VPS hosted middleware for reliable GoHighLevel and ServiceM8 integration

I am looking for an experienced developer to build and deploy a VPS hosted middleware service to run a reliable, production grade integration between GoHighLevel (GHL) and ServiceM8.

We are moving to a VPS hosted approach so we can run stable sync jobs, enforce correct data rules, improve logging and traceability, and reduce failures and timeouts.

This will be deployed into production for a real business, so quality, security, documentation, and maintainability matter.

Preferred hosting

DigitalOcean, Sydney region, Ubuntu LTS.

Scope and deliverables
1. Bi directional contact sync with deduplication

The middleware must reliably sync contacts between GoHighLevel and ServiceM8 in both directions.

It must prevent duplicates using sensible matching rules, including:
Email matching
Phone matching
Where needed, name plus address validation

It must be idempotent so reprocessing does not create duplicate records.

2. Multi site support (clients with multiple service addresses)

We have clients who may have multiple sites or service addresses. The solution must support multi site use cases, not just a single address per contact.

Your proposal must clearly define:
How multiple sites will be represented in GoHighLevel
How those sites map to ServiceM8
How new sites are created and linked to the correct existing client
How the system prevents a new site from creating a duplicate client profile

If the platform requires any manual association step for site records, that must be clearly documented and included in the handover.

3. Strict overwrite and data protection rules (critical)

There is a known risk of bad overwrites causing incorrect addresses, duplication, or broken client records.

The middleware must enforce strict rules such as:
Never overwrite a complete address with an incomplete address
Never overwrite a correct site address with a billing address or vice versa
Prefer the most complete and most recently verified data
Log every overwrite decision with before and after values

4. Reliable processing (webhooks plus scheduled sync jobs)

The system must support:
Webhook processing where available
Scheduled sync jobs and polling where needed
Safe retry behaviour with backoff and rate limit handling
A queue or retry strategy so failures can be reprocessed safely without duplicates

5. Logging, monitoring, and audit visibility (non negotiable)

The solution must provide:
Centralised logs showing what ran, what changed, and why
The ability to trace a single contact or site through the full sync path
Clear error reporting and notifications when failures occur
A simple way for us to access logs and status without being developers

6. ServiceM8 notifications handling (required)

We receive system generated ServiceM8 emails and notifications (job updates, scheduling changes, system alerts, etc). These must be captured reliably and logged into GoHighLevel in the correct way.

Requirements:
Log non replyable ServiceM8 system notifications as internal Notes or Activities in GoHighLevel, not Conversations
Log replyable client facing ServiceM8 emails in GoHighLevel as Conversations so admin can see and respond
Avoid duplicate logging if the same notification is reprocessed
Link each logged item to the correct Contact and where possible the correct site or job
Include clear tags or labels so staff can distinguish system notifications vs client communications

7. Gmail ingestion and parsing (required)

The middleware must ingest emails from Gmail and route them correctly into GoHighLevel based on rules.

Requirements:
Connect securely to our Gmail (preferred OAuth or secure delegated access, no plain text passwords)
Ingest inbound emails and identify whether they are client replies or enquiries (Conversation) or system notifications (Note or Activity)
Deduplicate processing so the same email is not imported twice
Maintain an audit trail including message ID, timestamp, sender, subject, and what record it was linked to
Provide basic configuration so rules can be adjusted over time (for example whitelists, sender domains, subject keywords)

8. Documentation and handover

Provide clear documentation covering:
How the VPS is set up and secured
How to deploy and redeploy
How to rotate API keys
How to view logs and health status
How to troubleshoot common issues
Full mapping and overwrite rules explained in plain English

Requirements and experience

You must have proven experience with most of the following:
GoHighLevel API
ServiceM8 API
Webhooks, scheduled jobs, and robust integration patterns
VPS deployment and basic DevOps
Logging, monitoring, and alerting

If you also have experience with Zapier, Make, or GoHighLevel workflows, include that in your proposal.

Security requirements

Firewall and SSH hardening
Secrets management approach (no keys stored in plain text)
Least privilege access where possible

Costs and ongoing costs (must be included)

Your proposal must clearly separate:

A One off setup cost (fixed price)

Includes server provisioning, middleware deployment, configuration, logging and monitoring setup, testing support, and documentation handover.

B Optional ongoing monthly maintenance

State exactly what is included, response expectations, and what is out of scope.

C Third party recurring costs

Provide estimates for:
DigitalOcean monthly hosting cost based on your recommended spec
Any other services you recommend (logging or monitoring tools), with monthly estimates

I will not accept proposals that only quote a build cost but do not state expected ongoing costs.

Acceptance testing (how success will be judged)

We will test your delivery using real scenarios, including:
Existing client books online and does not create a duplicate profile
A new site can be added under an existing client and remains correctly linked
Address fields do not overwrite incorrectly
Repeated sync runs do not create duplicates
ServiceM8 system notification email is logged as a Note or Activity and does not create a Conversation
Client reply email is ingested and appears as a Conversation linked to the correct Contact, without duplicates
Logs clearly show what happened for each test case

What to include in your proposal

Recommended tech stack and why
Recommended DigitalOcean server spec and monthly cost estimate
Timeline for an initial working version and then a production hardened version
Examples of similar work