Top API Monitoring Tools in 2025: End-to-End Observability for REST, GraphQL, and WebSockets

APIs are the lifeline of digital businesses in 2025, powering apps and critical services. But a 200 OK isn’t enough; teams must validate payloads, headers, and auth, monitor multi-step workflows, track latency across regions, and cover both public and private endpoints. Modern leaders also support tests-as-code (OpenAPI/Postman) and tie results to SLOs/SLIs to protect user journeys at scale.

CubeAPM is built for this reality. It’s OpenTelemetry-native and unifies API monitoring with logs, metrics, and traces, so a failing assertion or auth step is instantly correlated to the exact service, span, or log line. Teams can validate REST, gRPC, or WebSocket workflows and tie failures directly to traces for instant RCA. With flat pricing of  $0.15/GB, CubeAPM offers predictable costs that legacy vendors can’t match.

In this guide, we’ll compare the Top 10 API Monitoring Tools in 2025, starting with CubeAPM and including Datadog, New Relic, Dynatrace, Postman, Checkly, Grafana Cloud, SmartBear AlertSite, APImetrics, and AWS CloudWatch Synthetics.

Best API Monitoring Tools in 2025

1. CubeAPM – Best for end-to-end API observability
2. Datadog – Best for multi-protocol API coverage
3. New Relic – Best for scripted API monitors and SLA dashboards
4. Dynatrace – Best for AI-driven API anomaly detection and RCA
5. Checkly – Best for developer-first, monitoring-as-code API checks
6. SmartBear AlertSite – Best for API transaction monitoring with SOAP
7. APImetrics – Best for SLA-grade API monitoring with compliance reporting

What is API Monitoring?

API monitoring is the practice of continuously testing APIs to ensure they are not only available but also returning correct and timely responses. It goes beyond a simple 200 OK check to validate payloads, headers, authentication flows, and business logic.

At its core, API monitoring gives teams visibility into how services behave under real conditions. It tracks performance trends, error patterns, and regional differences, helping engineers catch issues like latency spikes, schema mismatches, or authentication failures before they escalate. By combining monitoring with alerting and reporting, organizations can uphold SLAs, reduce downtime, and maintain seamless digital experiences.

Example: How CubeAPM Handles API Monitoring

CubeAPM approaches API monitoring with deep correlation, predictable costs, and an OpenTelemetry-first design. Instead of treating APIs as standalone uptime checks, CubeAPM brings them into the full MELT stack—metrics, events, logs, and traces—so every failure is tied back to its root cause. This means teams can track latency, payload correctness, and error budgets at the endpoint level while still seeing the bigger picture across services and infrastructure.

Here’s how it handles API monitoring:

• Direct OpenTelemetry Compatibility
  CubeAPM fully supports the OpenTelemetry Protocol (OTLP), making it easy to integrate existing OTEL-instrumented services—or even data from other agents—without rewriting instrumentation.
• Flexible Collector Deployment
  You can deploy the OpenTelemetry Collector across environments—from bare-metal servers to Kubernetes clusters or Windows—ensuring consistent collection of metrics, logs, and traces.
• Rich API Insights via Auto-Instrumentation
  Instrumenting frameworks like Node.js Express is straightforward with built-in exporters and auto-instrumentation, allowing trace correlation across API calls with minimal setup.
• Structured Log Ingestion and Trace Linking
  CubeAPM ingests structured and unstructured logs, flattens nested JSON, and ties logs to traces—giving full visibility into API failures and their root causes.
• Custom Alerting with Webhooks
  Alerts can be routed to any webhook endpoint, with payloads fully customizable using templates. This ensures that API-related incidents trigger actionable notifications.
• Cost-Conscious Cloud Monitoring
  For APIs running on AWS services like API Gateway or Lambda, CubeAPM integrates directly via OTEL to avoid expensive log streaming pipelines, reducing monitoring overhead.

Why Teams Choose Different API Monitoring Tools

1. Uptime Alone Doesn’t Cut It

A simple 200 OK check only proves that the endpoint responded, not that it returned the right data. In practice, APIs can silently fail when payloads are malformed, headers are missing, or authentication tokens expire. Without monitoring for correctness, customers may see errors or empty responses even though the service looks “up.”

