Langfuse vs Formspree
Open-source LLM engineering platform — observability, prompts, evals
vs. Form backend as a service — point your HTML form at a URL and done
Pricing tiers
Langfuse
Hobby (Cloud Free)
Free. 50k units/month included. 30 days data access. 2 users. Community support.
Free
Self-Hosted (OSS)
MIT-licensed. Docker Compose or Kubernetes deployment. Unlimited.
$0 base (usage-based)
Core
$29/month. 100k units included ($8 per 100k overage). 90 days retention. Unlimited users. In-app support.
$29/mo
Pro
$199/month. 100k units included + same overage. 3 YEARS retention. Unlimited annotation queues. High rate limits.
$199/mo
Teams Add-on
+$300/month. Adds Enterprise SSO + fine-grained RBAC + dedicated Slack support to Pro.
$300/mo
Enterprise
$2,499/month. Everything + custom rate limits, uptime SLA, dedicated support engineer. Yearly options.
$2499/mo
Formspree
Free
$0. 50 submissions/mo. 1 form. Formspree branding in emails. Basic spam filtering.
Free
Basic
$10/mo. 500 submissions/mo. Unlimited forms. Custom success redirect. Honeypot anti-spam.
$10/mo
Professional
$20/mo. 1,000 submissions/mo. reCAPTCHA, webhooks, integrations, rules engine.
$20/mo
Unlimited
$40/mo. 2,500 submissions. File uploads, team members, priority support.
$40/mo
Enterprise
Custom. SSO, SAML, HIPAA, high volume, dedicated support.
Custom
Free-tier quotas head-to-head
Comparing hobby on Langfuse vs free on Formspree.
| Metric | Langfuse | Formspree |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
Langfuse · 16 features
- Annotation Queues — Human reviewers rate traces. Unlimited on Pro+.
- Dashboards — Aggregate metrics, cost, quality across projects.
- Datasets — Curate test sets from production traces. Run experiments.
- EU Cloud Region — GDPR-compliant hosting in EU.
- Evaluations — LLM-as-judge, manual scores, custom model-graded evaluators.
- LLM Cost Tracking — Automatic cost calculation per provider/model.
- OpenTelemetry Native — OTel SDK → Langfuse endpoint works out of box.
- Playground — Test prompts + models + variables live.
- Prompt Management — Version, tag, label prompts. Reference from code by label.
- Public API — Full REST API for ingest, query, prompt management.
- Python @observe decorator — One-line decorator to trace any function.
- Self-Hosting — Docker Compose + k8s Helm chart.
- Sessions — Group related traces (conversations, agent runs).
- Tracing — Capture every LLM call, tool call, nested span with inputs/outputs/cost.
- Users Tracking — Segment traces by user ID, track per-user cost.
- Webhooks — Subscribe to trace completion events.
Formspree · 11 features
- Custom Success Redirect — Redirect after submit.
- Email Notifications — Submissions delivered to inbox.
- File Uploads — Accept attachments (Unlimited).
- IP Filtering — Block spam IPs.
- React SDK — Hooks + state management.
- Rules Engine — Conditional routing, auto-responders.
- Spam Protection — Honeypot + reCAPTCHA + keyword filter.
- Submission Analytics — Volume + source stats.
- Team Members — Multi-user (Unlimited).
- Webhooks — POST submissions to your server.
- Zero Backend — HTML <form action> → email.
Developer interfaces
| Kind | Langfuse | Formspree |
|---|---|---|
| SDK | langfuse-js, langfuse-python | @formspree/core, @formspree/react |
| REST | Langfuse REST API | Formspree REST API |
| MCP | Langfuse MCP Server | — |
| OTHER | Langfuse Dashboard, OpenTelemetry endpoint | Direct HTML Form Submit, Formspree Dashboard, Formspree Webhooks |
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