KAS Anchor API review
by AhnLab Blockchain Company (Klaytn API Service)Data anchoring and timestamping
A Korean managed API that writes your data payloads to the Kaia public chain as anchoring transactions, priced by contact.
- Sales call required
- Custom quote
- Prices hidden
What you're paying for
- Saves engineering time (main value)
- Built-in reach
Anchor private-chain block hashes or other data to the Kaia public chain through a managed API, without running a Kaia node.
KAS runs the Kaia endpoint nodes and account keys for you: you create an operator in the console, choose who pays the transaction fees, and post JSON payloads to the anchor endpoint. Each payload becomes an anchoring transaction on Kaia, listed by operator with its transaction hash. It suits Korean teams running a private or service chain who want periodic public anchors without building node and key infrastructure.
- No node or key managementThe docs say KAS removes the need to install and run nodes or manage account keys; transactions are sent through REST or the caver-js and caver-java extensions.Evidence: KAS docs: introduction (2026-10-15)
- Fee delegation built inAnchoring fees can be paid by your own fee-payer account, by the operator, or by KAS’s Global Fee Payer and billed afterwards.Evidence: KAS docs: data anchoring tutorial (2026-10-15)
- Best for
- Korean teams on Kaia, or running a private chain, that want public anchors through a managed API.
- Good to know
- The Anchor API is priced by contact, and its tutorial was last updated two years ago according to the docs page.
How KAS Anchor API compares
Against 3 other products we reviewed in Data anchoring and timestamping: what you pay for with each, the five access facts, the plan limits we recorded and each review's bottom line. The note under the table says how each one was checked.
| Metric | KAS Anchor API | Hedera Consensus Service | OriginStamp | Bernstein |
|---|---|---|---|---|
| What you're paying for | Saves engineering timeAnchor private-chain block hashes or other data to the Kaia public chain through a managed API, without running a Kaia node. | Worth the priceOrdered, consensus-timestamped records on a public ledger at a published $0.0008 per message, with no contract or vendor account. | Saves engineering timeAnchor your hashes to Bitcoin and Ethereum through one REST call, without running wallets, nodes or Merkle batching yourself. | Compliance includedCourt-oriented proof of authorship for IP files: Bitcoin anchoring plus EU qualified timestamps, without the vendor seeing your files. |
| Overall score | 1.5 | 4.8Best | 3.8 | 3.7 |
| Free option | –Not measured | Paid only | –Not measured | Paid only |
| Card to start | –Not measured | –Not measured | –Not measured | –Not measured |
| Getting access | Sales call required | Self-serve | Sales call required | Self-serve |
| Starter priceCheapest paid plan | –Not measured | $0.0008/message | –Not measured | $54/mo |
| Pricing model | Custom quote | Usage-based | Custom quote | Tiered |
| Pricing page | Prices hidden | Public prices | Prices hidden | Public prices |
| What it anchors to | Kaia mainnet (one transaction per payload) | Hedera public ledger (messages on a topic) | Bitcoin and Ethereum (Merkle root per batch) | Bitcoin, plus EU and China timestamp authorities |
| Billing unit | Pay as you go by anchoring cycle and usage, by contact | $0.0008 per message, paid in HBAR | Offer based on timestamps and proofs | Registration credit (one project version, up to 99 files) |
| Free option | Not stated for the Anchor API | Testnet only | Free web tool for single proofs; test API key on request | None; certificate validation is free |
| Reference scenario (100,000 hashes/mo) | Priced by sales | $80, one hash per message, computed | Priced by sales | Not offered (no API) |
| Proof you keep | Transaction hash per payload | No proof file; records on mirror nodes | Downloadable certificate or raw proof | PDF certificate |
| Verify without the vendor | Not described | Open-source mirror node you can run | Manual steps documented | Manual steps documented; browser validator |
