Software Development
API Development and Integration Services
Well-documented APIs for your products and partners, and integrations that move data between your ERP, CRM, payment gateway and other tools without anyone retyping it.
- 01REST API design and development
- 02GraphQL APIs
- 03ERP and CRM integration
- 04Payment and commerce integrations
- 05Integration middleware
- 06Webhooks and event-driven integration
- 07API security and gateways
- 08Integration monitoring and support
At a glance
API development and integration means designing APIs your apps and partners can build on, and connecting the systems you already run so data moves between them without retyping. It's for companies whose ERP, CRM, online store and payment tools don't talk to each other. Tag4 Technology Solutions builds REST and GraphQL APIs, and integrations with retries, monitoring and alerts.
Updated
- Best for
- Companies re-keying data between ERP, CRM, e-commerce and payment systems
- Typical timeline
- 3–6 weeks per integration; 3–6 months for a hub or new API platform
- Typical budget
- $15k–$50k per integration; $60k–$200k for hubs and API platforms
- Systems we connect
- Dynamics 365, Business Central, NetSuite, Salesforce, HubSpot, Stripe, QuickBooks
- Core technologies
- OpenAPI, GraphQL, ASP.NET Core, Node.js, Azure API Management
- Offices
- New York, Chicago, Dallas, Toronto, Sydney, Dubai
Plenty of companies don't have a software problem so much as a plumbing problem. Orders arrive through Shopify, get re-keyed into the ERP, and someone emails a spreadsheet to finance every Friday. Our API development and integration services fix that plumbing. We design APIs your own apps and partners can build on, and we connect the systems you already pay for so data moves between them on its own.
Integrations break in predictable ways. A vendor changes their API without notice. A sync job fails at 3 a.m. and nobody finds out until a customer complains. Two systems disagree about what a customer ID is. Rate limits get hit during month-end close. We plan for all of it: retries with backoff, idempotent operations so a replay doesn't create duplicate orders, dead-letter queues for records that need a human, and alerts that reach a person instead of an unread inbox.
For new APIs, we write the contract first, usually an OpenAPI spec for REST or a schema for GraphQL, and review it with the teams who'll consume it before building anything. Arguments about naming and pagination are cheap at that stage. REST is our default for public and partner APIs because it's easier to cache, secure and document. GraphQL earns its place when many front ends need different slices of the same data.
A single integration between two well-documented systems often takes 3–6 weeks. A new API platform, or a hub linking five or more systems, is more commonly a 3–6 month project. Common systems we connect include Dynamics 365, Business Central, NetSuite, Salesforce, HubSpot, Stripe, QuickBooks and the usual shipping, tax and payment providers.
What we do
API Development & Integration services
REST API design and development
Versioned, documented APIs with consistent errors, pagination and authentication, built against an agreed OpenAPI contract.
GraphQL APIs
Schemas and resolvers for apps where several front ends need flexible queries, with query cost limits so one client can't overload the server.
ERP and CRM integration
Two-way sync between Dynamics 365, Business Central, NetSuite, SAP Business One, Salesforce or HubSpot and the rest of your stack.
Payment and commerce integrations
Stripe, Adyen, PayPal, Authorize.net, Shopify and tax services like Avalara, with webhook handling that survives retries and outages.
Integration middleware
Azure Integration Services, AWS messaging or a lightweight custom hub, chosen by transaction volume and the number of systems involved.
Webhooks and event-driven integration
Publishing and consuming events so systems react within seconds instead of polling every few minutes.
API security and gateways
OAuth 2.0, scoped API keys, rate limiting and gateway setup with Azure API Management or AWS API Gateway.
Integration monitoring and support
Dashboards and alerts for failed syncs, plus runbooks so your team knows what to do when a partner's API goes down.
How we work
What you can expect from us
Contract before code
Every consuming team signs off on the API spec before we build. Changing a document is cheaper than changing three clients.
Built expecting failure
Each integration assumes the other side will sometimes be slow, offline or returning bad data. Retries, idempotency and replayable queues come standard.
One owner per data field
We map which system is the source of truth for every field. Most sync bugs trace back to two systems both believing they own the customer address.
Docs developers will read
Interactive reference docs, working examples and a sandbox. Partners integrate faster and your team answers fewer emails.
Tools and platforms
- OpenAPI / Swagger
- GraphQL
- ASP.NET Core
- Node.js
- Azure API Management
- Azure Service Bus
- Azure Functions
- Azure Logic Apps
- AWS API Gateway
- Amazon SQS
- Postman
- OAuth 2.0 / OpenID Connect
Process
From first call to production
Discovery
A few working sessions to pin down goals, users, constraints and what "done" means. You get a written scope and estimate.
Design
Architecture, data model and clickable UI before heavy coding starts, so surprises show up early and cheaply.
Build
Two-week sprints with a demo at the end of each one. You see working software, not status reports.
Launch
Automated tests, staged rollout, monitoring and a rollback plan. Go-live should be boring.
Support
Bug fixes, updates and new features on a monthly plan, or a clean handover to your team.
FAQ
API Development & Integration: common questions
How much do API integration services cost?
A single integration between two systems with decent APIs typically costs $15k–$50k. Multi-system integration hubs and new public API platforms usually run $60k–$200k. Poorly documented legacy systems, heavily customized ERP fields and data cleanup are what push costs up.
Should our API use REST or GraphQL?
REST is the right default for most APIs, especially partner-facing ones, because it's simpler to cache, secure and document. GraphQL pays off when several front ends, such as web and mobile, each need different shapes of the same data. Some platforms use both: GraphQL for internal apps and REST for external partners.
Should we use an integration platform or custom code?
Low-volume, standard connections often fit well in Power Automate, Logic Apps or an iPaaS tool. Custom code makes sense when volumes are high, the logic is involved, or per-transaction pricing would get expensive. We compare both on three-year cost, not just the first invoice.
What happens when a third-party API changes?
We pin API versions where providers allow it and follow their change notices. Scheduled contract tests run against sandbox environments, so breaking changes show up in our alerts before they touch production data.
Can you integrate with our old on-premises system?
Usually, yes. If the system has no API, we can work through its database, file exports or a small on-premises agent that exposes a secure endpoint. It's slower than working with modern SaaS APIs, and we'll flag the risks during scoping.
How do you keep integrations secure?
Credentials live in a secrets vault, never in code. Every connection uses OAuth 2.0 or scoped keys over encrypted channels, with access logged for audit. Each integration only gets permission to the data it actually needs.
Related
Often paired with
Dynamics 365 Business Central
Cloud ERP rollouts and migrations from QuickBooks, Sage, NAV and GP, with AL extensions where you need them.
Learn morePower Platform
Power Apps, Power Automate, Power BI, Copilot Studio and Dataverse, with the governance to keep them maintainable.
Learn moreData Engineering
Pipelines, warehouses and lakehouses on Snowflake, Databricks or Fabric, modeled with dbt and monitored.
Learn moreIndustries we build for
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