2. Complex Workflows Need Coverage

Most user experiences rely on chained API calls—login, payment, webhook confirmation, and notification. When one link in that chain fails, the whole workflow breaks. Teams often discover this only after customers complain, since basic checks don’t validate multi-step transactions. API monitoring ensures the entire journey is tested end-to-end.

3. Internal APIs Get Ignored

Public uptime checks don’t cover microservices hidden behind firewalls, VPCs, or service meshes. Yet these internal APIs are just as critical, powering authentication, data processing, and business logic. Without private probes that run inside secure networks, entire classes of failures go undetected.

4. CI/CD Drift Creates Gaps

Testing APIs in staging is common, but those tests rarely get reused once code hits production. Developers complain about “drift” where monitors don’t match real workflows. The result: regressions slip through. Teams want tools that support importing OpenAPI specs, Postman collections, or k6 scripts so tests-as-code can move seamlessly from CI/CD into production monitoring.

5. Costs Spiral Unexpectedly

Legacy vendors charge per test, per location, or per user. That looks fine at low volume, but once teams add more regions or increase frequency, bills balloon. Many Reddit users complain that simple monitoring setups double or triple in cost within months. Flat or ingestion-based pricing models give teams the predictability they need.

6. SLOs and Error Budgets Are Missed

API health isn’t just about uptime—it’s about meeting service-level objectives (SLOs). If latency spikes above 200ms for 5% of calls, error budgets burn faster than expected. Without monitoring tied directly to SLOs, teams don’t realize they’re breaching commitments until SLAs are violated and customers demand credits.

7. Authentication & Security Edge Cases Break

APIs using OAuth2, JWT, or HMAC are common, but monitoring them is tricky. Tokens expire, refresh flows fail, or signatures don’t validate properly. Without tools that handle secure auth workflows, monitoring misses exactly the edge cases most likely to break in production.

8. Lack of Correlation Slows RCA

Knowing an API endpoint is down doesn’t solve the real problem. Teams still need to figure out why it failed—was it the service, the database, the network, or a dependency? Without correlation between API checks, traces, and logs, engineers waste hours triaging blind. Full-stack observability shortens MTTR dramatically.

Top 7 API Monitoring Tools

1. CubeAPM

Known For

An OpenTelemetry-native observability platform that unifies API monitoring with metrics, logs, traces, errors, and infrastructure monitoring. It provides predictable ingestion-based pricing at $0.15/GB, avoiding the hidden charges common with legacy vendors. CubeAPM also offers self-hosted and BYOC deployment models, making it one of the few tools that address strict compliance and data residency requirements. Its Smart Sampling engine reduces noise while retaining critical error and latency traces, delivering both cost efficiency and clarity.

API Monitoring Specific Features

• REST, gRPC, and WebSocket API monitoring
• Multi-step workflows with payload and authentication validation
• Global and private probes for both public and VPC-restricted endpoints
• Correlation of API failures with distributed traces and logs for fast RCA
• Deployment flexibility with SaaS or self-hosted options

Key Features

• Full MELT observability (metrics, logs, traces, RUM, synthetics).
• Extensive integrations ecosystem, 800+ integrations
• OpenTelemetry-native with Smart Sampling for 60–80% cost savings.
• Prebuilt infra/service dashboards with latency and error insights.
• Flexible alerting via Slack, PagerDuty, and webhooks.
• Advanced log pipeline with JSON flattening and indexing.

Pros

• OTEL-first design avoids vendor lock-in
• Transparent per-GB pricing with no per-test charges
• Smart sampling keeps useful traces while reducing noise.
• Strong compliance support (HIPAA, GDPR) through self-hosting
• Unified MELT stack reduces the need for separate vendors

Cons

• Not suited for teams looking for off-prem solutions
• Strictly an observability platform and does not support cloud security management

Pricing

Ingestion-based pricing of $0.15/GB

CubeAPM API Monitoring Pricing At Scale

CubeAPM uses a simple ingestion-based pricing model of $0.15/GB, with API monitoring included at no extra cost. For example, a mid-sized company ingesting 10TB of telemetry per month would pay only $1,500, compared to $7,000–$10,000 with legacy vendors that charge separately for test runs, locations, and data retention. This makes CubeAPM up to 60–80% more cost-effective, while still delivering full MELT observability, OpenTelemetry-native design, and the option to self-host for compliance.

