From field to shelf — provably.
PTrace lets a cooperative log every job in the field with photos and GPS, signs each entry on the phone, anchors the journal on Calix Chain, and prints a QR label so the buyer can see the whole story of the batch.
- Offline-first
- Ed25519 + ML-DSA-65
- Calix Chain
- QR
- VietGAP
Six steps, one chain of evidence
Nothing is retyped later. The record the farmer makes in the field is the record the buyer sees.
- LogSpraying, fertilising, watering, harvest — with photos and GPS, even offline.
- SignThe phone signs each entry with a key that never leaves the device.
- SyncSent automatically when there is a network; nothing is lost if it fails.
- AnchorA Merkle root of the journal is anchored on Calix Chain.
- SealHarvest becomes a batch; sealing freezes its entries and issues QR labels.
- ScanThe buyer scans the label and reads the journal, custody and chain proof.
Built for the field, not the office
Everything a cooperative needs from the first plot to the last pallet.
Offline farm journal
Record work with photos and GPS without a signal. Drafts autosave; “record again like last time” refills the form.
Pre-harvest interval alerts
Harvest too soon after spraying? PTrace warns you, based on the interval your cooperative set for each material.
Batches & QR labels
Group a season’s harvest into batches, seal them, print or share the labels, revoke a label if needed.
Chain of custody
Hand a sealed batch to a distributor with a signed handover. Each leg adds signed transport steps; the NFT passport moves with the goods.
Tasks & reminders
Recurring tasks, assignments, and a 7 a.m. reminder on the due day. Finishing a task means writing its journal entry.
Reports & VietGAP
Yield, material and cost reports, CSV export, and a printable VietGAP-style journal.
Screenshots show demo data from a test server — names, farms and figures are fictional.
A record nobody can quietly rewrite
Evidence is built in layers, so a buyer does not have to take the cooperative’s word for it.
Device-held keys
Each phone makes its own key and keeps it in the Keychain / Keystore. Entries are signed with Ed25519, and with ML-DSA-65 (FIPS 204) too when the post-quantum library is present, so the signature outlasts a quantum computer. Without the library the app falls back to Ed25519 alone.
Anchored on Calix Chain
The server anchors a Merkle root of the journal. The app shows “on-chain” only when the anchor is confirmed — never inferred from a field merely being present.
Sealed batches
Sealing happens once. The server freezes the batch’s entries, and the app refuses to seal while the phone still holds unsent entries for that scope.
No data lost on a bad network
Entries and photos stay in a local queue until the server accepts them. Re-sending is idempotent, so a retry never creates a duplicate.
ctx-sig-v3 | client_id | plot_id | entry_type | created_at_ms
| sha256(payload) | lat,lng | photo_hashes
→ Ed25519 + ML-DSA-65
The right access for each person
Owner, manager and field worker see and do different things. Partners such as distributors and supermarkets are organisations on PTrace too.
| Capability | Owner / manager | Farmer / technician |
|---|---|---|
| Write journal entries (offline, photo, GPS, signed) | ✓ | ✓ assigned plots |
| Review and flag entries | ✓ | — |
| Plots, seasons, materials catalogue | edit | view |
| Tasks | create, assign | do assigned |
| Batches: preview, seal, transport, QR labels, handover | ✓ | view |
| Members and permissions | ✓ | — |
| Reports, CSV, VietGAP journal | ✓ | ✓ |
Two-level approval is optional: a manager submits a batch, the owner approves. The owner can also seal directly.
Open a cooperative in minutes
Install PTrace on Android or iPhone, tap “New cooperative? Register free”, add your plots and invite your team. Buyers need no app — they just scan the label.