Best Free Monitoring Tools in 2026
Monitoring free tiers are unusually generous, and the reason is worth knowing: this is a land-grab category. Vendors would rather have your telemetry flowing at zero than watch you build something yourself, because once your dashboards and alerts live in their product, leaving costs a quarter of engineering time.
So the free allowances are real. New Relic includes 100GB of ingest a month. Grafana Cloud includes 50GB of logs, 50GB of traces and 10,000 metric series. Both are enough to monitor a small production estate properly rather than nominally.
Here is what each gives you, checked August 2026.
Quick comparison
| Tool | Free tier | Paid entry | Rating | Reviews |
|---|---|---|---|---|
| Prometheus | Free, open source | Your servers | not rated | - |
| Grafana Cloud | 10k series, 50GB logs, 50GB traces, 14-day retention | Usage-based | 4.5 | 243 |
| New Relic | 100GB ingest/mo, one full user | Usage plus per-user | 4.4 | 780 |
| Sentry | 1 user, 5,000 errors/mo | $26/mo (Team) | 4.6 | 296 |
| Datadog | Trial only | $15/host/mo (Infrastructure, annual) | 4.5 | 1,092 |
Ratings aggregated by Toolradar across G2 and Capterra.
Note the last row. Datadog is the market leader in this category and it is the only one here without a free tier at all.
The ratings are unusually close, and that is informative
Datadog 4.5 across 1,092 reviews. Sentry 4.6 across 296. Grafana 4.5 across 243. New Relic 4.4 across 780. Four tools within two tenths of each other, on samples large enough to mean something.
That tightness is worth reading. In most categories we cover, the scores spread by half a point or more and the spread tells you something: an incumbent people resent, a challenger people love, a consumer population that disagrees with a business one. Here they do not spread, which says these are all mature products that do what they claim.
The consequence is that ratings cannot decide this for you. Every tool in this comparison works. What differs is the pricing model, and that is where the real risk sits: Datadog's per-host billing is the most predictable per unit and the hardest to forecast in total, while the free tiers differ by two orders of magnitude in what they include.
Notably, Datadog's 4.5 is a good score for a product whose bills are a recurring topic of engineering conversation. People rate whether the software works, not whether the invoice was pleasant, which is a general limitation of ratings and a specific one here.
Prometheus has no aggregated rating, being an open-source project installed rather than purchased, which is the pattern across every developer category in this series.
Grafana Cloud: the most generous free tier
Aggregated rating 4.5 across 243 reviews. Grafana Cloud's free tier covers 10,000 metric series, 50GB of logs, 50GB of traces and 14-day retention, with usage-based pricing above.
That is a complete observability stack at no cost, and for a small production system it is genuinely enough. Metrics, logs and traces in one place, queryable together, which is the thing that turns an incident from guesswork into a sequence.
It is also the managed version of tooling many teams already self-host, so the concepts and the query languages transfer. If you know Prometheus and Loki, you know this.
The 14-day retention is the free tier's real limit. It is shorter than most incident review cycles, so a question raised in a monthly retrospective may reach past your data.
New Relic: 100GB a month, and one full user
Aggregated rating 4.4 across 780 reviews (4.4 on G2, 4.5 on Capterra). New Relic's free tier includes 100GB of ingest per month and one full-platform user, with usage-based pricing and per-user charges above that.
100GB is a lot for a small estate, and unlike Grafana's split allowances it is one number covering everything you send. Simpler to reason about, and harder to predict which signal is consuming it.
The one-user limit is the catch, and it is the same shape as Sentry's: monitoring is a team activity, and the second person who needs to look at a dashboard at three in the morning is the person who triggers the upgrade.
What you get is genuinely broad: APM, infrastructure, logs, browser and mobile monitoring in one platform.
Prometheus: free software, and the standard everything speaks
Prometheus is free and open source under Apache 2.0. The cost is the servers you run it on and the engineering to keep it healthy.
Prometheus is the de facto standard for metrics, and its exposition format is what most software emits natively now. That matters beyond Prometheus itself: choosing it means your instrumentation is portable, because every hosted vendor here can ingest it.
Running it is real work: storage, retention, high availability, and Alertmanager as a separate concern. Paired with Grafana for dashboards it is the classic self-hosted stack, and it is genuinely cheaper at large scale.
