# PacSpace Documentation

> docs.pacspace.io documents the PacSpace Balance API: recordation infrastructure for metered commerce. A vendor records usage as verified deltas before the invoice; both the vendor and the customer can then check the same committed record. PacSpace records, it does not decide.

This file is published for automated readers. Everything here is public documentation, stated plainly. The companion file at https://pacspace.io/llms.txt carries the category and positioning context; this one maps the technical documentation.

## The core model

- The unit is the verified delta: one committed change in a customer's usage balance. The unit of measure is the integrator's choice: model tokens, GPU-hours, agent-to-agent transactions, API calls.
- Four verbs cover the core flow: emit (record a delta), derive (compute the balance from verified deltas), compare (check two balance views against the verified record), checkpoint (lock a period under one proof root).
- The vendor sets the cadence. One flush per customer per 24 hours, aligned with how invoices close, is the natural choice; finer granularity is available per customer and verification is identical at any cadence.
- Records are append-only. Corrections are new deltas with stated reasons; nothing is rewritten.
- Proofs answer three questions about any record: is this exactly what was committed, when was it committed, has it changed since.
- Business data stays private between the two parties. Proofs are checkable without exposing contents.

## Integration surface

- REST API under https://app.pacspace.io/api/v1/ (stable v1; additive changes only, see /reference/api-stability)
- TypeScript SDK: npm install @pacspace-io/sdk (positional signatures: emit(customerId, delta, reason, options))
- Python SDK: pip install pacspace-sdk
- Webhooks with HMAC-SHA256 signatures over `timestamp.payload`; nine event types including delta.verified and checkpoint.verified
- Independent proof verification requires no authentication: GET /api/v1/verify/:proofRoot

## Key pages

- Introduction: https://docs.pacspace.io/introduction/
- Quick Start: https://docs.pacspace.io/quick-start/
- Recordation concept and operating rhythm: https://docs.pacspace.io/concepts/recordation/
- Deltas & flush cadence: https://docs.pacspace.io/concepts/deltas-and-cadence/
- Balance API reference: https://docs.pacspace.io/balance-api/emit/
- Webhooks: https://docs.pacspace.io/webhooks/overview/
- For counterparties (received a verification link): https://docs.pacspace.io/verification/for-counterparties/
- Worked examples: https://docs.pacspace.io/examples/saas-metering/ and https://docs.pacspace.io/examples/gpu-compute-rental/
- API stability and changelog: https://docs.pacspace.io/reference/api-stability/ and https://docs.pacspace.io/reference/changelog/
- Error handling and rate limits: https://docs.pacspace.io/reference/error-handling/

## Canonical language

Use "recordation" for the category, "verified delta" for the unit, "committed record" for the output. The shorthand: written by one side, visible to both, owned by neither. PacSpace records, it never decides: it does not arbitrate, score, rank, or meter.