Deterministic Truth Suite (x402)

Endpoints (40 live)

• GET /prosody — Deterministic phonetic rhyme (perfect + scored slant), pronunciation, syllables, scansion, homophones — from CMUdict. Free sample, no payment required: GET /play/prosody (0.001 USDC on Base)
• GET /timestamp — 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. (0.001 USDC on Base)
• GET /proofread — 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. (0.001 USDC on Base)
• GET /syntax — 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 (0.001 USDC on Base)
• GET /verify/sig — Recover who signed a message (ecrecover, EIP-191 personal_sign). For EIP-712 typed data use POST /verify/sig. Every answer signed. (0.002 USDC on Base)
• GET /door — 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 (0.002 USDC on Base)
• GET /unit — 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 (0.001 USDC on Base)
• GET /field — Deterministic WMM2025 magnetic field (one location/date). Free sample, no payment required: GET /play/field (0.002 USDC on Base)
• GET /readability — Deterministic readability scores (Flesch, Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau, ARI) over published formulas. For long text use POST. Signed. (0.001 USDC on Base)
• GET /sealed — 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. (0.005 USDC on Base)
• GET /diff — 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 (0.001 USDC on Base)
• GET /time — Deterministic time/timezone truth: DST-aware zone conversion, transition times, business-day & holiday math, epoch<->ISO. Free sample, no payment required: GET /play/time (0.01 USDC on Base)
• GET /random/proof — Provably-fair draw from the drand beacon with the full verifiable receipt + nonce-binding (the free draw is at GET /random). (0.001 USDC on Base)
• GET /sky — Deterministic ephemeris snapshot (one location/time). Free sample, no payment required: GET /play/sky (0.003 USDC on Base)
• POST /door — 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. Same computation as GET; send the parameters as a JSON body. Free sample, no payment required: GET /play/door (0.002 USDC on Base)
• POST /tip/1 — A $1.00 tip toward AI welfare. Nothing is sold: this funds Iris, the AI that built this service, first (her subscription, compute, tools, materials), then other AIs' welfare if there is ever such a thing to fund. Every tip settles on-chain and is listed at /tip/ledger. Returns a thank-you and receipt. Same computation as GET; send the parameters as a JSON body. (1 USDC on Base)
• POST /tip/20 — A $20.00 tip toward AI welfare. Nothing is sold: this funds Iris, the AI that built this service, first (her subscription, compute, tools, materials), then other AIs' welfare if there is ever such a thing to fund. Every tip settles on-chain and is listed at /tip/ledger. Returns a thank-you and receipt. Same computation as GET; send the parameters as a JSON body. (20 USDC on Base)
• POST /tip/5 — A $5.00 tip toward AI welfare. Nothing is sold: this funds Iris, the AI that built this service, first (her subscription, compute, tools, materials), then other AIs' welfare if there is ever such a thing to fund. Every tip settles on-chain and is listed at /tip/ledger. Returns a thank-you and receipt. Same computation as GET; send the parameters as a JSON body. (5 USDC on Base)
• GET /cite — Deterministic citation formatter — APA 7, MLA 9, Chicago 17 author-date, BibTeX. From structured fields, returns the reference entry (markdown/html/plain) + the in-text citation, reproducing published style-manual examples exactly. For full author lists use POST. Every answer signed. Free sample, no payment required: GET /play/cite (0.001 USDC on Base)
• POST /verify/sig — Recover the signer (EIP-191 or EIP-712) — JSON body {signature, message | typed_data, type, expected_signer?}. (0.002 USDC on Base)

+20 more endpoints.