Tech Fit

CubeAPM is a strong fit for SaaS companies, regulated industries, and cloud-native enterprises that need cost transparency, endpoint-level reliability tracking, and SLO-driven monitoring. Its self-hosting option makes it ideal for teams with strict data residency rules, while its per-GB pricing and Smart Sampling make it attractive for organizations handling large-scale telemetry volumes without runaway costs.

2. Datadog

Known For

A market leader in observability with extensive coverage across infrastructure, logs, APM, and security. Datadog is widely recognized for its broad monitoring ecosystem that spans infrastructure, logs, APM, synthetics, and security. Its synthetic monitoring is tightly coupled with dashboards, offering coverage across REST, gRPC, WebSockets, DNS, and more. It is popular among large enterprises that value a unified, feature-rich observability suite despite its higher cost structure.

API Monitoring Specific Features

• REST, gRPC, WebSocket, DNS, SSL, and TCP/UDP checks
• Multi-step workflows with chained requests and assertions
• Global and private locations for both internet-facing and internal APIs
• CI/CD integration to catch regressions before production
• Correlation with Datadog APM, logs, and infrastructure metrics

Key Features

• Universal Service Monitoring with eBPF auto-discovery.
• Continuous Profiler with flame graphs and call graphs.
• Application Security and Exploit Prevention modules.
• Sensitive Data Scanner for logs, spans, and RUM.

Pros

• Broad protocol and scenario coverage
• Mature ecosystem with 900+ integrations
• Strong visualization, dashboards, and alerting options
• Supports private locations for internal/VPC testing

Cons

• Pricing complexity; costs scale quickly with tests, locations, and retention
• High data volume charges make it expensive for mid-to-large workloads
• UI can feel overwhelming for smaller teams just starting out

Pricing

• Infrastructure Monitoring: $23/host/month
• DevSecOps: $34/host/month
• APM: $40/host/month
• Log Ingestion: $0.10/GB ingested or scanned per month
• Standard Log Indexing (15-day retention): $1.70 per million log events per month

Datadog API Monitoring Pricing At Scale

For a mid-sized company ingesting 10TB of telemetry per month and monitoring 50 hosts, Datadog’s bill comes to $1,150/month for infrastructure monitoring, $2,000/month for APM, and $1,000/month for log ingestion. Adding standard log indexing for that volume brings the total to about $9,150/month—over 6x higher than CubeAPM’s flat $1,500/month for the same 10TB workload.

Tech Fit

Datadog fits best with DevOps-heavy, cloud-native organizations that rely on AWS, Azure, or GCP and want deep integrations out of the box. It suits teams that prioritize end-to-end visibility and advanced visualization over pricing predictability. Enterprises running hybrid environments can leverage its global probes and private locations to cover both external and internal APIs. However, organizations at scale must be ready for complex, modular pricing that can escalate quickly.

3. New Relic

Known For

New Relic is best known for its heritage in APM and its ability to combine multiple observability pillars—synthetics, logging, traces, and infrastructure—into a single platform. Its synthetic monitoring supports scripted checks in JavaScript, enabling flexible workflows. The platform also provides detailed SLA dashboards, making it attractive for enterprises with compliance needs. New Relic appeals to teams seeking strong visualization, SLA enforcement, and end-to-end performance insights.

API Monitoring Specific Features

• Scripted API monitors using Node.js (with libraries like got)
• Multi-step transaction monitoring for complex workflows
• Global and private locations to test both public and restricted APIs
• Integration with distributed tracing and error tracking for RCA
• SLA dashboards and compliance-ready reporting

Key Features

• Kubernetes observability with Pixie/eBPF integration.
• AI-powered anomaly detection and forecasting.
• Errors Inbox for grouping and regression tracking.
• Mobile error monitoring with release tracking.