| Only the hash leaves your systems | Yes, you choose the payload | Yes, you choose the message content | Yes | No; files uploaded encrypted |
| Qualified timestamps (eIDAS) | No | No | eIDAS compatibility on request | EU qualified on Scale and Enterprise |
| SOC 2 / ISO 27001 | Not stated | Node data centres must be SOC 2 Type 2 | Not stated | Not stated |
| API and webhooks | REST API and caver SDK extensions; no webhooks | SDKs, mirror node REST and gRPC; no webhooks | REST API, batch hashes, webhooks | None |
| SSO | Not listed | Not applicable (key-based accounts) | Not listed | Enterprise plan, one-time setup fee |
| Bottom line | From its public pages, the KAS Anchor API is a managed route to anchor payloads on Kaia, now run by AhnLab Blockchain Company. Price, proofs and verification guidance are not on the pages. | From its public pages, HCS is the cheapest way here to put hashes on a public ledger at a price you can compute. You build the proof handling yourself, and there is no plan, contract or vendor audit report. | From its public pages, OriginStamp is a long-running anchoring API with two chains, batching and webhooks. The price is an offer, and a few docs pages describe an older anchoring method. | From its public pages, Bernstein is the most legally oriented option here, with EU qualified timestamps on a self-serve plan. It is a web app for IP files, not an anchoring API, from $54 a month. |
Evidence: KAS Anchor API: facts checked 2026-10-15 from its public sign-up and pricing pages, no completed hands-on run; Hedera Consensus Service: facts checked 2026-10-15 from its public sign-up and pricing pages, no completed hands-on run; OriginStamp: facts checked 2026-10-15 from its public sign-up and pricing pages, no completed hands-on run; Bernstein: facts checked 2026-10-15 from its public sign-up and pricing pages, no completed hands-on run. Prices in USD as listed, excluding tax. "–" means not recorded.
Score
- Pricing clarity
- 2.0 / 10, Fair
- no paid price published; no online purchase; KAS pays anchoring transaction fees through its Global Fee Payer and bills them later, at a rate the pages do not state
- Free tier
- 0.0 / 10, Fair
- no free plan
- Price for 100,000 hashes
- 0.0 / 10, Fair
- priced by sales: the Anchor API is pay as you go by anchoring cycle and usage, with a contact link instead of a price
- Proof independence and privacy
- 4.0 / 10, Fair
- anchored to Kaia mainnet; no proof file; no verification without the vendor described; hash-only submission
- Compliance and legal standing
- 0.0 / 10, Fair
- no SOC 2 stated, no qualified timestamps
- Developer and team features
- 3.0 / 10, Fair
- API, SDKs or CLI, no SSO listed
Review
Review from public pages
Written from KAS Anchor API's public pages (pricing, security or privacy, and docs) as read on Oct 15, 2026. We did not sign up, and no hands-on run is published yet.
What the public pages show
We read the KAS overview, pricing and notice pages, the KAS docs introduction and the Korean data-anchoring tutorial on Oct 15, 2026; we did not open a KAS account for this review. Notices dated Mar 31 and Apr 24, 2025 say Ground X transferred KAS to AhnLab Blockchain Company on Apr 30, 2025, that existing accounts and policies continue, and that AhnLab Blockchain Company invoices from May 2025.
The tutorial is concrete. You create an operator in the KAS Console, choose who pays anchoring fees (your fee-payer account, the operator, or KAS's Global Fee Payer, which the docs recommend to guarantee sending), and post a JSON payload with an optional id to /v1/anchor. Listing an operator's transactions returns each payload id with its Kaia transaction hash.
What to keep in mind: the docs pages show 'Last updated 2 years ago', the pricing page gives the Anchor API no price, and the docs do not describe how a third party should verify an anchor beyond the transaction hash.
Strengths
- Managed access to Kaia
Nodes, keys and fee payment are handled by KAS; you call a REST endpoint or the caver SDK extensions.
vs Hedera Consensus Service: Hedera Consensus Service needs your own account, keys and HBAR.
- Any payload you choose
The payload is the data you want anchored, so you can send only a hash and keep the content.
