Use your serving architecture to frame the choice. Helicone's gateway and Lunary's application observability address related needs, but a migration should treat those layers separately.
Teams comparing a gateway-centered and application-centered workflow
Evaluate Lunary when…
The main problem is understanding customer conversations and the application steps behind a result.
Evaluate Helicone when…
Your team also wants a common model-provider gateway and request operations workflow.
Prove the architecture
Keep routing behavior explicit; do not infer gateway feature parity from an observability comparison.
At a glance
| Area | Lunary | Helicone |
|---|---|---|
| Primary architecture to evaluate | Application telemetry via SDKs or OTEL | AI gateway plus observability |
| Customer context | Chats, threads, user context, feedback | Requests, sessions, and custom properties |
| Prompt workflow | Templates and playground | Prompt management with gateway integration |
| MCP | Read-only developer documentation | Query observability data |
| Migration concern | Instrumentation and historical field mapping | Routing behavior as well as data export |
Map what sits in the request path
A gateway participates in how requests reach providers. Instrumentation records what the application does. Helicone documents a gateway, while Lunary documents SDK and OpenTelemetry ingestion. Before selecting a product, draw the model request path and the telemetry path. Determine whether the team wants to change one or both, and who owns failures in each.
Inspect more than the model response
For a customer-facing assistant, the interesting failure may happen before or after the model call: retrieval selects the wrong document, a tool times out, or the UI shows a fallback response. Trial Lunary with conversation and application context. Trial Helicone with the gateway request and the surrounding custom operations you instrument. Verify that you can reconstruct the same user-visible outcome.
Keep the comparison current
Helicone documents prompts, datasets, exports, and an observability MCP server; it is not limited to basic cost charts. Lunary documents prompts, a playground, conversations, and feedback. Its public Docs MCP server provides documentation rather than project data access. Decide which of these workflows you will actually use, and verify availability in the chosen plan and deployment.
Validate failure behavior before migration
Use a streamed response, a provider error, and a tool timeout in the proof of concept. Check whether retries are distinct operations and whether session and request IDs remain usable. Compare costs over the same completed requests, separating provider charges from platform charges. Preserve the old route until the new system produces a complete explanation of each failure.
Assign an owner to every failure path
If provider access and telemetry share infrastructure, decide how the application behaves when either component is unavailable. If they use separate paths, decide how you detect missing telemetry while serving continues. Exercise those situations in a non-production environment and record the actual result. Neither architecture should win on an assumed reliability advantage: the meaningful evidence is whether requests behave correctly and the responsible team can diagnose the failure.
Common questions
Should I replace my gateway and analytics together?
Only if both changes are necessary and tested. A staged migration makes it easier to identify whether an issue comes from request routing or telemetry.
Can a model tool-call record explain the actual tool execution?
Not by itself. Capture the execution outcome, duration, and error separately, and link it to the model and parent application run.
Sources & methodology
Lunary publishes this guide. We compare documented workflows and explain where each approach fits; this is not an independent benchmark or a hands-on product rating. Features, limits, and commercial terms can change. Check the linked vendor documentation before deciding.