API integration services that reach production
Connect CRMs, payments, operational tools, partner platforms or internal applications with agreed data mapping, failure handling, testing, monitoring and documentation.
API integrations · workflow automation · software rescue
Software shipped. Without the agency layers.
I help growing companies connect systems, automate manual work, rescue stalled projects and build custom software. Before work starts, you know the price, what will be delivered and how we will test it.
10+ yearsBuilding production software
5 years at ViatorSupplier connectivity at marketplace scale
Scale-up experienceSystems supporting high-traffic products
Work directly with meSame engineer from first call to release
What I can deliver
Choose the problem you need solved.
Before work starts, you receive a written proposal covering what will be delivered, what depends on your team or third parties, how we will test it and the fixed price.
Integrate and automate
Business process and workflow automation
Replace one repetitive export, copy-paste process or fragile handoff with a workflow your team can run, monitor and troubleshoot.
Stabilize and continue
Software project rescue and stabilization
Find out why a project is stalled or unreliable, agree on the recovery plan, fix the approved work, test it and release it.
Application maintenance and connected improvements
Keep an existing application reliable and ship related improvements without rebuilding context every time work resumes.
Selected work
Evidence from systems built for real operations.
Product ownership, integrations and technical foundations across construction, events and restaurant operations.
01
Construction technology · Canada
Build Link ID
Facial recognition foundation for workforce clock-ins
Technical leadership, system foundations and AWS Rekognition integrations for a construction workforce product that is now running in production.
- Technical lead
- AWS Rekognition
- Production
02
SaaS product · Brazil
Plannifier
An event-operations product built beyond MVP
A live product covering guests, budgets, suppliers, timelines, client collaboration and AI-assisted document imports.
- Product ownership
- Full-stack
- Live SaaS
03
API integration · Restaurant operations
DOM Burguer
Order data turned into weekly operational reporting
A serverless GloriaFood integration, reporting dashboard and customer feedback flow used for several years at approximately 300 orders per week.
- Full-stack engineer
- AWS serverless
- Used for years
Delivery partnership
Senior ownership with additional capacity when the project needs it.
Cavendish and Web Star Studio combine technical leadership, design and implementation capacity according to each project's needs. Roles and responsibilities are agreed before delivery begins.
Why work with me
The engineer you speak with is responsible for delivery.
I take on software work that needs senior judgment but not a large agency team. I define the approach, write or review the code, coordinate any approved specialists and stay responsible through testing and release.
During five years at Viator, a Tripadvisor company, I worked on supplier connectivity and marketplace systems supporting high-traffic products. I also worked on technical SEO infrastructure used across millions of pages. The work involved legacy systems, external partners, multiple teams and production releases where reliability mattered.
- 01
One responsible engineer
You are not passed from sales to an unknown delivery team. I remain your technical contact from the first conversation through release.
- 02
Extra specialists only when needed
If the project needs another skill, the proposal names the person or role, their access and what they will deliver. Nothing is handed off without your approval.
- 03
Your code and documentation
You own the agreed code and project documentation. Ongoing work is optional, not a condition of receiving a usable handover.
Ways to work
Start with a project, not a long-term commitment.
If the work is clear enough to estimate, I send a fixed-price sprint proposal. If important technical questions remain, Technical Discovery answers them first. Ongoing support is available after I understand the system.
Before work starts
You know what will be delivered and how it will be tested.
The proposal states the deliverable, exclusions, access required, third-party dependencies, schedule, test scenarios and support included after release.
- Commercial model
- Fixed price
- Definition of done
- Agreed in writing
What the work can include
- Understand: the problem, business impact, systems and people involved
- Define: the deliverable, exclusions, access and test scenarios
- Design: a practical solution for the agreed work
- Build: configure, develop, integrate and test
- Review: run the agreed tests with your team
- Release: deploy and fix defects covered by the proposal
- Document: explain operation, ownership and known limits
If my implementation needs more work to pass the agreed tests, I fix it at no extra cost. New requirements, missing client inputs or unexpected third-party limitations may change the price or schedule, but only after written agreement.
Pick the right starting point.
A 20-minute conversation is usually enough to decide whether the next step is a sprint, Technical Discovery or a different provider.
Integration & Automation Sprint
For an API integration, workflow automation, rescue or other clearly defined software delivery.
- Fixed price
- From US$4,000
Most sprints take 2 to 4 weeks when the systems, access and requirements are understood. The written proposal sets the exact deliverable, schedule and test scenarios.
