Best Application Monitoring Tools
See inside your applications before users tell you something's broken
Datadog is the modern observability leader with best-in-class UX and broad coverage. New Relic offers strong APM with generous free tier for cost-conscious teams. Sentry is essential for error tracking regardless of other tools. For infrastructure-heavy workloads, consider Prometheus + Grafana as an open-source option.
Modern applications are complex distributed systems. When something goes wrong, you need more than server metrics, you need to trace requests across services, understand application behavior, and catch errors before users complain. The observability market has consolidated around a few major platforms, but costs can spiral quickly. Here's how to get visibility without overspending. Toolradar data: only 298 of the 1,627 developer tools we track are paid only, under 1 in 5, so free application monitoring is widely available.
Top Picks
Based on features, user feedback, and value for money.
| Tool | Starting price | Rating | Best for |
|---|---|---|---|
| Datadog | From $48/mo | 4.5(1,092) | Teams wanting comprehensive, unified observability with the best UX in the market |
| New Relic | From $10/mo | 4.4(784) | Cost-conscious teams wanting strong APM with predictable, usage-based pricing |
| Sentry | Free plan | 4.6(296) | Every development team that wants to catch and fix application errors before users notice |
| Dynatrace | From $7/mo | 4.5(1,456) | Enterprises that need AI-powered observability across cloud, infra, and apps. |
| AppDynamics (Cisco) | From $0.06/mo | n/a | Large enterprises with heavy Java and .NET workloads that need mature APM. |
| Elastic APM | From $95/mo | 4.2(39) | Teams on the Elastic stack that want APM tied to their logging + search. |
| Honeycomb | From $130/mo | 4.8(19) | Engineering teams with complex distributed systems that need high-cardinality observabi... |
| Grafana Cloud (Prometheus + Tempo + Loki) | From $19/mo | 4.5(243) | Engineering teams that want an open-source observability stack with managed hosting. |
Teams wanting comprehensive, unified observability with the best UX in the market
Datadog is the most comprehensive observability platform, infrastructure monitoring, APM, logs, RUM, security, and 750+ integrations in one place.
Watch out
APM requires Infrastructure Monitoring on the SAME hosts: you cannot buy APM alone. APM Pro ($35/host) + Infra Pro ($15/host) = $50/host minimum. Most pricing pages only show the APM price
Cost-conscious teams wanting strong APM with predictable, usage-based pricing
New Relic's freemium model is generous, offering 100 GB/month and a full platform user for free.
Watch out
Data ingest overages at $0.40/GB (Standard)
Every development team that wants to catch and fix application errors before users notice
Sentry is the error tracking standard for development teams, and its pricing is reasonable at low volumes but scales aggressively with event count.
Watch out
Error volume overages: Team and Business include 50K errors. Each additional 50K costs a flat rate that varies by plan. A medium-traffic app generating 500K errors/mo on Team pays significantly more than the $26 base price
Enterprises that need AI-powered observability across cloud, infra, and apps.
Dynatrace's pricing is on the expensive side, particularly for Full-Stack Monitoring at $58/8 GiB host/mo.
Watch out
High cost for additional trace retention
Large enterprises with heavy Java and .NET workloads that need mature APM.
AppDynamics' pricing is on the higher end, especially for the Premium tier at $33/month per core and the SAP Monitoring at $95/month per core, reflecting its enterprise focus.
Watch out
Core-based pricing can escalate quickly.
Teams on the Elastic stack that want APM tied to their logging + search.
Elastic APM's self-managed Free tier is incredibly generous, offering all features at no cost, making it exceptionally fair.
Watch out
Cloud pricing scales with data ingestion/storage
Engineering teams with complex distributed systems that need high-cardinality observability.
Honeycomb's pricing is fair, offering a generous Free tier for small projects.
Watch out
Overage fees if exceeding event limits
Engineering teams that want an open-source observability stack with managed hosting.
Grafana OSS is completely free for self-hosted visualization.
Watch out
Metrics overage at $6.50 per 1,000 active series adds up with high-cardinality data
Other Monitoring worth considering
Beyond the editorial top picks, these are also strong choices we evaluated.
What is Application Monitoring?
Application monitoring (APM) provides visibility into how your applications perform, response times, error rates, throughput, and traces through distributed systems. Modern observability extends this with infrastructure metrics, log aggregation, and real user monitoring. The goal: understand application health and quickly identify issues when things go wrong.
