Alye vs Langfuse: LLM observability compared

At a glance

	Alye	Langfuse
How data is collected	Python, Node.js and Java SDKs that wrap the official clients, or OpenTelemetry	SDKs and OpenTelemetry
Open source and self-hosting	SDKs are Apache 2.0; the service is hosted only	Open-source core that can be self-hosted
Free plan	500,000 calls a month, 14 days of history, 3 members	Hobby: 50,000 units a month, 30 days of data access, 2 users
Entry paid plan	Team: $49 a month for 10 million calls, 90 days, unlimited members	Core: $29 a month for 100,000 units, then $8 per 100,000; 90 days; unlimited users
What is counted	One model call; agent steps and tool calls are not counted	Units: traces, observations and scores each count
Regional and marketplace prices	Azure OpenAI deployment types, Vertex AI regions, Bedrock regions and profiles	Not listed on its pricing page
Spend per customer	Built in, with monthly budgets per customer	Views per user and session
Alerts	Spend, forecast, error rate, latency and silent services, to Slack, Teams or email, checked every minute	Spend alerts by email; 2 to 100 alerts depending on plan
Evaluation and prompt management	Not offered	Yes: evaluations, datasets and prompt management

Which one to choose

Choose Langfuse if

You need to self-host for compliance or cost.
Evaluations, datasets and prompt management are your main need.
Your volume is small, so per-unit pricing stays low.

Choose Alye if

You need correct costs for Azure OpenAI, Vertex AI or Bedrock regions.
You bill or budget per customer.
You want alerts in Slack or Teams, not just dashboards and email.
Agents make many steps per request, so per-unit pricing would add up.

Using both

Many teams run both: Langfuse for evaluation and prompt work, Alye for production cost and alerts. Alye adds no proxy, so trying it on one service is low risk.

Also compared: Alye vs Helicone · Alye vs LangSmith. New to the topic? Start with what LLM observability is.

Questions

Is Alye a Langfuse alternative?

For production cost and alerts, yes. Alye records every LLM call and shows cost by service, model and customer, with regional prices and alerts in Slack, Teams or email. It does not do evaluations or prompt management, which are Langfuse strengths.

Which is cheaper, Alye or Langfuse?

It depends on what you send. Langfuse Core is $29 a month for 100,000 units, where traces, observations and scores each count. Alye Team is $49 a month for 10 million model calls, and agent steps and tool calls are not counted. Agents that make many steps per request usually cost less on Alye.

Can I use Alye and Langfuse together?

Yes. Alye adds no proxy, so you can keep Langfuse for evaluation and prompt work and add Alye to the same services for cost per customer and alerts.