- One clearly described software deliverable
- Scope, exclusions and dependencies agreed before work starts
- Implementation, testing, release and documentation
- Post-release defect support stated in the proposal
Technical Discovery
For important work that cannot yet be estimated with confidence.
- Fixed price
- From US$1,500
Use it when legacy code, undocumented APIs, data, permissions or vendor behavior must be investigated before implementation can be priced or scheduled.
- Map of the current system and workflow
- Options, risks and external dependencies
- Proposed test and acceptance scenarios
- Implementation recommendation you can use with any provider
Ongoing Engineering Support
For software I already understand that needs regular maintenance and related improvements.
- Monthly service
- From US$2,500/month
Available after a project or Technical Discovery when keeping context is more efficient than starting a new engagement for every change.
- Written monthly scope and priorities
- One active priority or group of related changes
- Agreed maintenance, monitoring and improvements
- Scheduled engineering work, not 24/7 or on-call support
About
João Paulo Cavendish
I am a software engineer with more than 10 years of experience. I started in California agencies, built high-stakes systems for banking and the public sector in Luxembourg, and spent five years working on supplier connectivity and marketplace systems supporting high-traffic products. I also worked on technical SEO infrastructure used across millions of pages.
Today I run Cavendish and work directly with growing companies on integrations, automation, software rescue and custom software. I lead each project from scoping through release and bring in specialist help only when it improves the work and the client approves it.
- Working model
- Remote · founder-led delivery · US-friendly overlap
- Capabilities
- APIs · supplier connectivity · integrations · automation · full-stack software
- Languages
- English · Portuguese · French
- Experience
- 10+ years building agency, banking, public-sector and marketplace software
Frequently asked questions
What to expect before we work together.
What is an Integration & Automation Sprint?
It is a fixed-price project for one clearly described software deliverable. Before implementation, the proposal states what is included, what is not, the access and dependencies required, the schedule, the test scenarios and the support included after release. Most sprints take 2 to 4 weeks when the system is sufficiently understood.
Which services can a sprint cover?
Common projects include API integrations, workflow automation, software rescue, internal tools and focused improvements to an existing application. The proposal describes exactly what I will deliver for your project.
What does “from US$4,000” mean?
US$4,000 is the starting price for a sprint. The final price depends on the deliverable, systems involved, technical risk, dependencies and schedule. Taxes and third-party costs are listed separately when they apply.
When is Technical Discovery needed?
Discovery is useful when legacy code, undocumented APIs, data quality, permissions or vendor behavior must be investigated before implementation can be priced. Starting at US$1,500, it provides a system and workflow map, options, risks, dependencies, proposed test scenarios and an implementation recommendation you can use with Cavendish or another provider.
How do we agree that the work is complete?
We write the test scenarios before implementation. Depending on the project, they may cover data mapping, timing, duplicate prevention, failure records, alerts, automated tests, deployment evidence and review by your team. Revenue and third-party approval are not used as software acceptance tests.
What happens if the work takes longer?
If my implementation needs more work to pass the agreed tests, I fix it at no extra cost. New requirements, an added system, delayed client input or an unexpected platform limitation may change the price or schedule. Any change is explained and agreed in writing first.
Who performs the work?
João leads the project and remains your technical contact from scoping through release. If another specialist is needed, the proposal identifies their role, access and deliverable. No work is handed off without your approval, and approved specialists work under suitable confidentiality and intellectual-property terms.
Is ongoing support available after delivery?
Yes. Ongoing Engineering Support starts at US$2,500/month for software I already understand. The monthly scope may include maintenance, monitoring and related improvements. It is scheduled engineering work, not unlimited tasks, 24/7 support or on-call incident response.
Do you guarantee revenue or savings?
No. I commit to the software deliverable and the agreed tests. Revenue, savings and operational impact also depend on demand, adoption, business decisions and third parties. We can measure those results without pretending that software alone controls them.
What access will you need?
It depends on the project and may include source code, documentation, analytics, test environments and relevant business tools. I request only the access needed for the work. Never send passwords through ordinary email or chat.
What are you trying to ship or fix?
Share the problem, the systems involved and any deadline that matters. I will reply with questions or suggest a 20-minute call to decide whether I can help.
Integration & Automation Sprints start at US$4,000. Technical Discovery starts at US$1,500 when the system needs investigation before implementation can be priced.