How to Hire a Software Developer in Thailand 2026: From Requirements to Handover

A story we hear often from business owners who have hired a software developer: a few conversations, a deal agreed over chat, and the developer goes off to build. Months later the system isn’t what they had in mind, and every change request is “out of scope”. In the worst cases the developer disappears with the source code, leaving a system nobody else can touch.

Most of these problems have nothing to do with coding skill. They come from a fuzzy start: no requirements document, no milestones, no agreement on testing and no conversation about support after handover.

This guide is for business owners about to hire a developer or commission custom software, whether from a freelancer, a small team or a software house. We’ll go from before you start, through development, to after handover. If you’re not yet sure whether to build or buy, read custom software vs SaaS first.

Before You Hire, Get Clear on These Questions

Before contacting any developer, try to answer these. The clearer your answers, the more accurate the conversations and estimates will be.

What problem are you solving? For example: stock never matches, sales can’t be tracked, or booking chats have become unmanageable.
Who will use the system? How many staff, how many roles, and will outside customers use it?
How is this work done today? Excel, paper or another program?
How will you measure success? Less time on paperwork, fewer errors, real-time numbers?
Is there already off-the-shelf software that solves this? If it fits well enough, you may not need to build anything.
What does it need to connect to? Accounting software, payment channels, LINE OA?

If you can’t yet picture what such systems look like, browse our web application examples for business.

Write a Requirements Document Others Can Understand

A requirements document protects both the client and the developer. It doesn’t need to be a thick technical spec, but both sides must read it the same way. Sections to include:

Overview and goals: what the system is for and which problem it solves.
Users and permissions: what each role can do, e.g. sales create quotations, managers approve discounts.
Workflow: the process step by step from start to finish.
Feature list: split into “must have” and “later”.
Real sample documents and data: the quotation you use now, a sample Excel file.
Integrations: which systems, and what data goes back and forth.
Other requirements: mobile use, English language support, rough number of concurrent users.

A technique that helps a lot is writing user stories, for example: “As an admin, I want to see every open technician job on one page so I can follow up by phone straight away.” This tells the developer the reason behind a feature, not just which buttons to add.

A good developer will help refine this document, ask questions you hadn’t thought of and point out contradictions. If a developer agrees to everything without asking a single question, treat that as a warning sign.

The Software Development Process Clients Should Know

Whoever you hire, good software projects tend to follow similar stages. Knowing them tells you when your input is needed.

Stage	What happens	What the client does	Expected output
1. Requirements	Interview users, observe the real workflow	Make time to talk, share sample documents	Requirements document
2. Design	Screen designs, data structure	Review wireframes or prototypes	Approved screen designs
3. Development	Build module by module	Attend demos, give feedback quickly	Testable modules
4. Testing	Developer tests, then users test	Test real scenarios, report issues	List of fixed issues
5. Data migration and training	Import old data, train users	Clean the data, schedule training	A team that can actually use it
6. Go-live	Launch on real data, monitor closely	Set the cut-over date from the old system	System running on live data
7. Post-handover support	Bug fixes, updates, further development	Report issues properly, plan the next phase	A stable system that keeps growing

The stages clients most often skip are 2 and 4, which are exactly the ones that prevent misunderstandings. Seeing sample screens before real code is written saves a great deal of rework.

Phases and Milestones Reduce Risk on Both Sides

A project agreed as one lump, delivered once at the end, is high-risk, because by the time you discover it’s not what you wanted, it’s too late. Splitting it into phases and milestones works better.

How to split it:

Phase one (MVP): only the features that solve the core problem, live as quickly as possible.
Later phases: add features based on feedback from real use.
Milestones within each phase: for example screen design, core module, then testing and launch.

Each milestone should have a tangible deliverable, such as clickable screens or a module that has passed testing, not “50 percent done”, which nobody can verify. Paying per milestone tied to real deliverables keeps both sides comfortable.

Also agree up front on change requests. Requirements changing along the way is normal, but there should be a clear process for how changes are requested, how their impact on the timeline is assessed and who approves them.