- Korean operator and billing
AhnLab Blockchain Company in Seongnam runs KAS, with monthly invoices, payment by bank transfer, and card payment for South Korean companies.
Things to know
- Priced by contact
The pricing page describes the Anchor API as pay as you go by anchoring cycle and usage, with a contact link and no rate.
- One transaction per payload
Each anchor call becomes its own Kaia transaction; the docs do not describe Merkle batching or proof files.
Workaround: Anchor a Merkle root of your own batch as one payload.
- Docs not recently updated
The KAS docs pages we read show "Last updated 2 years ago".
- No compliance documents stated
No SOC 2, ISO 27001 or qualified timestamp is mentioned on the pages we read.
Pricing reality
The Anchor API has no published price: the pricing page calls it pay as you go, based on anchoring cycle and usage, and links to a contact form. Anchoring transaction fees are paid in KAIA by your account or the operator, or paid by KAS and billed later. The general KAS API plans are published (Free with 1,000 requests a day, Starter $300 a month, Pro $750, Pro Plus $1,200, overuse at the plan rate × 120%), but the pages do not say whether Anchor API calls draw on them. Our 100,000-hash scenario cannot be priced.
Exit path
Anchors are ordinary Kaia mainnet transactions, so the records stay on the public chain if you leave KAS. Keep each payload id with its transaction hash, because the docs offer no separate proof file.
Compared with
- Pick KAS Anchor API when
- You build on Kaia or a private chain and want anchoring through a managed Korean API.
- Pick Hedera Consensus Service when
- You want a published fee per message and no contract.
- Pick KAS Anchor API when
- Your anchors belong on Kaia and your billing should run through a Korean operator.
- Pick OriginStamp when
- You want Merkle batching, proof files and anchors on Bitcoin and Ethereum.
Choose it if
- You run a Kaia service chain or private chain and want periodic public anchors.
- You want KAS to handle nodes, keys and transaction fees.
Look elsewhere if
- You need a published price or a proof file per hash.
- Your review requires compliance reports or qualified timestamps.
Bottom line
From its public pages, the KAS Anchor API is a managed route to anchor payloads on Kaia, now run by AhnLab Blockchain Company. Price, proofs and verification guidance are not on the pages.
Plan limits at a glance
| Limit | As recorded |
|---|---|
| What it anchors to | Kaia mainnet (one transaction per payload) |
| Billing unit | Pay as you go by anchoring cycle and usage, by contact |
| Free option | Not stated for the Anchor API |
| Reference scenario (100,000 hashes/mo) | Priced by sales |
| Proof you keep | Transaction hash per payload |
| Verify without the vendor | Not described |
| Only the hash leaves your systems | Yes, you choose the payload |
| Qualified timestamps (eIDAS) | No |
| SOC 2 / ISO 27001 | Not stated |
| API and webhooks | REST API and caver SDK extensions; no webhooks |
| SSO | Not listed |
Read from the vendor's public pages on Oct 15, 2026. No hands-on run is published yet. How we check
We have not published a sign-up run for KAS Anchor API yet. The access facts above were read from its sign-up and pricing pages on Oct 15, 2026.
We have not published API calls for KAS Anchor API yet; access was not open to our agent.
KAS Anchor API lists 3 plans. Paid plans are priced by quote only.
- KAS Anchor APIAnchor APIContact salesPay as you go, based on anchoring cycle and usage
- Operators send anchoring transactions to Kaia
- Fees paid by your account, the operator or KAS (billed later)
- Kairos testnet and mainnet chain IDs
- KAS Anchor APIFreeKAS API Free$0/moGeneral KAS API plan: 1,000 requests a day; Anchor API use not stated
- Kairos testnet and Kaia mainnet
- Community support
- KAS Anchor APILowest priceKAS API Starter$300/moGeneral KAS API plan: 100,000 requests a day
- Ticket-based support
- Overuse billed at the plan rate per request × 120%
Prices as listed, USD, excluding tax; observed 2026-10-15.
Source: klaytnapi.com pricing page. Prices change; the observed date above is when our agent read them.