Pros

• Unified platform covering APM, logs, infra, and synthetics
• Private locations support internal or VPC-restricted endpoints
• Mature dashboards and alerting for SLA/SLO tracking
• Easy to script flexible API scenarios with JavaScript

Cons

• Pricing can escalate with test frequency and user seats
• Learning curve for non-developers due to scripting-heavy monitors
• Limited coverage for newer protocols like gRPC compared to rivals

Pricing

• Free Tier: 100GB/month data ingested
• Ingestion-based pricing of $0.35/GB + $400/user/month for full access

New Relic API Monitoring Pricing At Scale

New Relic offers a free tier with 100GB/month, but beyond that, its costs rise quickly. Pricing is $0.35/GB of ingested data, plus $400 per user/month for full platform access. For a mid-sized company ingesting 10TB of telemetry per month and with a team of 5 users, the monthly bill would be $3,500 for ingestion (10,000 GB × $0.35) plus $2,000 for user licenses (5 × $400), totaling $5,500/month. Compared to CubeAPM’s flat $1,500/month for the same 10TB workload, New Relic comes in at nearly 4x higher cost.

Tech Fit

New Relic is best suited for teams that need unified observability with a focus on business SLAs. It works well in organizations where compliance reporting and SLA dashboards are as important as technical monitoring. Engineering teams already invested in New Relic’s ecosystem will benefit most, especially those comfortable with scripted API scenarios. While not the cheapest, it provides value where detailed SLA reporting and observability breadth outweigh cost concerns.

4. Dynatrace

Known For

Dynatrace is known for its AI-driven monitoring platform that leverages its Davis AI engine to deliver automated anomaly detection and RCA. It combines synthetic API monitoring, distributed tracing, real-user monitoring, and infrastructure insights into one system. Its Grail data lakehouse enables index-less log and metric analysis at scale. Dynatrace stands out for large enterprises that prioritize automation, scalability, and intelligent dependency mapping.

API Monitoring Specific Features

• Synthetic API monitoring with multi-step transaction tests
• Global and private locations for both internet-facing and internal APIs
• Protocol support for REST and web-based transactions
• Correlation with distributed traces, logs, and infrastructure metrics
• AI-powered anomaly detection and RCA through the Davis engine

Key Features

• Grail data lakehouse with Davis causal AI.
• AutomationEngine workflows with event-driven actions.
• Session Replay tied to backend traces.
• AI anomaly detection and dependency mapping.

Pros

• Strong automation with Davis AI for pinpointing root causes
• Unified observability across applications, infra, and APIs
• Private locations enable secure internal API testing
• Rich enterprise reporting and SLA tracking features

Cons

• High cost compared to mid-market solutions
• Complexity of setup and learning curve for smaller teams
• Limited flexibility for developer-first “tests-as-code” workflows compared to Postman or Checkly

Pricing

• Full-Stack Monitoring: $0.08 per hour for an 8 GiB host
• Infrastructure Monitoring: $0.04 per hour per host
• Synthetic Monitoring: $0.001 per request
• Logs: $0.20 per GiB

Dynatrace API Monitoring Pricing At Scale

Dynatrace pricing is usage-based across modules. Full-Stack Monitoring is billed at $0.08 per hour for an 8 GiB host ($58/month per host), while Infrastructure Monitoring is $0.04 per hour ($29/month per host). Synthetic Monitoring is charged at $0.001 per request, and logs cost $0.20/GB ingested. For a mid-sized company with 50 hosts and 10TB of logs per month, the bill comes to $2,900 for full-stack monitoring (50 × $58) plus $2,000 for logs (10,000 GB × $0.20). Adding a modest 1M synthetic checks at $0.001 each adds another $1,000, bringing the total to around $5,900/month. Compared to CubeAPM’s flat $1,500/month for the same 10TB workload, Dynatrace costs nearly 4x more.

