Cloud Solutions
SpaGreen Creative is a senior API development company that has built and integrated APIs for 8,200+ clients across 110+ countries — from Stripe-Salesforce syncs to GraphQL platforms powering 350+ products. We design REST and GraphQL APIs that are versioned, documented, rate-limited and observable, so your integrations stop breaking on Friday afternoons.
Our API development and integration services cover OpenAPI-first design, OAuth2 and JWT auth, webhook infrastructure, third-party connectors (Stripe, Shopify, HubSpot, Salesforce, Twilio, Slack), and full API platforms with developer portals. Whether you need a single Salesforce-HubSpot bridge or a public API powering thousands of partners, you get senior backend engineers — never juniors learning Postman on your dime.
Every engagement starts with a fixed-price API discovery, an OpenAPI 3.1 contract and a written integration plan. No black-box code, no per-endpoint surprises, no rate-limit disasters on launch day.
Common API problems we solve
Most API projects don't fail because of code — they fail because of contracts, retries and missing observability. Here's what teams typically arrive with and how we unblock them in the first 30 days:
- “Our Salesforce + HubSpot sync is broken — again.” We replace duct-tape Zapier flows with a typed integration service, dead-letter queues and a sync dashboard your ops team actually trusts.
- “We have 14 webhooks and no monitoring.” We move webhooks behind Hookdeck or Inngest, add retries, signature verification, replay and per-tenant alerting.
- “Third-party API rate limits killed our launch.” We add token-bucket throttling, exponential backoff, idempotency keys and per-vendor circuit breakers so one slow API can't take everything down.
- “REST or GraphQL? We picked wrong.” We migrate hot endpoints incrementally — REST for public, GraphQL for internal — without breaking existing clients.
- “No API versioning — every release breaks clients.” We introduce semver, deprecation headers, sunset policies and contract tests so you can ship without 3 a.m. Slack pings.
What you get with our API development services
Every API we ship is built on an OpenAPI-first, contract-driven workflow refined across hundreds of integrations. You get the discipline of a platform team with the speed of a sprint-based agency:
- OpenAPI 3.1 specs, code generation & contract tests
- REST & GraphQL APIs (Apollo, Pothos, Hasura, Mercurius)
- OAuth2, OIDC, JWT, API keys, SCIM & mTLS
- Webhook infrastructure: signing, retries, replay, dead-letter queues
- Third-party connectors: Stripe, Shopify, HubSpot, Salesforce, Twilio
- Rate limiting, idempotency keys & circuit breakers (Kong, Tyk)
- Developer portals, Postman collections & SDKs (TypeScript, Python, PHP)
- Observability: structured logs, tracing (OpenTelemetry), alerts
- API versioning, deprecation policies & backwards-compat tests
- Load testing with k6, Artillery & performance budgets
Our 4-step API engineering process
A predictable, contract-first process that turns vague integration briefs into shipped, monitored endpoints. Every sprint ends with a deployed API, an updated OpenAPI spec and a Postman collection you can hand to partners:
step 01
Discovery & API Design (Week 1–2)
Stakeholder workshops, data model design, OpenAPI 3.1 contract, auth strategy, versioning plan, rate-limit budget and a fixed-price proposal you can lock in.
step 02
Build & Document (Week 3–8)
Endpoints, webhook handlers, third-party connectors, SDKs and an auto-generated developer portal shipped behind feature flags with weekly demo builds.
step 03
Security & Load Test (Week 9–10)
OWASP API Top-10 audit, OAuth flow review, k6 load tests, chaos drills on third-party rate limits and a written security & performance report.
step 04
Publish & Monitor (Ongoing)
Public release, developer portal launch, OpenTelemetry tracing, latency & error-rate alerts, monthly reliability reviews and retainer-based maintenance.
APIs that don't break at 3 a.m.
Talk to a senior API engineer on WhatsApp. We'll scope your integration, public API or webhook platform within 24 hours.
- Integrations from $3,500
- API platforms from $11,000
- OpenAPI 3.1 contract first
- Reply in under 24 hours
Trusted by 8,200+ businesses · 110+ countries · NDA on request · Free quote in 24h
Tech stack we use for API engineering
We use a focused set of battle-tested tools so your API stays reliable years after launch:
- Backend: Node.js, NestJS, FastAPI, Laravel, Go, Django
- APIs: REST, GraphQL, Apollo Server, Hasura, gRPC, tRPC
- Gateways & rate limiting: Kong, Tyk, AWS API Gateway, Cloudflare
- Webhooks & queues: Hookdeck, Inngest, RabbitMQ, AWS SQS, Kafka
- Docs & testing: OpenAPI 3.1, Postman, Stoplight, k6, Pact
- Integrations: Stripe, Shopify, HubSpot, Salesforce, Twilio, Slack, Xero
Questions about API development & integration
Fixed-price integration projects (Stripe, HubSpot, Salesforce, Shopify, Xero) start at $3,500. Full custom API platforms with developer portals, SDKs and rate limiting start at $11,000. Dedicated API engineers are billed monthly from $4,200. You always receive a fixed-price proposal with itemised endpoints — never a per-hour blank check.
A single third-party integration (for example Stripe billing + webhooks) typically ships in 2 to 4 weeks. A full public API platform with versioning, SDKs and a developer portal takes 8 to 12 weeks. We lock the timeline in a 1–2 week discovery before any code is written.
REST exposes resources behind URLs and HTTP verbs — it's predictable, cacheable and ideal for public APIs and partner integrations. GraphQL exposes a single endpoint with a strongly typed schema, letting clients ask for exactly the fields they need — ideal for internal mobile/web clients with complex data needs. Many of our builds use both: REST for public, GraphQL for internal.
Yes. We ship public APIs with OpenAPI 3.1 specs, auto-generated developer portals (Stoplight, ReadMe or custom), typed SDKs in TypeScript, Python and PHP, Postman collections, sandbox keys and a written deprecation policy so partners can rely on you.
Yes — these are some of our most-requested integrations. We handle OAuth flows, webhook signing and replay, idempotency, rate-limit handling and bi-directional sync with dead-letter queues and a sync dashboard your ops team can monitor.
Every API is reviewed against the OWASP API Security Top 10. We implement OAuth2/OIDC, scoped API keys, mTLS where needed, rate limiting and abuse protection, signed webhooks, secrets management (AWS Secrets Manager / HashiCorp Vault) and full audit logging.
Yes. We move webhooks behind dedicated infrastructure (Hookdeck, Inngest or self-hosted queues) with signature verification, exponential-backoff retries, dead-letter queues, replay tooling and per-endpoint alerting so a flaky partner can't silently drop your data.
Yes. Every API ships with OpenTelemetry tracing, structured logging, latency and error-rate alerts (Datadog, Grafana or Sentry) and a 30-day bug-fix warranty. Retainer plans from $1,500/mo cover monitoring, vendor changes, new endpoints and partner support.
SaaS Development
Multi-tenant SaaS platforms where APIs are first-class — Stripe billing, RBAC, SSO and AI workflows.
Cloud Based Solutions
AWS, GCP and Azure architecture, API gateways and serverless infra that scales with your endpoints.
Business & ERP Solutions
Custom ERP, accounting and operations APIs that connect Salesforce, NetSuite, SAP and Xero cleanly.
AI Automation
LLM agents and event-driven workflows that consume your APIs and webhooks to automate operations.
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