At small scale it is more expensive than free hosted tiers once you count your own time, which is the calculation most teams skip.
Sentry: errors first, monitoring second
Aggregated rating 4.6 across 296 reviews, the highest here. Sentry's free Developer plan covers one user and 5,000 errors a month, with Team at $26 a month billed annually.
Sentry answers a different question from the others. Metrics tell you the service is degraded; Sentry tells you which exception, in which line, for which user. During an incident that is often the faster path to the cause.
Most teams end up running Sentry alongside a metrics tool rather than instead of one, and the free tiers of both make that combination cost nothing to start.
Datadog: no free tier, and the reason people still buy it
Aggregated rating 4.5 across 1,092 reviews (4.4 on G2, 4.6 on Capterra), the largest sample here. Datadog offers a trial rather than a free tier, with Infrastructure from $15 per host per month on annual billing and APM priced separately.
It is here because it is the benchmark: the widest integration coverage in the category, and correlation between metrics, traces and logs that genuinely works rather than technically exists.
The cost model is per host and per product, which is predictable per unit and hard to forecast in total, and Datadog bills are a recurring topic of engineering conversation for a reason.
If you are choosing on free, it is not in the running. If you are choosing on capability at scale, it usually wins.
What free monitoring costs
Retention is the hidden limit, not volume. Grafana Cloud's free tier keeps 14 days. If your incident review happens monthly, the data behind the question is already gone. Check retention before allowance, because a large allowance with a short window answers fewer questions than the reverse.
Cardinality is what actually blows the budget. A metric labelled with something high-cardinality, a user ID, a request ID, a full URL, multiplies into thousands of series from one line of code. This is the single most common way teams exhaust a metrics allowance, and it always looks like an innocent label at the time.
Free tiers cap users, not just data. New Relic and Sentry both allow one full user free. Monitoring nobody can see during an incident is not monitoring, so treat the seat limit as the real ceiling.
How to choose
For a small production system, Grafana Cloud, whose free tier is the most complete stack available at zero, with an eye on the 14-day retention.
If you want one number to reason about, New Relic's 100GB a month, remembering the single-user limit.
If you have the operational capacity and the scale, Prometheus with Grafana, self-hosted, which is genuinely cheaper past a certain size.
For finding the cause rather than noticing the symptom, Sentry alongside whichever metrics tool you choose.
Datadog when integration breadth outweighs cost, and price it per host before committing.
Start with instrumentation that is portable, which in practice means emitting Prometheus-format metrics and OpenTelemetry traces. Every option here ingests both, so the expensive decision, how your code is instrumented, stays reversible.
Related: our guide to free error tracking tools covers the exception side, and the Dupple reviews directory has current pricing.
FAQ
Which monitoring tool has the best free tier?
Grafana Cloud, which gives a complete stack: 10,000 metric series, 50GB of logs, 50GB of traces and 14-day retention. New Relic's 100GB of monthly ingest is simpler to reason about but limits you to one full-platform user.
Does Datadog have a free tier?
No, only a trial. Infrastructure monitoring starts at $15 per host per month on annual billing, with APM priced separately. It is the leader on capability and the only tool in this comparison you cannot run at zero cost.
Is self-hosting Prometheus cheaper?
At scale, yes, and meaningfully so. At small scale it is more expensive than a free hosted tier once you count the engineering time to run, store and keep it available. The stronger argument for Prometheus is portability: its format is what everything speaks, so your instrumentation is not locked to a vendor.
What blows a free monitoring allowance fastest?
High-cardinality labels. Attaching a user ID, request ID or full URL to a metric turns one series into thousands, and it is the most common cause of a team exhausting a metrics quota. Check your labels before you check your plan.
Which monitoring tool is rated highest?
Sentry at 4.6 across 296 aggregated reviews, though the field is unusually tight: Datadog and Grafana both sit at 4.5 and New Relic at 4.4. When four mature products score within two tenths of each other, the ratings are telling you they all work, and the decision has to be made on pricing model and free tier instead.
Do Datadog's ratings reflect its cost?
Not really, and that is a limitation worth knowing. Its 4.5 across 1,092 reviews measures whether the software does its job, which it does very well. Bill predictability is a separate concern that star ratings capture poorly, and it is the most common complaint about Datadog in practice.