Tech Fit

Dynatrace is ideal for large global enterprises and regulated industries that demand automation, scalability, and SLA-backed reporting. It works best for organizations managing complex hybrid environments with thousands of services, dependencies, and users across regions. Enterprises prioritizing proactive detection and AI-assisted RCA will gain significant value. Teams must, however, be ready for higher costs and a steeper learning curve compared to leaner tools.

5. Checkly

Known For

Checkly is known as a developer-first monitoring solution with a strong emphasis on monitoring-as-code. It integrates directly with CI/CD pipelines, allowing teams to define checks in JavaScript or TypeScript and reuse OpenAPI or Terraform assets. Its browser monitoring is powered by Playwright, enabling detailed validation of user journeys. Checkly is popular among engineering-driven organizations that prefer lightweight, programmable workflows over enterprise-heavy monitoring stacks.

API Monitoring Specific Features

• REST and GraphQL API monitoring with assertions on status, payload, and headers
• Multi-step workflows for validating chained API calls
• OpenAPI imports and integration with k6 for performance and reliability testing
• 20+ global locations plus private locations for VPC monitoring
• Infrastructure-as-code integrations (Terraform provider, CLI, and API)

Key Features

• Monitoring-as-Code with JS/TS, OpenAPI, Terraform.
• Playwright-based browser checks with video capture.
• Private locations with flexible scheduling.
• Alerting via Slack, Opsgenie, PagerDuty, webhooks.

Pros

• Strong developer experience with JavaScript/TypeScript scripting
• Monitoring-as-code makes it CI/CD friendly
• Easy reuse of existing OpenAPI specs and k6 scripts
• Lightweight and fast compared to larger enterprise tools
• Good balance of global + private probes

Cons

• Smaller ecosystem compared to Datadog or Dynatrace
• Limited enterprise features like advanced SLA reporting
• Requires scripting knowledge for advanced scenarios

Pricing

• Hobby ($0/month): 1 User, 10 Uptime Monitors, Synthetic Monitoring: 1,000 Browser Checks, 10,000 API Checks, Max Frequency: 2 min
• Starter ($24/month): 3 Users, 20 Uptime Monitors, Synthetic Monitoring: 3,000 Browser Checks, 25,000 API Checks
• Team ($64/month) (Most Popular): 10 Users, 50 Uptime Monitors, Synthetic Monitoring: 12,000 Browser Checks, 100,000 API Check

Checkly API Monitoring Pricing At Scale

For a mid-sized team running 10 TB of API checks per month, Checkly’s Team plan—priced at $80/month—includes 100,000 API check runs. That’s a rounded starting cost. Beyond that, overage for additional checks is $2 per 10,000 runs. If your team needs 500,000 total API runs, you’d pay the base $80 plus $80 for overages (400k extra ÷ 10k × $2), totaling $160/month. Compared to CubeAPM’s flat $1,500/month for the same telemetry volume, Checkly is a cost-effective choice—but only until API run volumes grow larger or you add browser tests and private probes.

Tech Fit

Checkly fits best with startups and scale-ups that prioritize developer productivity and automation. It is particularly valuable for teams adopting DevOps or GitOps models who want API and browser monitoring embedded in their pipelines. Organizations that prefer scripting and infrastructure-as-code practices will find it intuitive. While it lacks advanced SLA dashboards, it’s a strong fit for teams that value speed, code reuse, and CI/CD alignment.

6. SmartBear AlertSite

Known For

SmartBear AlertSite is known for its transaction monitoring and SLA compliance features, particularly in QA-driven organizations. It supports both REST and SOAP APIs, making it one of the few modern tools that still cater to legacy systems. Its DejaClick recorder enables codeless browser transaction recording with branching logic.

API Monitoring Specific Features

• REST and SOAP API monitoring with schema and payload validation
• Multi-step transaction monitoring for complex business workflows
• OpenAPI and SoapUI test reuse for consistency between QA and production
• Global monitoring locations plus private nodes for secure environments
• SLA dashboards, compliance-ready reporting, and historical trend analysis

Key Features

• DejaClick browser recorder with branching logic.
• 350+ global nodes plus PrivateNode support.
• SLA dashboards with Apdex and latency metrics.
• Dynamic thresholds and outage analytics.

