01 · REST APIs
Resource-oriented and predictable.
Standard HTTP semantics, consistent error responses, OpenAPI 3.x documentation auto-generated from code. Versioning strategy that does not break clients.
Service · APIs
Custom API development services.
Secure, scalable, high-performance APIs for smooth communication between applications. RESTful, GraphQL, and third-party API integration designed to scale. Strongly typed contracts, OpenAPI documentation, and integration with the third-party services your platform depends on.
Our expertise
API design through production support.
We design APIs your developers will not hate. Thoughtful resource modeling, consistent conventions, predictable error responses, and documentation that stays in sync with the actual implementation.
02 · GraphQL
Single-endpoint, type-safe, client-driven.
When the front-end needs flexibility and round-trip count matters. Apollo Server, schema federation, persisted queries for production efficiency.
03 · Third-party integrations
Stripe, HubSpot, Salesforce, custom partners.
Most APIs you write live in a graph of other APIs. We handle the integration layer, retries, idempotency, and webhook management as part of the build.
04 · API gateways & rate limiting
AWS API Gateway, Kong, custom edge logic.
Production APIs need rate limiting, abuse detection, geographic routing, and observability at the edge. Built into the architecture, not added later.
Capabilities
Backend and integration capabilities.
API engineering is a slice of broader backend work. We bring full-stack capability into every API engagement: data modeling, queue design, observability, and security.
Authentication & authorization
OAuth 2, OIDC, JWT, mTLS, API keys.
Authentication patterns that scale and are auditable. Authorization models (RBAC, ABAC) that match your business logic, not just role-based hierarchy.
Webhooks & event delivery
Reliable, retryable, signed.
Webhooks done right: signed payloads, retry-with-backoff, idempotent delivery, dead-letter queues. The patterns that prevent silent data loss.
Real-time & streaming
WebSockets, Server-Sent Events, long-polling.
When pull-based REST does not fit. Live dashboards, collaborative editing, real-time notifications. Patterns that survive flaky networks.
Documentation & SDKs
OpenAPI, Postman collections, generated SDKs.
API documentation that stays current. Generated client SDKs for major languages. Postman collections kept in lockstep with the deployed API.
How we work
Four phases. Same team across all four.
The phases that apply to every engagement, not just api development. The team that scopes does the building, and the operating.
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Phase 01 · 2–4 weeks
Discovery and scope.
Stakeholder interviews, technical review of existing systems, risk register, written scope with milestones and exit criteria.
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Phase 02 · 3–12 months
Build and iterate.
Two-week sprints with working demos. Senior leads on every sprint review. Code reviewed, accessibility checked.
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Phase 03 · 2–6 weeks
Cutover and stabilization.
Parallel run with rollback path. On-call coverage during the launch window. Stabilization continues until incident rate trends to zero.
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Phase 04 · ongoing
Operate and evolve.
Multi-year retainer with the same team that built the product. Monthly check-ins, quarterly business reviews.
Read the full engagement model on the How We Work page.
Industries we serve
API Development across 15 verticals.
Six core verticals where OST has the deepest engagement experience. Plus nine adjacent industries served on selective engagements.
01
Education
K-12 charter networks, higher education, public sector portals.
02
Nonprofit & Civic
Donor-cycle nonprofits, advocacy organizations, civic platforms.
03
Healthcare & Wellness
HIPAA-aware platforms, medical directories, telemedicine adjacency.
04
Real Estate Technology
Multi-tenant SaaS, brokerage tools, self-storage operators.
05
E-commerce & Marketplaces
OpenCart specialists, custom commerce, $10B+ in transactions processed.
06
Manufacturing & B2B
Industrial platforms, B2B safety-tech, embedded engineering teams.
Also serves on selective engagements
Frequently asked questions
Common questions on api development engagements.
REST or GraphQL — which is right for me?
REST when the client needs are predictable and the resource model fits HTTP semantics. GraphQL when the front-end needs flexibility, round-trip count matters, or you have many client variants. Both can coexist behind the same gateway.
How do you handle versioning?
URL versioning (/v1, /v2) for major breaking changes. Header-based versioning for internal APIs. We design backward-compatible changes when possible to avoid forced client migrations.
What about API documentation?
OpenAPI 3.x specifications generated from code, hosted on a developer portal. Postman collections kept in sync. Working examples for every endpoint. Changelog and deprecation timelines documented.
Can you integrate with our existing systems?
Yes. Most API engagements include integration with CRM, ERP, payment, email, and SSO systems already running in your stack. We map the integration surface as part of discovery.
What about API security?
OAuth 2 / OIDC for authentication. Rate limiting and abuse detection at the edge. Input validation, output encoding, CSRF and CORS handled correctly. Annual penetration testing on production APIs.
Ready to build?
Pick a path forward.
Multiple ways to start: schedule a discovery call, run our cost calculator for a budget bracket, or use the contact form for a written response.