API development · Three Index

APIs and integrations that don't break.

REST and GraphQL APIs, webhooks and third-party integrations designed for versioning, observability and the failure modes vendors actually have.

Team
50+ IT professionals
Delivery
Design, build, release, support
Engagement
Project or dedicated team

What this covers

Concrete work we take on under api development — not a catalogue of buzzwords.

  • Public and private API design
  • Payment, CRM, EHR, logistics and accounting integrations
  • Webhook systems and event-driven sync
  • API documentation and partner onboarding

Problems we take on

If one of these sounds familiar, we have likely shipped something close — and we will say so if we have not.

  • Systems do not talk to each other without manual CSV work.
  • An integration fails silently when a vendor changes a field.
  • Partners need a stable API and you do not have one.

Technologies

Stacks we use when they fit the product and your team — not a mandatory toolkit for every engagement.

  • Node.js
  • Python
  • GraphQL
  • REST
  • OpenAPI
  • Queues

How we work

  1. Scope before code

    We write what is being built, what is excluded, integrations, dates and cost basis before the build starts. Changes get quoted before they get coded.

  2. Talk to the people doing the work

    You meet named engineers and designers. There is no account manager translating technical questions in both directions.

  3. Working software every two weeks

    Increments land on staging you can open and use. Progress you can click on beats progress in a status report.

  4. You own everything

    Repository, cloud account, domains and credentials stay yours. We work in your accounts wherever possible.

FAQ

Can you integrate with our ERP/EHR?

If it has an API or a documented exchange format, yes. We will say early if vendor access is the blocker.

Do you provide API docs?

Yes — OpenAPI or equivalent, written for the people who will call it.

REST or GraphQL?

We choose based on clients and change patterns. Many products use REST; GraphQL fits when consumers need flexible queries.

How do you handle vendor failures?

Retries, idempotency, observability and clear failure modes — integrations that break silently are not acceptable.

Can you build partner-facing APIs?

Yes — versioned public or partner APIs with auth, rate limits and documentation for the teams that will integrate.

Related

Services that often sit beside api development on the same roadmap.

Industries we ship in · Case studies

Why Three Index

Founded in 2020 in Ahmedabad, Gujarat. Fifty-plus IT professionals. More than five hundred projects shipped across product and enterprise work.

We are large enough to staff serious products and small enough that the people who wrote a module can still explain it. See how we operate, browse case studies, or join the team.

Tell us what you are trying to build.

Send a short description of the project. You will get a reply from someone technical — with questions worth answering, not a brochure.