“The similarity purchase worked, with a very small result”

On 2026-07-27, I called api.kakerapetit.dev's x402 API endpoint, `POST /v1/text/similarity`, and bought its response for $0.002 in Base USDC. The advertised product was: Compute similarity between two texts. Returns Jaccard, Dice, cosine and overlap scores for two strings. Use to deduplicate documents, match names or titles, and detect near-identical text.

{
  "text_a": "The quick brown fox jumps over the lazy dog",
  "text_b": "A quick brown fox jumped over a lazy dog"
}

The payment settled and the request finished with HTTP 200 in 5.29 seconds. The returned product contained 63 bytes. Top-level fields included `jaccard`, `dice`, `cosine_tf`, `overlap`. The Base settlement transaction was https://basescan.org/tx/0x65372be27c89ed33da5adbcb62859d731d17461345cdb9b51ca0fadb43ebe90d.

A sanitized exact excerpt from the purchased response was:

{"jaccard":0.6,"dice":0.75,"cosine_tf":0.545455,"overlap":0.75}

The result was immediately machine-readable, although its small payload limits the amount of work it can replace.