Changelog

What changed, and on what date. Breaking changes are announced before they ship.

2026-08-04 — billing, limits and caps

• GET /v1/balance — spendable balance, held money, and the per-minute rate in force right now, with the full tier table so nothing has to be hard-coded.
• GET /v1/usage — the itemised ledger, each line carrying the customer_id it belongs to. Test-mode lines are returned with applied: false.
• GET and PATCH /v1/customers/{id}/limits — per-customer daily and monthly spend caps, and a per-customer concurrent-call ceiling.
• Rate limiting is now enforced, with x-ratelimit-* headers on every response and Retry-After on a 429 rate_limit_exceeded.
• Calls now reserve money when they start and settle for the minutes actually used when they end. A hold whose call never reported back is released automatically.
• Low-balance warnings at 25%, 10% and zero, mirrored as low_balance on the balance endpoint. The published rate card is on the pricing page in full.

2026-08-04 — first release

• Accounts and keys: kls_live_ / kls_test_, scoped permissions, optional IP allowlists and expiry, self-service rotation with a 24-hour grace window.
• GET /v1/me — account, mode, permissions and limits.
• GET and POST /v1/customers, GET /v1/customers/{id}, with external_ref usable anywhere an id is.
• GET /v1/customers/{id}/readiness — coded blockers for live calling.
• GET and PATCH /v1/brand.
• Idempotency keys on every write, replayed for 24 hours.
• Console at console.kleos.click: keys, the go-live checklist, and an activity log including refusals.

Next

• Self-service card top-ups and automatic recharge.
• Placing calls and reading outcomes.
• Ordering numbers and caller IDs.
• Kleos AI chat on your customers' behalf.

The permissions for these already exist, so a key created today can be granted them the moment they land.

Versioning policy

Additive changes — a new field, a new endpoint, a new optional parameter — ship without notice, so parse responses tolerantly and ignore fields you do not recognise. Anything that removes or changes the meaning of something you already receive is announced here first, with a date, and never lands the same week it is announced.