -X PUT \
  -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"active": true}' \
  "https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/filters/web-crawlers/"

Step 5 — Set Per-Key Rate Limits

Each DSN (Client Key) can have its own rate limit. This prevents a single project from exhausting the organization's entire quota.

Configure at Project Settings > Client Keys > Configure > Rate Limiting.

# Set rate limit to 1000 events per hour on a specific client key
# First, list client keys to find the key ID
curl -s -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  "https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/keys/" \
  | python3 -m json.tool

# Then set the rate limit
curl -X PUT \
  -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"rateLimit": {"window": 3600, "count": 1000}}' \
  "https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/keys/$KEY_ID/"

Strategy for multi-environment setups:

Production DSN: 5,000 events/hour (critical errors matter)
Staging DSN: 500 events/hour (only need representative sample)
Development DSN: 100 events/hour (prevent local debugging floods)

Step 6 — Enable Spike Protection

Spike protection is auto-enabled on Team and Business plans. It detects sudden event volume increases and temporarily rate-limits the project to prevent quota exhaustion from error storms.

Configure at Organization Settings > Spike Protection.

When spike protection triggers:

Sentry detects volume exceeding 10x normal baseline
Events are temporarily dropped (429 returned to SDK)
An email notification is sent to organization owners
Protection auto-disables after the spike subsides

For programmatic spike alerts, set up a Sentry alert rule:

Condition: Number of events in project exceeds threshold
Action: Send notification to Slack/PagerDuty/email
Frequency: Alert once per hour

Step 7 — Monitor Quota Usage via API

# Organization-wide usage stats for the last 7 days, grouped by category
curl -s -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  "https://sentry.io/api/0/organizations/$SENTRY_ORG/stats_v2/?field=sum(quantity)&groupBy=category&interval=1d&statsPeriod=7d" \
  | python3 -m json.tool

# Per-project usage breakdown
curl -s -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  "https://sentry.io/api/0/organizations/$SENTRY_ORG/stats_v2/?field=sum(quantity)&groupBy=project&category=error&interval=1d&statsPeriod=7d" \
  | python3 -m json.tool

# Outcome-based stats (accepted, filtered, rate_limited, invalid)
curl -s -H "Authorization: Bearer $SENTRY_AUTH_TOKEN" \
  "https://sentry.io/api/0/organizations/$SENTRY_ORG/stats_v2/?field=sum(quantity)&groupBy=outcome&category=error&interval=1d&statsPeriod=24h" \
  | python3 -m json.tool

Step 8 — Reduce Payload Size and Deduplicate

Reduce event size and improve grouping to lower quota consumption:

Sentry.init({
  dsn: process.env.SENTRY_DSN,
  maxBreadcrumbs: 30,   // Default: 100
  maxValueLength: 500,   // Default: 250

  beforeSend(event) {
    // Truncate large request bodies
    if (event.request?.data && typeof event.request.data === 'string') {
      event.request.data = event.request.data.substring(0, 1000);
    }
    // Remove cookies
    if (event.request?.cookies) delete event.request.cookies;

    // Custom fingerprinting: normalize dynamic values for better grouping
    if (event.exception?.values?.[0]) {
      const { type, value } = event.exception.values[0];
      const normalized = value
        ?.replace(/\b[0-9a-f]{8}(-[0-9a-f]{4}){3}-[0-9a-f]{12}\b/gi, '<UUID>')
        ?.replace(/\b\d+\b/g, '<N>') || '';
      event.fingerprint = [type || 'unknown', normalized];
    }
    return event;
  },
});

Output

After completing these steps, you will have:

Sampling rates configured (sampleRate, tracesSampleRate, tracesSampler) to reduce event volume while preserving visibility into critical paths
beforeSend filtering dropping noisy browser errors (ResizeObserver, AbortError, extension errors) before they count against quota
ignoreErrors and denyUrls patterns blocking known false positives
Server-side inbound filters enabled for free pre-quota filtering
Per-key rate limits set to prevent single-project quota exhaustion
Spike protection enabled and alert rules configured
Quota monitoring via the /stats_v2/ API endpoint
Custom fingerprinting reducing event duplication

