Updated 2026-08-30. Written by Christopher Gilliland, founder of ZynVoss LLC — Fort Pierce, FL.
API in one sentence
An API lets two systems exchange data with rules—like a secure waiter between kitchens.
Webhooks vs polling
Webhooks push events when something happens. Polling asks “anything new?” on a timer. Webhooks are usually better when available.
What to give your developer
- Which system is source of truth
- Field mapping list
- Error behavior (retry? alert?)
- Test accounts
FAQ
Are API keys secret?
Yes. Treat them like passwords.
Next steps
APIs are how two offices stop lying to each other
If the website says a job is booked and the shop board does not, you do not have an “IT problem.” You have two sources of truth. An API is the rulebook between them: what can be read, what can be written, who is allowed, what happens when it fails.
ZynVoss LLC spends a lot of Fort Pierce hours on this unglamorous work. CRM, payments (Stripe), SMS, calendars, accounting exports. The code is not the hard part. The hard part is naming the source of truth and the field map before anyone writes a loop.
Webhooks vs polling, in shop language
A webhook is a knock on the door: “invoice 1042 just paid.” Polling is walking to the mailbox every five minutes. Use webhooks when the vendor offers them and you can verify signatures. Poll when the vendor is stuck in 2009 or you must not miss a window. Either way, log the payload, retry with a backoff, and alert a human after N failures. Silent failure is how you give away work.
What to hand a developer
- Which system owns the customer record.
- A column map: their field names, your field names, types, and “blank means what.”
- Error behavior: retry, ticket, or stop the sync.
- Test accounts that are not production. Sandboxes lie; still use them first.
- Rate limits and daily caps so you do not get banned at 8 a.m.
API keys are passwords. They do not go in email, chat, or a public GitHub. Rotate them when people leave. See CRM integration and integrations. If someone quotes “we will just Zapier it” for money movement or permissions, ask what happens when Zapier pauses on a weekend.
Failure is the real spec
Happy-path demos lie. Write what happens when the vendor returns 500, when the webhook is duplicate, when the customer is in the CRM twice. Retry with backoff. Alert a human after N failures. Do not silently skip an invoice-paid event or you will give away work. ZynVoss LLC logs payloads. You should too.
Test accounts that are not production. Sandboxes lie; still use them first. Rate limits: a morning burst of form spam should not ban you. Keys rotate when people leave. They do not go in chat. Custom vs Zapier: volume, money movement, and permissions. If the rule is “St. Lucie plus job type X assigns Y,” that is code. See CRM integration.