Building an API costs $5,000–50,000 (₹3–30 lakh) for typical business APIs, $50,000–150,000 for platform-grade APIs serving external developers, plus $50–500/month in infrastructure and 15–20% of build cost annually in maintenance. The price tracks one variable above all others: how many systems and how much business logic the API must orchestrate.
What APIs cost to build
- Simple CRUD API (₹3–6 lakh / $5,000–10,000): create-read-update-delete operations over one database — 3–5 weeks. The backbone of most internal tools.
- Business logic API (₹6–18 lakh / $10,000–30,000): workflows, validations, role-based access, third-party calls — the standard enterprise tier.
- Integration API (₹8–25 lakh): two or more systems synchronised — ERP to CRM, payment webhooks, logistics status — with the error handling and retry logic that integrations live on.
- Public product API (₹25 lakh–1 crore / $50,000–150,000+): external developers consuming your API — versioning, documentation, rate limiting, keys, developer portal. Platform territory.
REST versus GraphQL versus the pragmatics
REST remains the default: simple, cacheable, universally understood. GraphQL wins when clients need flexible shapes over complex data (mobile apps aggregating multiple resources). gRPC dominates internal service-to-service at scale. The honest guidance: choose REST unless a specific, articulable need says otherwise — every alternative buys power with complexity your maintainers inherit.
What drives the price
- Business logic depth — endpoints that move money, inventory or entitlements cost more than endpoints that move text
- Integrations — every external system brings auth schemes, rate limits, failure modes and documentation of varying honesty
- Authentication and permissions — API keys to full OAuth 2.0 with scoped tokens: a 2x spread
- Rate limiting and abuse protection — essential for anything public
- Documentation and SDKs — an API without docs is a rumor; budget 15–20% of build for real documentation
Integration costs (the hidden half)
Connecting to existing systems — SAP, Salesforce, Tally, custom databases — often costs as much as the API itself: ₹3–15 lakh per integration depending on the system's API quality (or absence of one). Legacy systems without APIs need wrappers built first; budget accordingly. This reality is why our custom software cost guide treats integrations as their own budget line, not a footnote.
Maintenance: the 15–20% law
APIs decay without care: dependencies retire, upstream APIs change, usage patterns stress designs. Annual maintenance of 15–20% of build cost covers version upgrades, security patches, monitoring and the evolutionary changes real usage demands. For customer-facing APIs, versioning discipline (never break a shipped contract) is the difference between an ecosystem and a mutiny.
Scoping an API properly
- Start from consumers: who calls it, from where, how often — the client list dictates the design
- Contract-first: specify endpoints and payloads (OpenAPI) before code; the spec becomes the documentation
- Error handling as a feature: every failure mode designed, documented, and returning useful messages
- Observability from day one: logging, metrics, tracing — an unmonitored API is an unsupportable one
Getting a number
Bring the systems to connect and the consumers to serve — the quote follows the orchestration, not the endpoint count. Our custom software development team scopes APIs contract-first; see the pricing or book a scoping call with your integration list.
Frequently asked questions.
How much does API development cost?
Simple CRUD APIs cost ₹3–6 lakh ($5,000–10,000), business logic APIs ₹6–18 lakh, integration APIs ₹8–25 lakh, and public platform APIs ₹25 lakh–1 crore. The main price driver is business logic depth and integration count, not endpoint count.
How much does API integration cost?
₹3–15 lakh per integration depending on the target system's API quality. Modern SaaS with clean APIs sits at the low end; legacy systems without APIs need wrappers built first, doubling the work. Error handling and retry logic are where integration budgets actually go.
REST or GraphQL — which should I choose?
REST by default: simple, cacheable, universally supported. GraphQL when mobile clients need flexible data shapes over complex graphs. gRPC for internal service-to-service at scale. Every alternative to REST buys power with complexity your team inherits permanently.
What is API maintenance and why does it matter?
Annual maintenance runs 15–20% of build cost: dependency upgrades, security patches, monitoring and evolution as usage grows. For public APIs, versioning discipline — never breaking a shipped contract — protects the developers who built on yours.
What documentation does an API need?
An OpenAPI specification as the contract, endpoint references with request and response examples, authentication guides, error catalogues, and quickstart code. Budget 15–20% of build cost — an API without documentation is functionality nobody can use.
Enjoyed this? Let's talk about applying it to your product.