Source Code and Data Ownership

This is the issue clients most often forget to raise, and it causes the most serious problems later. Get it agreed in writing:

Who owns the source code? After full payment, do you get full rights to all the code, or only a licence to use it?
Where does the code live? It should be in a version control system (such as Git) that you can access, not only on one developer’s laptop.
Third-party components: systems usually rely on external libraries or services. Know which ones, and their terms of use.
Hosting, domain and cloud accounts should be opened in your business’s name, with the developer given access, not the other way round.
The data belongs to you and can be exported whenever you need it.
Documentation: installation steps, system structure and key credentials, delivered in writing.

The simple test: if the original developer can’t continue one day, a new developer should be able to take over without starting from scratch.

Testing and Acceptance

Good acceptance isn’t “I clicked around and it seems fine”. It needs criteria agreed in advance.

Write Acceptance Criteria Along with the Requirements

Every feature should have a condition that defines a pass. For example: “When a quotation has a discount above the limit, it must go to a manager for approval, and sales cannot send it to the customer until it’s approved.”

Test with Real Scenarios

Have the staff who will actually use it do the testing, with data close to the real thing, and try unusual cases too: incomplete forms, cancelling halfway, using it on a phone with a slow connection.

Log Issues Systematically

Report each issue with the steps taken, the expected result, the actual result and a screenshot. A chat message saying “the system doesn’t work” makes fixes very slow.

Agree on a Warranty Period

Agree that after handover the developer will fix bugs caused by their own work for a set period, and draw a clear line between a “bug” and a “new feature”.

Comparing Your Options

Option	Strengths	Watch out for	Best for
Solo freelancer	Direct communication, flexible	If they fall ill or overbook, everything stops	Small systems with clear scope
Freelance team	Several skills (design, coding, testing), still flexible	Check who holds overall responsibility	Small to mid-sized systems that keep evolving
Software house	Formal process, large team	More process, slower to adapt	Large systems, organisations needing full documentation
In-house team	Full control, deep business knowledge	You must recruit and manage people yourself	Businesses where software is the core

No option is best for everyone. What matters is a clear process and clear agreements.

Warning signs when talking to a developer:

They quote a price and timeline immediately without asking for details.
They have no portfolio, or can’t explain past work.
They never mention testing, source code handover or post-launch support.
They ask for full payment before starting.
Communication is difficult and replies are very slow even during the sales stage.

Support After Handover and Further Development

Software is never “done”. Live systems need ongoing care, because browsers, operating systems, libraries and connected services change constantly.

What to agree on for support:

Backups: automatic or not, where they’re stored, and whether a restore has actually been tested.
Security updates: who is responsible and how often.
Monitoring: if the system goes down, who finds out first and who do you call? (See what to do when your website is down.)
Issue reporting channels and response times.
New features: billed as new work, or included in a support package?

An unmaintained system slowly degrades until one day it stops working at the moment the business needs it most, such as the high season for tourism businesses in Southern Thailand.

How Our Freelance Team Works

Southern Whale is a freelance team developing websites and systems for businesses in Southern Thailand. We start by helping you write clear requirements, split the work into phases and milestones you can verify, show you sample screens before building, hand over source code with documentation, and plan ongoing support after launch. See our software development service, or if you already have a project in mind, tell us about it on LINE OA. Even if it’s just an idea, we can help you figure out where to start.

FAQ on Hiring a Software Developer

Do I need IT knowledge to hire a developer?

No. What you need to know best is your business and its workflows. Explaining the technical side in plain language is the developer’s job.

Can I start without a requirements document?

Yes, but have the developer gather requirements and write the document as the first piece of work, before any coding. Many developers treat this as a separate first milestone.

What determines the cost of custom software?

The number of screens and features, the number of user roles, the complexity of the business rules, the number of integrations, any data migration and the level of post-launch support. A clear requirements document makes estimates much more accurate.

When should I ask for the source code?

Agree on it before work starts. Ideally, the code lives in a repository you can access throughout the project, rather than being handed over at the end.

What if the original developer stops working on it?

If you have the source code, documentation and access to hosting, a new developer can study it and take over. Without them, parts or all of the system may need rebuilding, which is why this needs to be agreed from the start.

How long does custom software take to build?

It depends on scope. A small, well-defined system doesn’t take long; one with many modules takes longer. Working in phases lets the business start using version one early and add the rest while it’s in real use.