kitio.aiLangfuse vs Fiddler AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Langfuse starts at $29/mo and Fiddler AI starts at See pricing page. Check both pricing pages for current plans.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- LLM tracing
- OpenTelemetry support
- Prompt management
- Evaluations and datasets
- Self-hosting
- Agent tracing and observability
- Continuous evaluations
- Real-time guardrails
- ML model monitoring
- AI governance and compliance
- Custom evaluators
| Feature | Langfuse | Fiddler AI |
|---|---|---|
| Best for | Open-source LLM observability, prompt management and evals | Evaluation, observability and guardrails for AI agents and ML models |
| Category | Models & APIs | Models & APIs |
| Pricing model | Freemium | Freemium |
| Starting price | $29/mo | See pricing page |
| Free plan | Yes | Yes |
| Made by | ClickHouse | Fiddler Labs |
| Based in | United States | United States |
| Rating | No ratings yet | No ratings yet |
| Key features |
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Pricing compared
Langfuse starts at $29/mo and Fiddler AI starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
4 plans
Hobby
Free
- Free cloud plan
- Limited usage and history
Core
$29/mo
- 100k units included, $8/100k extra
- 90 days data access
- Unlimited users
Pro
$199/mo
- 3 years data access
- High rate limits
- SOC2 and ISO27001 reports
Enterprise
$2499/mo
- Audit logs and SCIM API
- Uptime and support SLA
- Named support engineer
2 plans
Developer
$0.002 / trace
- Custom evaluators
- Bring your own judge
- RBAC and SSO
- SaaS deployment
Enterprise
Contact sales
- Enterprise guardrails
- SaaS, VPC or on-prem
- Named success manager
Prices in USD, checked Oct 28, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Langfuse
- Free to self-host
- No seat-based fees
- Works with any framework
- Self-hosting needs ops work
- Advanced features on paid tiers
- UI can feel dense
Fiddler AI
- Covers both LLM agents and classic ML
- Pay-per-trace developer pricing
- Self-hosted and VPC options
- Enterprise features need a sales contract
- Free tier limits are not spelled out
- Broad platform with a learning curve
Which one should you choose?
Choose Langfuse if you want:
- Free to self-host
- No seat-based fees
- Works with any framework
Watch out: self-hosting needs ops work.
Choose Fiddler AI if you want:
- Covers both LLM agents and classic ML
- Pay-per-trace developer pricing
- Self-hosted and VPC options
Watch out: enterprise features need a sales contract.
Langfuse vs Fiddler AI FAQ
What is the difference between Langfuse and Fiddler AI?
Langfuse: Open-source LLM observability, prompt management and evals. Fiddler AI: Evaluation, observability and guardrails for AI agents and ML models. Both are models & apis tools.
Is Langfuse or Fiddler AI cheaper?
Langfuse starts at $29/mo and Fiddler AI starts at See pricing page. Check both pricing pages for current plans.
Do Langfuse and Fiddler AI have free plans?
Langfuse: Yes. Fiddler AI: Yes.
Who makes Langfuse?
Langfuse is made by ClickHouse, based in United States.
Who makes Fiddler AI?
Fiddler AI is made by Fiddler Labs, based in United States.
Which should I choose, Langfuse or Fiddler AI?
Choose Langfuse if you value free to self-host and no seat-based fees. Choose Fiddler AI if you value covers both llm agents and classic ml and pay-per-trace developer pricing.