Simple pricing

Start free. Upgrade when you need more projects and longer history. No overages, no surprise log bills.

$0 forever

Good for small apps, background jobs, and anyone who wants a simple dashboard for important events.

  • 3 projects
  • 200 events / day
  • 600 retained events total
  • 72-hour retention
  • Dashboard + MCP access
Start free — no card needed
Feature Free Paid
Projects 3 25 per paid unit
Events per day 200 2,000
Retained events total 600 50,000
Event retention 72 hours 14 days
Payload size limit 256 KB 1 MB
Burst limit 60 / min 300 / min
Stackable plan units
Dashboard project overview
MCP topic summaries
Extended detail views
Price Free $9 / mo
What happens when I hit the daily event limit?
Events over the limit are dropped with a 429 response. Your existing events are never deleted — just no new ones are accepted until the next UTC day. There are no overage charges.
What does "stackable paid" mean?
Each paid unit adds capacity for 25 projects. If someone needs more than that, the plan can stack instead of forcing them into a completely different product tier.
What payload access do I get on paid?
Paid projects are intended to keep more event history and richer detail available for review. The repo is currently moving toward safer project-scoped and AI-friendly payload access, so the exact raw-detail UX is evolving with that work.
What is an "MCP token" vs an "ingest token"?
An ingest token (slf_pub_…) goes in your Worker or Lambda — it authorizes POSTing events. An MCP token (slf_mcp_…) is for AI tools that read your project data. Over time, sulfur is moving toward more modern remote MCP authorization flows, but the distinction between write tokens and AI read access stays important.
Can I cancel at any time?
Plan capabilities are defined in the product today, but automated billing is not fully self-serve yet. Contact [email protected] for current paid-plan handling or account changes.
Do I need a credit card to start?
No. The free plan requires only an email address. A card is only needed when you upgrade to paid.
What AI clients work with sulfur?
Any client that supports the Model Context Protocol (MCP) over HTTP. That includes Claude Desktop, Cursor, and any tool built on the MCP standard. Configure it once with your MCP token and start asking questions in plain English.