Why Application Monitoring Matters
You can't fix what you can't see. Without monitoring, you discover problems from user complaints, the worst way to learn. Good APM catches issues early, helps you understand performance trends, and significantly reduces time to resolution. For production systems, it's not optional, it's insurance that pays for itself with every incident avoided.
Key Features to Look For
Follow requests across microservices to identify bottlenecks
Capture, aggregate, and alert on application errors with context
Visualize application and infrastructure health
Get notified when things go wrong, with smart noise reduction
Centralize and search application logs
See actual user experience in browsers and apps
Track servers, containers, cloud resources
Anomaly detection and intelligent alerting
Key Factors to Consider
Evaluation Checklist
Pricing Overview
Sentry Developer (free, 5K errors), New Relic Free (100GB/mo), Grafana Cloud Free (10K metrics)
Datadog Infrastructure $15/host + APM $31/host, New Relic Standard $0.35/GB above 100GB
Datadog Enterprise $23/host (infra) + custom APM, Dynatrace ~$69/host, full-stack observability
Mistakes to Avoid
- ×
Sending all logs to Datadog, at $0.10/GB ingestion, a verbose 20-host cluster can generate $500+/month in log costs alone; sample or filter logs aggressively
- ×
Monitoring without alerting, dashboards without alerts are just decoration; set up PagerDuty/OpsGenie integration with escalation policies from day 1
- ×
Paying for full APM when you only need error tracking, Sentry Team at $26/mo covers error tracking for most teams; don't buy Datadog APM ($31/host) just for errors
- ×
Ignoring Prometheus + Grafana, free, open source, and handles infrastructure metrics at any scale; pair with Sentry for errors and you have 80% of Datadog for 90% less
- ×
Not monitoring your monitoring costs, set budget alerts in Datadog/New Relic; a misconfigured agent or log pipeline can generate thousands in unexpected charges
Expert Tips
- →
Start with Sentry (free) + New Relic (free 100GB), this covers error tracking and APM for $0/month; add Datadog only when you need 750+ integrations or superior UX
- →
Sample traces in production, capturing 100% of traces is wasteful; 10-20% sampling catches anomalies while reducing costs by 80-90%
- →
Set meaningful alerts with runbooks, every alert should include: what's broken, who's responsible, and how to fix it; alerts without context create panic, not resolution
- →
Consider the Prometheus + Grafana + Sentry stack, Prometheus for metrics (free), Grafana for dashboards (free), Sentry for errors ($26/mo); total cost ~$26/mo vs. $500+/mo for Datadog
- →
Monitor your monitoring bill, set a monthly budget alert at 80% of target; log volume spikes from a chatty service or bad deploy are the #1 cause of surprise charges
Red Flags to Watch For
- !Per-host + per-GB pricing that scales unpredictably, Datadog Infrastructure ($15/host) + APM ($31/host) + Logs ($0.10/GB) can exceed $200/host/month at scale
- !No free tier or limited trial period, New Relic's 100GB/mo free forever sets the benchmark; tools without a free tier are harder to evaluate
- !Alerting limited to basic thresholds, you need anomaly detection, composite conditions, and intelligent noise reduction to avoid alert fatigue
- !Vendor lock-in on proprietary query languages, tools that use standard PromQL, SQL, or OpenTelemetry are easier to migrate from
The Bottom Line
Sentry (free to $26/mo) is essential for error tracking, install it regardless of other tools. New Relic (free 100GB/mo) offers the best entry point for full APM with predictable pricing. Datadog ($15-31/host/mo) has the best UX and integration coverage but costs escalate fast. For budget-conscious teams, Prometheus + Grafana + Sentry provides 80% of Datadog's value for 90% less.
Frequently Asked Questions
Do I need both APM and error tracking?
APM includes basic error tracking, but dedicated error trackers like Sentry provide much better error management, grouping, assignment, release tracking. Many teams use both: APM for performance visibility, Sentry for error workflows.
How much does application monitoring really cost?
It varies wildly, from free tiers to hundreds of thousands per year at scale. Key cost drivers: number of hosts, data volume (especially logs), retention period, and features enabled. Start small and understand your usage patterns.
Should I use open-source monitoring tools?
Prometheus + Grafana is excellent for metrics and dashboards, especially at scale. But operational overhead is real, you're running the monitoring infrastructure. Managed services cost more but let you focus on your product.
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