x402 census · chem.openverbs.com · abc7b3f2f475 · JSON
POST /v1/element
live
Look up a periodic-table element by exactly one of `symbol` (e.g. "Fe"), `name` (e.g. "iron") or atomic `number` (1..118). Returns its number, symbol, name, standard atomic weight and whether that weight is a true standard atomic weight.
Verdict: live. The unpaid GET reached a valid 402 (confirmed by the re-probe of 2026-10-01).
Facts from the catalogs
| Field | Value |
|---|---|
| URL | https://chem.openverbs.com/v1/element |
| Method | POST |
| Price | $0.004 USDC = 4000 atomic units of 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| Network | eip155:8453 (base) |
| payTo | 0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A |
| Seller | chem.openverbs.com |
| Catalogs | cdp (row updated 2026-09-06) |
| Listed since (lower bound) | 2026-09-06 (earliest catalog timestamp; catalogs report last-update times only) |
| Last catalog update | 2026-09-06 |
| CDP quality counters | 3 calls and 1 unique payers in 30 days, last call 2026-09-06 (catalog-reported, not verified on chain) |
| Category (keyword rule) | other/unknown |
| Templated path | no |
| x402Version in catalog | 2 |
| Service name / tags | Element lookup · element lookup, periodic table element, atomic number lookup, element symbol lookup, atomic weight lookup |
Unpaid probe (census of )
| Field | Value |
|---|---|
| Probe | not probed in this build |
Latest re-probe
| Field | Value |
|---|---|
| Re-probed at | 2026-10-01T02:13:18.000Z (cron) |
| Verdict now | live changed from unprobed |
| HEAD / GET | 402 / 402 |
| accepts[0] | {"scheme":"exact","network":"eip155:8453","amount":"4000","payTo":"0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A","asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","maxTimeoutSeconds":300,"extra":{"name":"USD Coin","version":"2"}} |
| Live amount equals catalog price | yes |
| Latency | 5,034 ms |
| Error | none |
On-chain facts for the payTo (public address)
| Field | Value |
|---|---|
| Distinct payers | 5 |
| Payments | 197 |
| USDC volume | $1.35 |
| Median payment | $0.01 |
| First / last payment | 2026-09-09 / 2026-09-30 |
| Sampler-shaped share of payments | 100.0% |
| Payers that are not samplers | 0 |
| Source | forensics-2026-09-30 |
| Address | 0xb3f4de103F34b99f0Da19B4F16D6B53a14C2194A |
Declared input and output (extensions.bazaar)
{
"input": {
"body": {
"name": "example",
"symbol": "exa"
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
}
Try it (unpaid: shows the 402)
curl -si -X POST 'https://chem.openverbs.com/v1/element' -H 'accept: application/json' -H 'content-type: application/json' --data '{}'
The catalog declares POST. A 402 answer carries the payment requirements in the JSON body and, for x402 v2, base64 in the PAYMENT-REQUIRED header. This page never sends a payment.
Paid checks (x402, USDC on Base)
GET https://bazaar.agentexchange.work/r/abc7b3f2f475/probe.json re-runs this probe right now for $0.01 and writes the result here. POST https://bazaar.agentexchange.work/featured with {"id":"abc7b3f2f475"} places this resource at the top of the report and search pages for 30 days for $1.00, labelled. Unpaid requests answer 402 with the terms. Pricing.
Catalog references: agentic.market (CDP Bazaar front end) · this record as JSON · all resources on chem.openverbs.com.