We moved off our first tracer in month eight. The migration took one engineer the better part of a sprint, because the trace data lived in a schema we did not own. Nobody costed that line item on day one. I am writing this so you can.
I run reliability for a small team shipping LLM features. When the pager goes off at 2am, I do not care which dashboard is prettiest. I care about two numbers: what this tool costs me per month, and what it costs me to leave. Those two numbers are the whole story, and they are almost never on the comparison page.
So here are six Langfuse alternatives. For each I tracked both numbers: the monthly bill on the invoice, and the exit bill that only shows up the day you migrate. I compared Helicone, Arize Phoenix, LangSmith, Braintrust, Laminar, and Future AGI traceAI. They all trace LLM calls (prompts, tokens, retrieval spans, latency). The axis that decides your exit cost is whether the trace format is OpenTelemetry-native or a vendor schema. Get that wrong and the migration bill lands later, with interest.
The cost nobody puts on the pricing page
Your monthly invoice is the visible cost. The exit cost is the invisible one: re-instrumenting the app, rebuilding integrations, and losing historical traces when the schema does not travel. If your spans are OTel, the exit cost trends toward zero because the data is portable by construction. If they are proprietary, you are paying a deferred bill every month you stay. Sort on that first.
