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I will review your rest API and openapi spec for a clean contract
Guillaume T
About this gig
Your API is a contract. Once clients build against it, breaking changes get expensive, so it's worth getting the design right before you ship v1.
I review your REST API design and OpenAPI spec and give you a clear, prioritized list of what to fix and why (resource modelling, naming, status codes, error formats, pagination, versioning and auth).
Good for teams shipping their first public or partner API, or anyone who inherited an API that "works" but feels inconsistent to build against.
What you get:
- A written review: issues ranked by impact, each with a concrete fix
- Resource & endpoint design checked against REST conventions
- Status codes, error shapes and pagination reviewed for consistency
- Auth and versioning assessed for safety and future-proofing
- Standard/Premium: a corrected OpenAPI spec your devs can build from directly
Works from an OpenAPI/Swagger file, a Postman collection, or endpoint examples; send me whatever you have. REST/OpenAPI focused; message me first for GraphQL or gRPC.
This is a design review and corrected contract. This is not an implementation. I'll sign an NDA before you share anything.
Get to know Guillaume T
Guillaume T
Engineering on demand from PCB schematics to API review
- FromBelgium
- Member sinceJun 2026
Languages
English, French, German, Korean, Dutch
Founder of Deepstack Engineering, specializing in the full hardware-software stack from silicon to API.
My background spans Battery Management Systems, nondestructive diagnostics, IC design, and power management, bridging electronics, embedded software, and material physics.
I deliver precise, documented work: SPICE simulation, PCB power integrity (PDN) analysis, REST API design review, register map documentation, and instrumentation data pipelines. Every deliverable is traceable and ready to hand to your team.
Need someone who understands both the hardware and software ends? Let's talk.
FAQ
I only have code or a Postman collection, not an OpenAPI file, is that OK?
Yes. I'll reverse the contract from your examples or endpoints. It adds a little turnaround, but you don't need a formal spec to start.
Do you implement the fixes or write the API?
No. This is a design review. You get a prioritized report plus, on Standard/Premium, a corrected OpenAPI spec your developers build from. Implementation is a separate engagement.
Do you review GraphQL or gRPC APIs?
This gig is focused on REST/OpenAPI. Message me first for GraphQL or gRPC. I'll tell you honestly whether I can help before you order.
How do you handle confidentiality?
I'll sign an NDA before you share your spec or code. Your API design isn't shared or reused.
How many endpoints does a package cover?
Basic suits a small-to-mid API; larger surfaces (many endpoints or multiple services) fit Standard/Premium or a custom offer. Tell me your endpoint count before ordering and I'll point you to the right tier.