Error Handling

| Error | Cause | Solution | |-------|-------|----------| | 429 Too Many Requests | Quota exhausted for current billing period | Lower sampleRate and tracesSampleRate, add patterns to ignoreErrors, enable per-key rate limits | | Events silently dropped | Client SDK respecting Retry-After header | Reduce volume at source; SDK auto-recovers after cooldown expires | | Critical errors missed | sampleRate too low | Use beforeSend to force-return critical errors regardless of sampling; never filter payment/auth errors | | Quota exhausted early in period | No per-project rate limits | Set hourly rate limits per client key to spread quota evenly across the billing period | | Spike consuming entire quota | Spike protection not enabled or threshold too high | Enable spike protection in organization settings; set up volume alert rules | | 401 Unauthorized on stats API | Invalid or expired auth token | Regenerate token at Settings > Auth Tokens with org:read scope | | Inbound filter not reducing volume | Filter configured but wrong error type | Verify filter targets correct category; browser extension filter only works for JS SDK errors | | tracesSampler not called | tracesSampleRate takes precedence in some SDK versions | Remove tracesSampleRate when using tracesSampler — they conflict |

Examples

Example 1 — Quota Monitoring Bash Script

#!/usr/bin/env bash
# Monitor Sentry quota usage and alert if approaching limit
set -euo pipefail

ORG="${SENTRY_ORG:?Set SENTRY_ORG}"
TOKEN="${SENTRY_AUTH_TOKEN:?Set SENTRY_AUTH_TOKEN}"
THRESHOLD=${QUOTA_THRESHOLD:-80}  # Alert at 80% usage

accepted=$(curl -s -H "Authorization: Bearer $TOKEN" \
  "https://sentry.io/api/0/organizations/$ORG/stats_v2/?field=sum(quantity)&groupBy=outcome&category=error&statsPeriod=1h&interval=1h" \
  | python3 -c "
import json, sys
data = json.load(sys.stdin)
for g in data.get('groups', []):
    if g['by'].get('outcome') == 'accepted':
        print(g['totals']['sum(quantity)']); break
else: print(0)")

echo "Accepted events (last hour): $accepted"
[ "$accepted" -gt "$THRESHOLD" ] && echo "WARNING: volume $accepted > threshold $THRESHOLD"

Example 2 — Enable All Inbound Filters via API

#!/usr/bin/env bash
set -euo pipefail
BASE="https://sentry.io/api/0/projects/$SENTRY_ORG/$SENTRY_PROJECT/filters"
AUTH="Authorization: Bearer $SENTRY_AUTH_TOKEN"

for filter in legacy-browsers browser-extensions web-crawlers; do
  curl -s -X PUT -H "$AUTH" -H "Content-Type: application/json" \
    -d '{"active": true}' "$BASE/$filter/" && echo "Enabled: $filter"
done

Resources

Quota Management — billing categories, quota limits, and overage handling
Manage Your Event Stream — step-by-step cost reduction guide
Sampling Configuration — sampleRate, tracesSampleRate, tracesSampler
Filtering Events — beforeSend, ignoreErrors, denyUrls
Inbound Data Filters — server-side free filtering
Rate Limiting API — per-key rate limit configuration
Stats API v2 — usage monitoring endpoint

Next Steps

Cost review: Query /stats_v2/ weekly to track spend trends by category
Alert rules: Create Sentry alerts for volume spikes per project
Replay sampling: Apply replaysSessionSampleRate and replaysOnErrorSampleRate for session replay cost control
Server-side sampling: Explore Sentry Dynamic Sampling (server-side) for organization-wide policies
Audit ignoreErrors: Review quarterly — patterns may suppress real bugs as code evolves

Agent Skills: Sentry Rate Limits & Quota Optimization

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