Core concepts

LearnCoin is conceptually small. Five nouns carry most of the weight. Once you understand what each one is and how they fit together, the API surface is mostly obvious.

The five nouns

• Credential — a signed JSON-LD document describing an achievement. W3C Verifiable Credential 2.0 + Blockcerts v3 + Open Badges 3.0 simultaneously. Read on →
• Batch — a group of credentials issued together. The batch's Merkle root is what gets anchored on-chain. Individual credentials carry a proof that walks from their leaf up to that root.
• Anchor — the Ethereum L2 transaction (Base) that commits the batch's Merkle root. This is LearnCoin's trust substrate. Nothing about a credential depends on LearnCoin's servers; everything depends on the anchor transaction existing on Base.
• DID — the tenant's cryptographic identity. did:web:learncoin.me with per-tenant verificationMethod fragments. Issuer metadata is resolved via the DID document, which is served publicly.
• Verifier — any client that reads a credential's signed JSON-LD, resolves the issuer DID, walks the Merkle proof to the anchored root, and confirms the anchor transaction exists on-chain. LearnCoin publishes a reference verifier at learncoin.me/c/{id} that runs entirely client-side. Read on →

How they fit together

Issuer  ──POST /v1/batches──►  LearnCoin
                                  │
                                  ├─► Signs each credential with tenant key (GCP KMS)
                                  ├─► Builds Merkle tree from canonicalized credentials
                                  └─► Anchors Merkle root on Base → tx 0x…
                                  │
                                  ▼
                           Credential (signed JSON-LD)
                                  │
                                  ▼
                            Verifier reads document ─► resolves DID
                                                    ─► walks Merkle proof
                                                    ─► confirms anchor tx on Base
                                                    ─► five checks pass

What's next

• Credentials — what's inside a signed LearnCoin credential
• Verification chain — the five checks every verifier runs
• Glossary — 101 terms with their own URLs, for humans and AI agents