About PromptLedger

Know what every prompt costs. Before the invoice does.

PromptLedger is LLM spend observability for startups: a 5-minute tracking service that shows what each feature and prompt costs, with Slack budget alerts and optional hard caps.

It's built for the team whose OpenAI/Anthropic bill just jumped and who can't answer 'which feature is burning the tokens.' Existing tools are built for ML platform teams; PromptLedger is built for the startup whose bill just hit $8k.

The wedge is cost-first simplicity plus budget enforcement: dollars per feature, hard caps that refuse over-budget log records, flat pricing with no per-seat meter.

What we're not

Not a prompt debugger — we track spend; we don't judge outputs.
No guaranteed savings — costs are estimates and provider invoices are the source of truth.
Not an evals playground — that's Langfuse territory.