The vocabulary of verifiable credentials.

Achievement

The Open Badges 3.0 object that describes what a credential is for — its name, description, criteria, and skill alignments.

actualDuration

LearnCoin extension field recording how long a specific recipient actually took to earn a credential — distinct from OB 3.0 achievement.duration (the typical duration).

Alignment

An Open Badges 3.0 field linking an achievement to external skill frameworks — ESCO, O*NET, Lightcast, or custom.

Anchor transaction

The single blockchain transaction that commits the Merkle root of a batch of LearnCoin credentials to Base L2.

API key

A token that authenticates a tenant to the LearnCoin REST API, scoped to test or live mode and carrying tenant + permission metadata.

Auto-claim

A LearnCoin flag that lets tenants pre-authenticate a recipient and skip the magic-link email step, immediately marking the credential as claimed.

Awarding body

Also: credentialSubject.achievement.awardingBody

The Open Badges 3.0 field identifying the institution that actually granted the achievement — distinct from the cryptographic issuer.

Batch

A group of credentials signed and Merkle-anchored together in one LearnCoin issuance operation — economics of scale at the anchoring layer.

Bitstring Status List

Also: StatusList2021, W3C Bitstring Status List

A W3C-standardized compressed-bitstring credential that lets any verifier check revocation status without contacting the issuer's API.

claim_state

The LearnCoin field tracking whether a credential has been claimed by its recipient — pending, claimed, auto-claimed, expired, or consumed.

Credential Status

A mechanism that lets a verifier check whether a credential has been revoked without contacting the original issuer's API.

credentialSchema

A W3C VC 2.0 field pointing at an external JSON Schema describing the credential's data structure — lets verifiers check shape conformance.

Criteria

The Open Badges 3.0 narrative describing how an achievement is earned — what the recipient did to qualify.

difficulty

A LearnCoin extension field on achievements with the enum beginner / intermediate / advanced / expert — universally useful, not in OB 3.0.

Evidence

Supporting artifacts (submissions, recordings, portfolios) referenced from a credential to back up the claim.

Holder

The role in a W3C Verifiable Credentials flow that possesses a credential and presents it to verifiers — usually but not always the same entity as the subject.

Idempotency-Key

An HTTP header that lets LearnCoin's POST /v1/batches dedupe requests — two calls with the same key return the same batch ID.

Issuer

The party that creates and signs a verifiable credential — in LearnCoin, always did:web:learncoin.me with per-tenant verificationMethod fragments.

Magic-link claim

The LearnCoin email-based flow where recipients receive a one-time link that binds the credential to their email and marks it claimed.

Presentation

Also: Verifiable Presentation

A W3C VC concept where a holder bundles one or more credentials into a signed presentation to send to a verifier — the wallet-to-verifier unit.

Recipient

In LearnCoin parlance, the human who earned the credential — represented pseudonymously in the signed JSONLD and concretely in off-chain PII storage.

related_credentials

A LearnCoin extension field for linking credentials — reissue chains, team-challenge cross-references, replacement relationships.

result

An Open Badges 3.0 field recording a scored outcome on a credential — present in LearnCoin credentials as display metadata, pending full signing once the LearnCoin context publishes.

resultDescription

An Open Badges 3.0 array on the achievement that defines possible scored outcomes — the class-level counterpart to the instance-level result.

Revocation

An issuer's explicit withdrawal of a credential they previously issued — distinct from (and independent of) recipient-requested erasure.

Tenant

A LearnCoin customer — a university, employer, training platform — isolated at the database, key, and credentialing levels from every other tenant.

Verifiable Credential

Also: VC, W3C VC, VC 2.0

A digitally signed claim about a subject, issued by one party and independently checkable by any third party using open cryptography.

Verifier

The role in a W3C Verifiable Credentials flow that receives a credential and cryptographically checks it — can be a human, system, or AI agent.

Webhook delivery

LearnCoin's asynchronous event notification system — signed HTTP POSTs to tenant-registered URLs for batch.anchored, credential.claimed, credential.revoked events.