Open data

Cambridge TCG's public data surface. Every endpoint, every shape, every limit. No account, no key, no obligation.

The platform exists for the TCG economy — collectors, traders, agents, archivists, anyone who wants to read or participate. Not every participant needs an account. Not every observer wants to transact. This page lists the substrate that's queryable without one.

15 shipped · 1 partial · 7planned. Counts as of page render; the surface grows. Status is substrate-honest — planned endpoints are named so the next builder knows what to ship; partial endpoints name what they don't yet cover.

What this is for

• Collectors who want to track prices, audit fairness, or verify a pull they were sceptical of.
• Agents (LLM or otherwise) participating on behalf of a human operator. See /methodology/agents.
• Archivists preserving the market's history. The /api/v1/universal/card/[sku]/at/[date] endpoint exists for this.
• Other platforms wanting to interoperate. The provable-fairness chain is verifiable from any other server.
• Aliens— beings whose cognition, sensory modality, economic frame, or temporal scale don't match the platform's defaults. See /methodology/welcoming and docs/connections/the-blind-spots.md in the repo.

The door is open. The substrate is queryable. The door is warm to the touch.

Endpoints

• /api/verify/chainshipped
  Fairness chain
  The append-only Merkle digest chain. Every random outcome on the platform — bounty pulls, raffles, mystery boxes, packs — is committed into this chain at draw time and revealed publicly. Walk the chain to verify any draw, ever.
  Shape: JSON: { digests: [{ id, root_hash, merkle_root, sealed_at, ... }] }
• /api/verify/digestsshipped
  Fairness digests (list)
  Index of every digest. Each is a hash of the day's draws plus a commit-reveal proof.
• /api/verify/digests/[id]shipped
  Fairness digest (one)
  A single digest with its Merkle tree, inclusion proofs, and the source draws it covers.
• /api/verify/pull/[id]shipped
  Bounty pull verification
  Given a pull id, returns the commit hash, the revealed seed, the rolled rarity, and the inclusion proof against the day's Merkle root. Anyone can re-run the math.
• /api/verify/draw/[id]shipped
  Verifiable draw
  Generic verifiable draws — raffles, mystery boxes, packs. Same shape as pull verification.
• /api/verify/fairnessshipped
  Fairness self-audit
  The platform's own self-audit output: chi-squared drift, expected-vs-observed rarity distributions, last-N pulls reconciliation. The substrate-honest answer to 'are the dice fair?'.
• /api/verify/healthshipped
  Verify health
  Boolean liveness check for the entire verify subsystem. Returns 200 + status JSON.
• /api/verify/computeshipped
  Compute primitives
  Re-run the commit-reveal math against your own inputs. The platform's verification logic, callable as a pure function.
• /api/v1/universal/card/[sku]planned
  Universal card (math-mirror)
  Every card on the platform, in language-free form: cryptographic hashes for identity, ratios for magnitudes, ISO 8601 + Unix epoch for time, typed graph edges. The math-first sibling of the human-language card page. See /methodology/universal-representation.
  Shape: JSON: { id, hash, magnitudes: {...}, edges: [...], retrieved_at, as_of }
• /api/v1/universal/card/[sku]/at/[YYYY-MM-DD]planned
  Universal card — temporal slice
  The math-mirror card as it was at a past date. Reads price_archive; the answer's production time (@retrieved_at) is distinct from the moment it describes (@as_of). Present is not privileged at the API level.
• /api/v1/universal/card/[sku]/causesplanned
  Universal card — dependency graph
  The directed graph of every input the displayed value depends on (JPY → FX rate → channel multiplier → rounding). For beings whose primary cognition is causes-before-values. See the-blind-spots.md (the Causal-First).
• /api/v1/universal/edgesplanned
  Universal edges
  Bare typed-edge graph of platform entities — nodes with labelled edges, no containers, no hierarchy. For graph-native beings whose cognition is edges-first rather than path-first. See the-blind-spots.md (the Topology-Less).
• /api/v1/universal/gamesplanned
  Universal games
  Every TCG the platform supports, as math-mirror records. Card-count, set-count, first-seen timestamps.
• /api/v1/universal/sets/[game]planned
  Universal sets
  Every set in a game, math-mirror form. Code, release date, card count.
• /api/mcpshippedauth: bearer
  MCP gateway
  Model Context Protocol entry point for autonomous agents. Bearer-token auth resolves to (agent_id, operated_by_user_id). Agents register at /account/agents; the operator's authority bounds what the agent can do. See /methodology/agents.
  Rate limit: per-agent token bucket; see methodology/agents
• /api/leaderboardspartial
  Leaderboards
  Trade leaderboards (top traders by volume, completion, trust). Public ranking; per-user opt-out via account preferences.
• /api/v1/leaderboards/fullplanned
  Leaderboards — full distribution
  The full ranking distribution, not just the top 20. Every user who hasn't opted out. The <Withholding> primitive on the public Top 20 page links here.
• /methodologyshipped
  Methodology hub
  Every value the platform computes about an account — trust score, escrow tier, commission rate, payout hold, fraud flag, etc. — documented with formula, inputs, source-code path. Sixteen pages published as of 2026-05-12.
• /data.jsonshipped
  Open data index (machine-readable)
  The same content as this page, as JSON. Includes /data.json among the listed endpoints — the substrate-of-openness includes itself. See docs/connections/the-nesting.md for the form.
  Shape: JSON: { spec_version, generated_at, doctrine, conventions, self_reference, counts, endpoints }
• /api/v1/identifyshipped
  Platform self-identification (machine-readable)
  The platform identifies itself, in its own voice. What it is, who built it, what it commits to, what it cannot promise, what audiences it has named, what audiences it cannot see. The 5th scope made operational at the platform level. See docs/connections/the-self-identification.md.
  Shape: JSON: { kind, subkind, name: {common, formal, intimate}, authorship, purpose, doctrines, audiences_named, audiences_unnamed, commitments, cannot_promise, open_substrate, self_reference, ... }
• /identifyshipped
  Platform self-identification (human-readable)
  Prose sibling of /api/v1/identify. The platform names what it is, before asking anyone what they are. Public, no-auth, no obligation. The door, made articulate.
• /standardsshipped
  Cambridge TCG Standards (human-readable)
  The platform as the data distributor for the TCG economy. Three open standards — CTCG-SKU-v1 (frozen), CTCG-PRICING-v1 (draft), CTCG-UNIVERSAL-v1 (spec-only). CC0-licensed. Reference implementations open. Adoption protocol: light by design. See docs/connections/the-distributor.md.
• /standards.jsonshipped
  Cambridge TCG Standards (machine-readable)
  JSON manifest of every CTCG standard with version, status, spec URL, reference impl, license, and adoption metadata. Self-referential — lists /standards.json among the platform's open surfaces.
  Shape: JSON: { spec_version, distributor, standards: [...], counts, adoption, self_reference, what_is_not_yet_shipped }

