Datadog LLM Observability vs Helicone
Both are observability & tracing tools. Here is how they actually differ on price, billing model and deployment.
Datadog LLM Observability
LLM tracing bolted onto the Datadog APM platform. Bills per LLM span rather than per trace, which is the single most misunderstood thing about it - agentic workloads can burn the 40,000-span free tier in a day.
Helicone
An open-source, proxy-based LLM gateway and observability tool - now in maintenance mode after Mintlify acquired it in March 2026. Security and bug fixes only, no roadmap. Not a safe pick for new buyers.
| Datadog LLM Observability | Helicone | |
|---|---|---|
| Category | Observability & Tracing | Observability & Tracing |
| Our rating | 3/5 | 2/5 |
| Starting price | $160/mo | $79/mo |
| Billing meter | span | request |
| Free plan | Yes | Yes |
| Free self-hosting | No or paid tier only | No or paid tier only |
| Best for | Teams already standardised on Datadog for infrastructure and APM, running LLM features inside a larger system, who value one pane of glass over best-in-class eval tooling and can model their span volume accurately. | Almost nobody new - existing users who need a light open-source logging proxy and understand it's frozen. New buyers should look elsewhere. |
Our verdict on Datadog LLM Observability
Datadog LLM Observability is the obvious pick if Datadog is already your monitoring platform, and a poor one otherwise. The correlation story is real - being able to trace an LLM latency spike down through the service, host and database in one product is something no AI-native competitor matches. The eval tooling is competent but not the reason you would buy it. The thing that decides this product is billing. Datadog charges per LLM span, not per trace, and that distinction is where teams get hurt. A simple completion is 3 to 5 spans, but an agentic workflow with tool calls, retrieval and reasoning chains is commonly 20 to 50. Estimate your bill from requests and you will be wrong by more than an order of magnitude. Model span volume first, then decide.
Full Datadog LLM Observability review →Our verdict on Helicone
Helicone was a clean, open-source, proxy-based observability tool - but Mintlify acquired it in March 2026 and put it in maintenance mode. Security patches, bug fixes and new-model support still ship, but there's no roadmap and Mintlify is actively helping customers migrate off. That makes it a dead end for new adopters, no matter how tidy the product is. We rate it low purely on that basis. If you're already on it, plan your exit. If you're evaluating it fresh, don't.
Full Helicone review →Frequently Asked Questions
What is the main difference between Datadog LLM Observability and Helicone?
Datadog LLM Observability: Teams already standardised on Datadog for infrastructure and APM, running LLM features inside a larger system, who value one pane of glass over best-in-class eval tooling and can model their span volume accurately. Helicone: Almost nobody new - existing users who need a light open-source logging proxy and understand it's frozen. New buyers should look elsewhere. Both sit in Observability & Tracing, so the decision usually comes down to billing model and deployment rather than raw capability.
Which is cheaper, Datadog LLM Observability or Helicone?
It depends entirely on your workload shape, because they meter differently - Datadog LLM Observability bills on span and Helicone bills on request. Published starting prices are $160/mo and $79/mo respectively, but those numbers are not comparable until you apply them to the same traffic. Use our cost calculator to model both against your own request volume and span count.
Can I self-host Datadog LLM Observability or Helicone?
Datadog LLM Observability: No or paid tier only. Helicone: No or paid tier only. Free self-hosting means no licence fee, not no cost - you still own the infrastructure, upgrades and on-call.