Currencyinfo 4.2.0: Reliable Reference Rates, Now Built for Everyone

A rebuilt multi-source engine, hardened distribution, living documentation, and a clearer home for developers who would rather own their rate infrastructure than rent another black box.

Every wallet, explorer, payment service, accounting tool, and portfolio app eventually asks a deceptively simple question: what is this asset worth right now?

The difficult part is not making one API call. It is deciding which source to trust, normalising unlike markets, surviving quotas and outages, rejecting bad data, preserving history, and explaining why the number changed. That is the work Currencyinfo has been designed to do.

A reference rate should not be a mysterious number borrowed from a single provider. It should be an observable result produced by rules you control.

Today, we are releasing Currencyinfo 4.2.0 and introducing a substantially renewed currencyinfo.dev. Together, the release and the website mark an important step: Currencyinfo is no longer presented as an internal ADAMANT component. It is a universal, open-source, self-hosted reference-rate service for anyone building with crypto and fiat data.

One service, multiple points of view

Single-source pricing is convenient until that source throttles requests, drops a market, changes its format, becomes unavailable in your region, or simply reports an outlier. Currencyinfo 4.2.0 approaches the problem differently: it can cross-check up to ten independent providers and turn their quotes into one configurable reference rate.

The release adds four keyless connectors: CoinPaprika, CoinLore, Binance, and ExchangeRate-API. Together with Currency API, the default configuration now has five sources that work without API credentials. CoinGecko remains available with a Demo key; CoinMarketCap and ExchangeRate.host support authenticated setups; MOEX provides another specialised option. CryptoCompare is retained for compatibility but is now deprecated and disabled by default because new access requires a subscription.

This breadth matters, but the goal is not to collect the largest possible list of logos. Providers differ in asset coverage, update frequency, regional availability, quotas, and market assumptions. Currencyinfo makes those differences explicit, then gives operators the controls to decide how they should affect the final rate.

From quotes to a defensible rate

The redesigned website summarises the pipeline in five stages:

1. Sources are polled on their own schedules.
2. Validation normalises pairs and rejects zero or non-finite cross rates.
3. Aggregation detects divergence, applies groups and weights, and uses minSources to decide whether a pair has enough support to publish.
4. History stores snapshots in the operator’s own MongoDB.
5. REST API exposes current and historical rates through focused endpoints.

That short description hides several useful controls. Authoritative source groups can be separated from fallback groups. Weights and merge strategies can express how providers should be combined. Deterministic base-coin triangulation can derive a pair when a direct quote is unavailable. Freshness handling through rateLifetime prevents stale observations from silently looking current.

Most importantly, minSources is now freshness-aware. A configured provider that has stopped delivering usable data no longer counts merely because it exists in the configuration. The service publishes when enough current evidence exists, and degrades predictably when it does not.

Resilience is not pretending every provider is always healthy. It is knowing which evidence is current, which is missing, and what your system should do next.

A release for operators, not only API consumers

Currencyinfo 4.2.0 also strengthens the parts that sit behind the endpoint.

Three date-ordered ticker indexes make history queries more practical at scale. In the release validation dataset of roughly 238 million documents, one representative pair-and-range query improved from 22.8 seconds to 8 milliseconds. Real results will depend on hardware, data distribution, cache state, and query shape, but the direction is clear: accumulated history is now far easier to use operationally.

The service has moved to Node.js 22.12 or newer and updates its platform to NestJS 12, Mongoose 9, Zod 4, TypeScript 6, and Jest 30. The completed test suite covers 28 suites and 266 tests.

Container distribution is now a first-class release surface. Images are published for linux/amd64 and linux/arm64 with OCI metadata, an SBOM, and build provenance. The runtime is non-root, package managers are removed from the production image, logs use restrictive permissions, secret-shaped values are redacted, and the CI pipeline includes vulnerability scanning.

For a new deployment, the shortest path is the public image:

docker pull ghcr.io/adamant-im/currencyinfo:4.2.0

A website that explains the product honestly

The new currencyinfo.dev is not simply a fresh coat of paint. It makes the product legible to people encountering it for the first time.

The first screen now names the audience and the job: self-hosted crypto and fiat reference rates for wallets, payments, and backend services. Clear links lead to the documentation, source code, releases, and public Docker package. A working request and JSON response show the API directly. The architecture section explains how data moves from providers to validation, aggregation, local history, and REST.

The update also improves semantics and accessibility: one page-level heading, a logical hierarchy, descriptive link names, meaningful image alternatives, keyboard-visible focus, and sharing metadata designed for the actual product. Like Currencyinfo itself, the site adds no analytics or third-party telemetry.

ADAMANT remains visible for an important reason: we use Currencyinfo in production and continue to steward its development. But the project is not limited to ADAMANT. It is equally relevant to an independent wallet, a block explorer, a payment backend, an accounting system, or an infrastructure operator who wants a rate service that can be inspected, configured, and run locally.

Clear boundaries are part of reliability

Currencyinfo produces reference rates. It is not an exchange execution feed, a high-frequency market-data terminal, or a hosted API with a guaranteed SLA. Self-hosting gives you control over configuration, history, privacy, and availability; it also makes you responsible for monitoring your deployment and respecting each upstream provider’s terms, limits, and redistribution rules.

Upgrading from 4.1.2 deserves planning. Older stock configurations may enable providers that now require credentials, so operators should disable those sources, add keys, or adopt the new keyless defaults before starting 4.2.0. Large existing history databases should also build the three new indexes out of band: the release measurements took about 17 minutes on NVMe storage and 50 minutes on SATA. Stored document formats remain compatible, which keeps rollback straightforward.

There is one more behavioural correction to note: history filters now use the documented BASE/QUOTE pair order. Clients that previously compensated by reversing pairs should remove that workaround. Unknown query parameters are also rejected with HTTP 400 instead of being silently ignored.

Build on rates you can understand

Currencyinfo 4.2.0 is a release about independence in the practical sense: more usable sources without mandatory keys, clearer aggregation rules, better failure behaviour, faster history, safer containers, and documentation that treats operators as first-class users.

If your product needs crypto and fiat reference rates, you can now evaluate the architecture in minutes, start from a public multi-architecture image, and keep the service and its history under your own control.

Explore the new website: currencyinfo.dev
Read the documentation: currencyinfo.docs.adamant.im
See the release: Currencyinfo v4.2.0
Inspect the work: release PR #58, documentation and positioning PR #53, release issue #56, and website issue #51.

Currencyinfo 4.2.0: Reliable Reference Rates, Now Built for Everyone was originally published in ADAMANT on Medium, where people are continuing the conversation by highlighting and responding to this story.