I will build API integrations and webhooks


About this gig
Your app needs to talk to Stripe, a CRM, a shop or another system, and it needs to keep working when things go wrong.
I'm a senior backend engineer with over 10 years in healthcare, power and fintech, including payments. I build integrations in Python or C# that handle the messy parts most quick fixes skip.
What I build:
- One-way data pushes (e.g. new payments into a database or Google Sheets)
- Webhook receivers with signature checks
- Retries and idempotency, so no duplicate or lost records
- Two-way syncs between systems
- OAuth2 connections and nightly reconciliation jobs (Premium)
- Logging and failure alerts, so problems don't go unnoticed
Every order includes full source code, a README and setup notes. Premium adds a runbook and a recorded walkthrough.
Payments always use the provider's hosted checkout and test mode first. Card details never touch your server.
Please message me before ordering with the systems you want to connect and links to their API docs. Sandbox or test keys only, shared through Fiverr.
Not included: API subscription fees, front-end UI.
Get to know Andy M
Senior Software Engineer
- FromUnited Kingdom
- Member sinceNov 2026
- Avg. response time1 hour
Languages
English
FAQ
Do I own the code?
Yes. You get the full source code and all rights to it on completion. I don't reuse your code or data in other projects.
What do you need before I order?
A short description of what you need, example inputs and outputs, and links to any API docs. Message me first and I'll confirm the right package or send a custom offer.
My project is bigger than Premium. Can you still help?
Yes. Send me the details and I'll send a custom offer with a fixed price and timeline.
What if something doesn't work after delivery?
If my code doesn't meet the agreed spec, I fix it free. For later changes caused by third-party updates, add the 30 days of fixes extra.
How do you handle access and keys?
Test, sandbox or staging access only, shared through Fiverr. I never need production passwords or card details.
Where are you based?
The UK. I usually reply within one working day.
Which services can you integrate?
Any with a documented REST API or webhooks, such as Stripe, HubSpot, Shopify, Xero, Google Sheets and Slack. Send me the docs link to confirm.
Why not just use Zapier or Make?
This gig builds code you own, with no per-task fees and proper error handling. If a simple Zapier flow would do the job, I'll tell you.
Is payment integration secure?
Yes. I use the provider's hosted checkout, verify webhook signatures, and card data never touches your server.

