LangSmith vs Langfuse vs Helicone 2026 Compared

The pricing question for LLM observability comes down to one word: seats. LangSmith bills per developer, so its $39 entry doubles the moment a second person needs access; Langfuse charges a flat $29 with no per-seat line; Helicone goes flat too at $79. For a small team adding prompt tracing, agent debugging, and token-spend monitoring, that one structural difference moves the total more than any feature does. This article puts the verified prices side by side, works the per-seat math, and flags the recent Helicone ownership change.

1. Headline prices and free tiers

Prices verified against each vendor's pricing page as of May 26, 2026.

Tool	Free tier	Entry paid	Pricing model
LangSmith	Developer: 5K traces/mo[1]	Plus $39/seat/mo (10K traces)[1]	Per seat + trace overage
Langfuse	Hobby: 50K units/mo, 2 users[2]	Core $29/mo (100K units)[2]	Flat, no per-seat
Helicone	Free: 10K requests/mo, 1 user[3]	Pro $79/mo (unlimited seats)[3]	Flat, unlimited seats

All three offer a real free tier for evaluation. On paid entry, Langfuse Core at $29 is the lowest and crucially has no per-seat charge; LangSmith Plus is $39 but per seat; Helicone Pro is $79 with unlimited seats^[1][2][3]. The per-seat distinction is what flips the ranking as teams grow.

2. Per-seat vs per-usage

The meters are the real difference:

• LangSmith charges $39 per seat per month on Plus, with 10,000 traces included and overage at $2.50 per 1,000^[1]. A five-person team pays roughly 5 × $39 before overage.
• Langfuse charges a flat $29 per month on Core for 100,000 units with no per-seat multiplication, so a ten-person team pays the same as a two-person team for equivalent usage^[2].
• Helicone charges a flat $79 per month on Pro with unlimited seats^[3].

For a growing team, the per-seat model is the trap. LangSmith's $39 looks competitive for one developer but multiplies fast at five or ten seats, while Langfuse's flat $29 and Helicone's flat $79 do not. The crossover: Langfuse is cheapest until your trace volume pushes you past its included units, at which point compare the overage rates. Watch token spend alongside traces with the token cost optimization playbook.

3. The Helicone acquisition

Helicone was acquired by Mintlify in early 2026, and the team stated Helicone will continue in maintenance mode: security updates, bug fixes, and new model support keep shipping, but the long-term roadmap is uncertain^[4]. For a production observability dependency, that is a real factor to weigh.

Maintenance mode does not mean broken; Helicone's proxy-based on-ramp remains one of the fastest ways to start logging LLM calls. But if you need a tool with an active, independent feature roadmap, the acquisition tilts the decision toward LangSmith or Langfuse, both of which are actively developed. If Helicone's current feature set covers your needs and you value the quick proxy setup, the maintenance-mode status may be acceptable. Decide based on whether you need new features or just stable logging.

4. Self-host and open source

Langfuse is the open-source, vendor-neutral option of the three, offering both managed cloud and a self-host path^[2]. For a cost-sensitive team or one with data-residency requirements, self-hosting Langfuse can take the recurring SaaS fee to near zero (you pay only for your own infrastructure), at the cost of running and maintaining it yourself.

LangSmith is tied to the LangChain ecosystem and is the natural choice if you already build on LangChain, where its tracing integrates with minimal setup^[1]. Helicone's proxy approach is the lightest-touch integration but now carries the maintenance-mode caveat. So the open-source decision usually comes down to Langfuse: managed for simplicity, self-hosted for cost control and data control.

5. Decision guidance

• Small team, cost-efficient, no per-seat charge: Langfuse Core at $29/mo flat.
• Building on LangChain: LangSmith Plus at $39/seat for tight integration.
• Want self-host or data control: Langfuse (open source, managed or self-hosted).
• Fastest proxy on-ramp, roadmap uncertainty acceptable: Helicone Pro at $79/mo, unlimited seats.
• Need an active independent roadmap: LangSmith or Langfuse over maintenance-mode Helicone.

Re-verify each pricing page before committing; observability pricing and included trace/unit limits change, and the Helicone roadmap is in flux post-acquisition. To fold observability into your wider tooling spend, use the AI stack cost calculator.

All pricing figures verified against official pricing pages as of 2026-05-26.

Frequently asked questions

Which LLM observability tool is cheapest in 2026?

On the entry paid plan, Langfuse Core is cheapest at $29 per month with 100,000 units included and no per-seat multiplication, verified May 2026. LangSmith Plus is $39 per seat per month (10,000 traces included, then $2.50 per 1,000), so a team of five pays five times the base. Helicone Pro is $79 per month with unlimited seats. For a small team, Langfuse's flat $29 with no per-seat charge usually wins; for a solo developer, LangSmith's $39 single seat is competitive. The cheapest depends on team size and trace volume, since the meters differ across the three.

Is Helicone still maintained after the Mintlify acquisition?

Yes, but in maintenance mode. Mintlify acquired Helicone in early 2026, and Helicone's team stated it will keep shipping security updates, bug fixes, and new model support, while the long-term roadmap is uncertain. For a production dependency that is a meaningful concern: maintenance mode means the product keeps working but may not see major new features, and the strategic direction now sits inside Mintlify. If you need a tool with an active, independent roadmap, weigh that against Helicone's strengths. If its current feature set covers your needs and you value its proxy-based on-ramp, it remains usable.

What is the difference between LangSmith, Langfuse, and Helicone?

They overlap as LLM observability but differ in approach and pricing. LangSmith is LangChain's integrated tracing surface, priced per seat ($39) and natural if you already build on LangChain. Langfuse is the open-source, vendor-neutral option with a flat $29 plan, no per-seat charge, and a self-host path. Helicone is the proxy-based fast on-ramp at $79 per month with unlimited seats, now owned by Mintlify and in maintenance mode. Choose LangSmith for LangChain integration, Langfuse for cost-efficient team use and self-hosting, and Helicone for the quickest proxy setup if its roadmap uncertainty is acceptable.