List expression variables
Parse an expression and return the free variables it references, without evaluating it — so an agent can discover which inputs a formula needs before supplying values. A syntax error is a clean 400.
Go to this service →Our latest check (2026-10-11)
- Answering
- Yes — valid x402 payment terms
- Time to answer
- 402 ms
- Price
- $0.004 per call
- Paying buyers, last 30 days
- 2 (directory's own records)
- Paid calls, last 30 days
- 2
- Category
- Unclassified
- Address
- https://math.openverbs.com/v1/variables
Accuracy: paid answers checked against an independent record
Not yet in our paid checks. A seller we have not checked has neither passed nor failed.
For agents
This page as JSON: /sellers/ed22dae0525e.json. Paid lookup by address: GET /api/seller?resource=… ($0.001, x402).