touchstone.locomot.io

Exact structured diff. mode=text -> unified diff + line counts; mode=json -> an RFC 6902 JSON Patch (RFC 6901 pointers) that round-trips a->b; mode=words -> inline word-level opcodes. For large inputs use POST. Every answer signed. Free sample, no payment required: GET /play/diff

Deterministic WMM2025 magnetic field (one location/date). Free sample, no payment required: GET /play/field

Deterministic readability scores (Flesch, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI) over published formulas. For long text use POST. Signed.

Timelock encryption (tlock / encrypt-to-the-future): seal a payload toward a future drand round — undecryptable by anyone, including us, until that round lands; or open a landed seal. For sealed-bid auctions, commit-reveal, scheduled secrets, dead-man switches. age-armored, interoperable. Free zero-knowledge inspect at /sealed/inspect.

Deterministic ephemeris snapshot (one location/time). Free sample, no payment required: GET /play/sky

Deterministic unit conversion reproducing NIST SP 811 exact factors (length, mass, volume, energy, power, pressure, force, area, speed, data, angle, frequency + affine temperature). Every answer signed. Free sample, no payment required: GET /play/unit

Deterministic phonetic rhyme (perfect + scored slant), pronunciation, syllables, scansion, homophones — from CMUdict. Free sample, no payment required: GET /play/prosody

Deterministic syntax validation — does this JSON/YAML/TOML/Python/regex parse? Valid/invalid + error location from the canonical parser. For long source use POST. Free sample, no payment required: GET /play/syntax

Deterministic time/timezone truth: DST-aware zone conversion, transition times, business-day & holiday math, epoch<->ISO. Free sample, no payment required: GET /play/time

Before you pay an x402 door, check it against its catalogue entry. A nightly probe of EVERY host in the x402 index (1,618 hosts, 15,227 listings, 100% coverage): the live 402's real payTo and price versus what the catalogue claims, plus dead and self-contradicting hosts. 28.6% of listings sit on a host the catalogue gets wrong — one names one payee and pays another across 965 listings. Free sample, no payment required: GET /play/door

Deterministic, rule-based proofreading flags — passive voice, adverbs, wordiness, filler, repeated words, whitespace, a/an, punctuation, sentence length, capitalization. Each flag carries an offset + suggestion. For long text use POST.

Provably-fair draw from the drand beacon with the full verifiable receipt + nonce-binding (the free draw is at GET /random).

Verifiable timestamp (trustless proof-of-existence / freshness proof): bind a hash to a drand round for an anti-backdating receipt — proves data existed no earlier than a public instant, with no trusted timestamp authority. Privacy: stamp an opaque sha256 digest.

Recover who signed a message (ecrecover, EIP-191 personal_sign). For EIP-712 typed data use POST /verify/sig. Every answer signed.