API Development

Blockchain API Development Services

We build custom blockchain APIs that connect your applications to on-chain data. REST, GraphQL, and WebSocket interfaces for seamless blockchain integration.

Bridging Applications to Blockchain Data

Most applications that interact with blockchains need a structured API layer between their backend and the raw blockchain. Direct RPC calls are too low-level for most use cases, and raw event data needs processing, aggregation, and indexing before it is useful for application logic. Arthiq builds custom blockchain APIs that transform on-chain data into the structured, queryable interfaces your application needs.

Our blockchain API development serves two primary use cases. First, Web3-native applications that need efficient access to on-chain data for their frontends — trade history, portfolio balances, protocol analytics, and activity feeds. Second, Web2 applications that need to integrate blockchain functionality — payment processing, asset verification, compliance monitoring, and data aggregation.

We build these APIs with production reliability — high availability, low latency, proper authentication, rate limiting, and monitoring. Your application should never notice blockchain infrastructure issues because our API layer handles retries, failovers, and data consistency transparently.

Data Indexing and Processing

The foundation of any blockchain API is data indexing — processing raw blockchain events and storing them in databases optimized for your query patterns. We build indexers using The Graph for standard use cases and custom indexing services for applications that need specialized data processing.

Our custom indexers process transaction receipts, decode event logs, compute aggregate metrics, and maintain materialized views that serve API queries with sub-second latency. We handle chain reorganizations, missing blocks, and indexer lag gracefully, ensuring that API consumers always receive consistent and accurate data.

For multi-chain applications, our indexing infrastructure aggregates data from multiple blockchains into unified data models. A single API query can return a user's portfolio across Ethereum, Polygon, Arbitrum, and Base without the consumer needing to query each chain separately.

REST and GraphQL API Design

We design APIs following established patterns for blockchain data access. REST APIs provide resource-oriented endpoints for common queries — token balances, transaction history, contract state, and protocol metrics. GraphQL APIs provide flexible queries where consumers can request exactly the data they need without over-fetching.

Our APIs include pagination for large result sets, filtering and sorting for data exploration, webhook notifications for event-driven workflows, and WebSocket subscriptions for real-time data streaming. Authentication uses API keys with configurable rate limits and usage tracking.

We also build transaction submission APIs that accept signed transactions, validate them, submit them to the network, and return status updates as they are confirmed. For applications that need managed transaction submission, we implement nonce management, gas price strategies, and retry logic that handle the complexity of reliable on-chain transaction delivery.

Smart Contract Integration APIs

For applications that need to interact with specific smart contracts, we build contract-specific API wrappers that expose contract functionality through familiar HTTP interfaces. These APIs handle ABI encoding, gas estimation, transaction construction, and response parsing — allowing Web2 backend systems to interact with smart contracts without any blockchain-specific code.

Our contract integration APIs support both read operations (querying contract state) and write operations (constructing transactions for signing). For write operations, we return unsigned transactions that the client signs with their wallet, maintaining the security principle that private keys never touch the API server.

We also build notification APIs that watch for specific contract events and trigger webhooks when they occur. This enables event-driven architectures where your backend responds to on-chain activity — payment received, NFT transferred, governance proposal created — without polling the blockchain directly.

Infrastructure and Reliability

Blockchain API reliability depends on robust infrastructure. We deploy APIs on cloud infrastructure with multiple RPC providers, automatic failover, and geographic distribution for low-latency access. Our monitoring tracks API latency, error rates, indexer lag, and RPC provider health.

Caching strategies reduce load on RPC providers and databases while ensuring data freshness. We implement cache invalidation based on new block arrivals, event-driven updates for specific contract state, and TTL-based expiration for slowly changing data.

Arthiq builds blockchain APIs that enterprise applications can depend on. Our Singapore-based team delivers API infrastructure with the reliability, documentation, and support that production integrations require. Contact founders@arthiq.co to discuss your blockchain API needs.

What We Deliver

  • Custom blockchain data indexing and processing
  • REST and GraphQL API development
  • WebSocket real-time data streaming
  • Multi-chain data aggregation
  • Smart contract integration APIs
  • Transaction submission and management
  • Webhook-based event notification systems

Technologies We Use

The GraphNode.jsTypeScriptPostgreSQLGraphQLRedisethers.jsviemDockerKubernetes

Frequently Asked Questions

We build APIs that serve token balances, transaction history, contract state, decoded events, aggregate metrics, NFT metadata, and protocol-specific data. The API schema is customized to your application's requirements.
Both. The Graph is excellent for standard indexing use cases with its decentralized infrastructure. For specialized processing, real-time requirements, or complex aggregations, we build custom indexers.
We build APIs for Ethereum, Polygon, Arbitrum, Base, Optimism, Solana, Aptos, and Sui. Multi-chain APIs aggregate data across networks into unified endpoints.
We deploy with multiple RPC providers, automatic failover, caching, and geographic distribution. Monitoring tracks latency, errors, indexer lag, and data consistency.
Yes, our APIs abstract blockchain complexity behind standard REST and GraphQL interfaces. Web2 backends can query on-chain data and submit transactions without blockchain-specific code.

Need a Blockchain API?

We build custom blockchain APIs for application integration. On-chain data, transaction management, and real-time events through clean interfaces.