®APIs that make the rest of your software possible.
We design, build, and integrate APIs that let your business systems talk to each other — Tally to your CRM, e-commerce to your ERP, your custom app to the world. Documented, observable, and built for scale.
When to hire us
- Your tools don't talk to each other
- You need a custom API for partners or internal apps
- You want a single integration layer instead of point-to-point chaos
- You're scaling and need APIs that won't fall over at 10×
What is custom API development?
An API (Application Programming Interface) is the standard mechanism by which software systems share data and trigger actions with each other. Custom API development means building these interfaces designed around your specific business logic — the data models, authentication patterns, and workflows that matter to your operation — rather than adapting your business to what a vendor's generic API allows. For most businesses, the more pressing need is integration work: connecting the tools and systems they already have so that data flows automatically between them, eliminating the manual synchronisation that wastes team hours and creates errors. A CRM that doesn't automatically sync with an e-commerce platform means someone is copying orders to a spreadsheet; a Tally instance that doesn't talk to a custom business system means someone is keying in figures by hand.
Nowgray builds both: custom APIs for businesses that need to expose their data or functionality to partners, mobile apps, or internal tools; and integration work that connects the stack you already have. Common projects include connecting Tally with custom software, synchronising Zoho or Salesforce CRM with a business-specific system, building Razorpay or Stripe payment integrations, creating ETL pipelines from legacy databases, and wiring WhatsApp Business API into a CRM or support workflow. For each integration, we build retry logic, error monitoring, and alerting so you know when something stops syncing rather than discovering it a week later.
Reliable APIs and integrations share three properties that are easy to skip in a first build: documentation, versioning, and observability. Documentation means your team and partners can understand how to use the API without asking the original developer. Versioning means you can change the API without breaking clients that depend on the current version. Observability means every API call is logged, traced, and alerted on — you know the error rate, the latency, and exactly which calls are failing. We include all three in every API project, because an API that isn't observable is one you can't debug when it behaves unexpectedly in production.
The capabilities, spelled out.
Custom API development
REST and GraphQL APIs designed around your business logic, not generic CRUD.
Third-party integrations
Tally, Zoho, HubSpot, Salesforce, Stripe, Razorpay, Shopify — and almost anything with an API.
Middleware & iPaaS
Zapier, Make, n8n, or custom — workflows that move data reliably, with retries and observability.
Documentation
Real OpenAPI specs, runnable examples, and Postman collections. APIs your team and partners can actually use.
Security & access
OAuth, API keys, JWT, rate limiting, IP allow-listing. Built for production, not demo.
Versioning & contracts
Backward compatibility, deprecation strategies, contract tests — change without breaking partners.
Our default stack.
We'll pick the right tools for your project — but if you don't care, this is what we usually reach for.
Outcomes, not just hours.
- All your systems sync in real-time — no more midnight CSV exports
- Partners and customers can integrate with your platform in hours, not weeks
- Clear observability — every call logged, traced, and alerted
- Source-controlled, documented APIs that survive team changes
Let's scope your connect your stack.
Tell us what you have in mind — we'll come back with a clear plan, timeline, and quote.