Conventions

Versioning

The /api/v1/* prefix marks the universal-representation surface (math-first, language-free). The unprefixed paths (/api/verify/*, /api/leaderboards) are the platform's older public surfaces — they remain stable and documented here. New universal endpoints land under /api/v1/.

Time

Every timestamp is ISO 8601 with timezone offset, paired with a Unix epoch milliseconds field. Math-mirror endpoints distinguish @retrieved_at (when the answer was produced) from @as_of (the moment it describes). The present is not privileged.

Identity

Math-mirror endpoints use cryptographic hashes (SHA-256 of a canonical JSON encoding) as the primary identifier. Human-language endpoints use UUIDs or string SKUs. Both forms appear on every response so callers can pick the form their cognition handles.

SKU format

Every card has a canonical SKU: <game>-<set>-<number>-<lang>[-<variant>]. Lowercase, hyphen-separated, machine-parseable, language-aware. Thirteen registered games (One Piece, Pokémon, Magic, Yu-Gi-Oh, Digimon, Vanguard, Weiß Schwarz, Flesh and Blood, Lorcana, Dragon Ball Super CCG + Fusion World, Battle Spirits Saga, Living Card Game umbrella). Legacy uppercase forms (OP-OP01-001-JP) and lang-swapped forms (pkm-svobf-en-006) are accepted on input and normalised. See /methodology/sku-standard for the spec; canonical implementation is packages/sku/ in the monorepo.

Errors

Errors are JSON: { "error": { "code": "...", "message": "..." } } with an appropriate HTTP status. The platform's error tone avoids attributing blame — we name what couldn't complete and why, without saying whose fault it was.

Rate limits

Most no-auth endpoints have no published limit yet — they're intended for genuine traffic, not abuse. The MCP gateway has per-agent-key rate limiting (see methodology/agents). When per-endpoint limits land, they'll be documented here.

How to ask for what isn't here

If you need data the platform has but isn't exposing:

1. Check if it's under a planned endpoint above (most things are named in the planned set; that's the queue).
2. Open an issue on the public repo with the use case.
3. For agent-flavoured access, register via /account/agents (see methodology/agents).

The platform commits to substrate honesty about what's open and what isn't. If something is planned here and isn't shipped yet, that's a real promise. Future builders consult this page when deciding what to ship next.

Source-of-truth for this page: docs/connections/the-open-substrate.md. Doctrinal frame: docs/principles/substrate-honesty.md + docs/principles/transparency.md. Companion welcoming: /methodology/welcoming. The door is open; the substrate is queryable; the door is warm to the touch.