You will get Make Your Create/Callback Endpoint Idempotent + HMAC-Signed (Go/Python)
Project details
I make create / callback endpoints safe under retries — and the outbound calls they trigger safe against replay. One endpoint becomes safe under retries — same key returns the same result, never a duplicate. Outbound calls signed (HMAC-SHA256), polling replaced with WebSocket push (optional). Ships with tests.
Web Programming Project
API DevelopmentProgramming Languages
Python, GoCoding Expertise
Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$349
|
Standard
$849
|
Advanced
$1,899
|
|---|---|---|---|
| Delivery Time | 5 days | 10 days | 21 days |
Number of Revisions | 1 | 2 | Unlimited |
Source Code |
Frequently asked questions
About Roman
Backend Engineer | Python & Go | Devops
Yerevan, Armenia - 3:45 pm local time
I specialize in building reliable web applications, CRM systems, and e-commerce solutions using Django (PostgreSQL, Redis, Celery, Django REST Framework) as well as developing high-performance REST APIs with Go (Gin) following clean architecture principles.
Over the last 5 years I have:
• Worked as Chief Developer leading a small development team
• Successfully delivered multiple projects as a freelancer
• Refactored and modernized legacy codebases
• Designed secure system architectures and configured CI/CD pipelines
I continue to provide long-term support for several clients.
I’m focused on writing clean, secure, and maintainable code that brings real value to businesses.
Steps for completing your project
After purchasing the project, send requirements so Roman can start the project.
Delivery time starts when Roman receives requirements from you.
Roman works on your project following the steps below.
Revisions may occur after the delivery date.
Kickoff chat (free, 15–30 min)
Idempotency-key source (`Idempotency-Key` header vs external_id in body), store (Redis SET NX EX vs Postgres `ON CONFLICT`), TTL window, and — for Standard/Premium — the signing scheme and reconnect window. No code starts until this is agreed.
You send the slice
The endpoint's source file plus surrounding context (router config, DB schema for the affected table, the third-party SDK call if any). Full repo, a zipped subdirectory, or collaborator access — whatever your NDA allows.