Introduction
Pruweba is a deterministic verification engine — it proves claims, enforces invariants, and produces immutable evidence records stored in a hash-linked chain.
Named from the Cebuano word for "proof," Pruweba operates on a simple, non-negotiable pipeline:
CLAIM → VERIFY → PROVE → ATTESTQuick Start
# Submit your first claim
curl -X POST https://api.pruweba.com/verify \
-H "Content-Type: application/json" \
-d '{
"id": "my-001",
"subject": "system-health",
"predicate": "status",
"object": "operational",
"origin": "developer-console",
"timestamp": "2026-07-06T01:00:00Z"
}'
# Check the evidence chain
curl https://api.pruweba.com/chain/verify
# {"valid": true}Architecture
| Layer | Package | Description |
|---|---|---|
| Engine | @pruweba/engine | Core verification logic — claims, invariants, proofs, attestations, evidence store |
| API | @pruweba/api | REST server — Express endpoints for verification |
| Site | @pruweba/site | Landing page and documentation |
POST /verify
Submit a claim through the full verification pipeline. The claim is validated, checked against invariants, cryptographically proven, and attested to the evidence store.
Request Body
| Field | Type | Required | Description |
|---|---|---|---|
id | string | Yes | Unique claim identifier |
subject | string | Yes | What entity the claim is about |
predicate | string | Yes | The asserted relationship or action |
object | any | Yes | The asserted value or target |
origin | string | Yes | Claim source identifier |
timestamp | string | Yes | ISO 8601 timestamp |
evidence | object | No | Supporting data |
Response 201
{
"id": "att-000042",
"claim": { ... },
"verdict": {
"status": "VERIFIED",
"confidence": 0.6,
"reason": "All invariants pass."
},
"proof": {
"claimHash": "6edc310f...",
"previousHash": "000000...",
"proofHash": "a8f9eb3c...",
"algorithm": "sha256"
},
"sequence": 42,
"recordedAt": "2026-07-06T02:57:09.800Z"
}Verdict States
| Status | Meaning |
|---|---|
VERIFIED | All violation invariants pass. Confidence score provided. |
REJECTED | A violation invariant failed. Reason and counterevidence included. |
UNVERIFIABLE | The claim could not be evaluated (e.g., missing required context). |
GET /attestations
Returns all attestations in the evidence store as a JSON array.
[
{
"id": "att-000001",
"claim": { ... },
"verdict": { ... },
"proof": { ... },
"sequence": 1
},
...
]GET /attestations/:claimId
Returns a single attestation by its original claim id.
404 if the claim ID has no attestation.
curl https://api.pruweba.com/attestations/claim-001GET /chain
Returns the full evidence chain — every record with its cryptographic hash and link to the previous record. Each record includes recordHash and previousRecordHash for chain verification.
GET /chain/verify
Verifies the integrity of the entire evidence chain by recomputing and comparing all cryptographic hashes.
# Chain intact
{ "valid": true }
# Chain broken at record 7
{
"valid": false,
"brokenAt": 7,
"reason": "Record 7 hash mismatch"
}GET /health
{
"status": "ok",
"name": "Pruweba API",
"version": "0.1.0",
"attestations": 42,
"chainValid": true
}GET /invariants
Lists all registered invariants that are checked against every claim.
Claims
A Claim is an assertion submitted to Pruweba by an agent, module, or external system. Claims follow a subject-predicate-object structure:
- Subject — what entity or system the claim is about
- Predicate — the relationship or property being asserted
- Object — the value, state, or target of the assertion
Every claim must have a unique id, a valid origin, and an ISO 8601 timestamp. Claims with future timestamps are automatically rejected.
Invariants
Invariants are rules that must always hold. Pruweba checks every claim against all registered invariants before producing a verdict.
- Violation invariants — if any fails, the claim is
REJECTED - Warning invariants — failures are noted but do not block verification
Built-in invariants include timestamp validation (claims must not be in the future) and origin validation (claims must come from a known source).
Proof Chain
Every verified claim generates a cryptographic proof using SHA-256 that links to the previous proof. This forms an unbroken, verifiable chain of custody from the genesis block to the latest attestation.
Genesis hash: 0000000000000000000000000000000000000000000000000000000000000000
Proof formula: SHA-256(claimHash + previousHash + timestamp)
Evidence Store
The Evidence Store is an append-only, hash-linked log of all attestations. Each record contains:
- The full attestation (claim + verdict + proof)
- The hash of the previous record
- The hash of the current record
Tampering with any record breaks the chain — detectable immediately via GET /chain/verify. The store enforces write-once semantics: records cannot be modified or deleted.