Pros

• Strong support for SOAP and legacy protocols in addition to REST
• Reuse of SoapUI/OpenAPI tests reduces drift between test and production
• SLA-focused reporting for executive and compliance teams
• Flexible setup for both global and private probes

Cons

• UI and workflows feel dated compared to newer developer-first tools
• Limited integrations with modern observability stacks (OTEL, Grafana, etc.)
• Pricing is less transparent than competitors

Pricing

Pricing is based on a subscription model with tiers depending on the number of monitors, locations, and frequency. While not fully transparent, enterprise deployments typically start around $2K/month and scale upward.

SmartBear AlertSite API Monitoring Pricing At Scale

An enterprise running 4M API checks/month across 10 locations would generally spend $5K/month, depending on SLA reporting and add-ons.

Tech Fit

AlertSite fits best with QA and operations teams in enterprises that need compliance-grade SLA reporting. It is a strong choice for organizations still reliant on SOAP alongside REST APIs. Enterprises seeking detailed SLA dashboards and hybrid deployment models will benefit most. While it may feel dated compared to newer developer-first tools, it remains valuable for regulated or traditional industries where SLA reporting is non-negotiable.

7. APImetrics

Known For

APImetrics is known for its compliance-first API monitoring platform, trusted in industries like banking, telecom, and government. It pioneered CASC scoring, a standardized metric for API reliability and performance. Its dashboards provide SLA/SLO validation with latency heatmaps and global vantage points. APImetrics is often chosen for independent validation in highly regulated, audit-heavy environments.

API Monitoring Specific Features

• REST, SOAP, and GraphQL API monitoring with payload validation
• Multi-step transaction monitoring with chained requests
• 80+ global monitoring locations plus enterprise/private agents
• Advanced SLO/SLA tracking with CASC (Cloud API Service Consistency) scoring
• OAuth2, JWT, and HMAC authentication management for secure APIs

Key Features

• CASC score for standardized API benchmarking.
• AI dashboards with SLO tracking and latency heatmaps.
• Workflow modeling for multi-call processes.
• Auth manager for keys, OAuth, JWT, file uploads.

Pros

• Enterprise-grade SLA and compliance reporting
• Strong authentication support for regulated environments
• Global footprint with 80+ vantage points
• CASC scoring provides a standardized measure of API performance
• Supports both legacy (SOAP) and modern (GraphQL/REST) APIs

Cons

• Less developer-friendly than dev-first tools like Checkly or k6
• Higher learning curve for teams that don’t need compliance-heavy reporting
• Premium pricing compared to mid-market competitors

Pricing

APImetrics uses a subscription model starting around $1K/month, with costs scaling by number of APIs, test frequency, and SLA reporting needs. Enterprise plans for regulated industries can range much higher.

APImetrics API Monitoring Pricing At Scale

A financial services company running 2M API checks/month with 10 global regions would likely spend $8K–$12K/month, depending on compliance reporting and private agent use.

Tech Fit

APImetrics is a strong fit for financial institutions, telecom operators, and government agencies where SLA compliance and external validation are critical. It is designed for organizations that require audit-ready evidence, compliance dashboards, and multi-region performance benchmarks. While less developer-friendly than code-centric tools, it excels in enterprise scenarios where contractual obligations and regulatory audits drive API reliability.

Conclusion

APIs are the backbone of modern applications, but keeping them fast, reliable, and secure is harder than ever. Teams struggle with blind spots in multi-step workflows, rising monitoring costs, and compliance requirements that traditional uptime checks can’t solve.

That’s why choosing the right API monitoring tool matters. From AI-powered platforms like Dynatrace to developer-first options like Checkly and compliance-focused solutions like APImetrics, every tool brings its own strengths. Yet, many fall short on cost transparency and full-stack correlation.

This is where CubeAPM sets itself apart. Built on OpenTelemetry, CubeAPM unifies API monitoring with logs, metrics, and traces—while offering predictable per-GB pricing and self-hosting options for compliance. It gives teams proactive visibility, faster root cause analysis, and up to 60–80% cost savings compared to legacy vendors.