Arkham

What it is

A blockchain explorer where the addresses already have names on them. You search a person, a company or a fund rather than a hex string, and Arkham shows the wallets it has attributed to that entity, the balances behind them, the counterparties and the transfers in and out. Around that sit the pieces a research desk actually uses: alerts on an entity's movements, a Visualizer that draws fund flows as a graph, Tracer for following money between addresses, dashboards, and per-entity pages for exchanges, governments, funds and named individuals.

The labels are the product. Everything else here is an explorer, and free explorers are not scarce; what is scarce is the claim that a given address belongs to Coinbase, to a government, or to a named person. Arkham's engine, ULTRA, combines address clustering, behavioural modelling, ML heuristics and public off-chain signals, and publishes two grades: verified labels at a stated confidence threshold of 98% or better, and entity predictions at 80% or better, marked in the interface with a different badge.

Note what this card is not about. The same domain also hosts Arkham's own DEX and a prediction market front end; those are trading venues and this catalogue does not list them. The analytics product is separable — it has its own terms of service, its own privacy policy and its own API docs — and needs no funded account.

Pricing

Arkham publishes no pricing page for the analytics platform. /pricing, /plans and /upgrade are all 404s, and the billing screens redirect to a login. The platform is free to sign up for and much of it reads without an account at all. The application's own code carries plan language — "View Plans", "Upgrade Plan", "Cancel Subscription", plus a tier and an upgrade request on alerts — so paid platform tiers exist in some form; no number for one is public.

What is priced in the open is the Intel API, in its documentation rather than on a pricing page:

• Subscriptions are custom-built, usage-based in credits per month, and start at $100. Pay-as-you-go and bespoke plans are offered. Access is by request form, and Arkham says it replies with either a proposal or trial access.
• Trials give 100,000 credits on an individual account, 1,000,000 on an organisation account, and cap you at 10,000 unique labelled-address lookups per period. Hit the cap and API access pauses until you upgrade.
• Credits are not requests. Endpoints carry weights: one credit for a single address lookup, 30 for a search, 250 to 1,000 for the batch endpoints. /transfers and /swaps bill per row returned at 2 credits each, so a careless limit is the expensive mistake here.
• x402 sells the same endpoints one request at a time at $0.20 per credit, settled in USDC on Base or Solana, with no account and no API key. Per-row endpoints charge for the limit you ask for whether or not that many rows come back. Failed requests are not charged.
• Risk scoring — 0-to-100 exposure scores across categories such as sanctions, mixer and ransomware — is a paid add-on to an API subscription and in beta, not part of any standard tier.

Paying label limits also scale by account type: one million lookups per period on an individual plan, ten million per seat on an organisation plan.

Data & coverage

Arkham's own pages disagree about how many chains it reads: the API landing page says 16, the machine-readable API index on the same site says 20+, and the endpoint that would settle it needs a key. The chain identifiers the application itself carries include Bitcoin, Ethereum, Solana, Base, Arbitrum, Polygon, BNB Chain, Tron, Avalanche, Optimism, Dogecoin, Linea, Flare, Manta and Blast, plus HyperCore for perpetuals positions, balances, trades and PnL. Polymarket events, markets and prices are a separately advertised dataset.

Transfers stream into the explorer as they confirm, and the API offers a websocket alongside REST — v2 current, v1 deprecated. REST rate limits are 100 requests per second on ordinary endpoints and 1 per second on the heavy ones, which is most of what you would actually want in bulk: transfers, swaps, search, counterparties, flows, HyperCore trades and every batch endpoint. Batch lookups take up to 1,000 addresses per call, which is the intended way around that limit.

Attribution is explicitly a moving target by the vendor's own description: entities expand as new addresses are linked, and Arkham says attribution is corrected in rare cases. There is no published history depth anywhere in the documentation — no statement of how far back transfers or balances go on any chain.

Integrations

Alerts deliver to Telegram, Slack and webhooks. The API is REST plus websocket with an OpenAPI spec and a machine-readable documentation bundle, and the x402 endpoint exposes a catalogue with per-endpoint prices for agents that pay per call. Up to five API keys per account, one during a free trial.

There is no first-party MCP server. Arkham's guide for coding agents instead walks you through asking a model to generate a local MCP wrapper around the REST API and pasting it into a desktop client config — a fine trick, but it is your server, not the vendor's, and nobody maintains it when the API changes.

Limitations

The attribution is a judgement you cannot audit. This is the whole product and the whole problem with it. A verified label is published at a confidence threshold of 98% and a prediction label at 80%; the interface shows you a badge, not the clustering evidence, the off-chain signal or the analyst note behind it. You are asked to accept that a wallet belongs to a named person or company on Arkham's say-so, with no way to reproduce the finding and no correction log to read. Arkham's terms disclaim accuracy outright and put the risk of relying on the content on you. For a desk sizing a position that may be acceptable; for anything with a consequence attached to naming a person, it is not evidence.

Prediction labels look like facts on a screenshot. The badge distinguishing an 80%-confidence guess from a verified label does not survive being copied into a chat, a chart or a tweet, and that is how most of this data travels.

No published history depth. Nothing in the documentation says how far back any chain's transfers or balances go, which makes the platform hard to rely on for anything longitudinal.

The terms are restrictive even for a free product. Scraping, data mining and automated extraction are prohibited, as is copying, redistributing or building derivative works from the content — so anything you want to take out goes through a priced API key. Separately, employees, contractors and affiliates of any competing crypto analytics or blockchain intelligence company are barred from accessing the service at all without written permission.

Cost is hard to forecast before you sign. With no public platform pricing and API plans quoted per customer, the only number you can plan against without talking to sales is the x402 rate, and per-row billing on the transfer endpoints means the bill scales with the limit parameter rather than with what you got back.

Risk scores are a beta add-on, not a compliance product. Arkham says coverage is still expanding and that the model and response fields may change.

Alternatives

Nansen answers the same question — who is behind this address — and has the same structural problem: you are buying a judgement you cannot audit, and its labels carry no dates or history at all, where Arkham at least grades its confidence. Bubblemaps narrows the question to one token's holders and draws the transfers between them, which is the better instrument when what you want is a cluster rather than a name.

The honest alternative to all three is to build the attribution yourself: Dune and Allium sell indexed chain data as SQL, with no opinion attached and no label to take on trust. That costs a query you have to write and maintain, and it is the only version of this that you can show your working for.