How to Choose a Software Development Company in Istanbul

When you choose a software development company in Istanbul, or anywhere in Türkiye, the useful question is not "who is the best?" but "who can deliver this project in a way I can verify, and leave the code with me?" You can build a shortlist by checking four things: live work you can open and references you can call, access to the repository and source code from day one, a written process and contract, and defined support after launch. The checklist and scoring table below let you compare three or four candidates on the same criteria.

What should you check first when choosing a software development company?

Logo walls and generic success claims on agency websites do not help you compare anyone. Filter candidates in this order instead:

1. Scope fit: Has the company shipped something similar to your project (a web platform, a mobile app, an MVP, an integration) to production?
2. Verifiability: Is the work they show live today, and can you speak to the clients behind it?
3. Technical transparency: Where does the code live, who reviews it, and how does it reach production?
4. Commercial terms: Are the contract model, intellectual property, data protection and support terms written down?
5. Communication: Who will you actually talk to, how often, and in which language?

The order matters. Negotiating contract details with a company that has never built anything like your product wastes everyone's time.

How do you verify a portfolio and references?

A portfolio should be evidence, not a gallery of screenshots. For each case study, ask: is the product live today, what exactly did the company do (design, backend, everything), what problem was solved, and how was the result measured? If they say they built an app end to end, download it and use it. Slow screens, crashes or content that has not changed in months tell you more than the case study page.

The reference call is the most skipped and most informative step. Ask the company to connect you with a client whose project resembles yours, and ask that client:

• Did the project finish on the planned timeline and scope? If not, when and how did the company tell you?
• How were scope changes handled? Were there any invoices you did not expect?
• When a bug appeared after launch, how quickly did you get a response?
• Would you hire them again today?

Some work genuinely cannot be shown because of NDAs, and that is normal. But a company that cannot show any work and cannot arrange a single reference call deserves a much stricter technical review.

How do you assess technical depth without being an engineer?

Ask them to walk you through their process and listen for concrete answers. A mature team explains the following with tool names and examples rather than general reassurance.

• Repository access and code ownership: Does the code live in your own GitHub, GitLab or Bitbucket account from the first day, or will it be handed over as an archive at the end? The right answer is a repository where you can see the full commit history.
• Code review: Is every change reviewed by another developer before it is merged? The pull request history is the proof.
• CI/CD: Are tests, type checks and deployments automated, or does someone copy files to a server by hand?
• Tests: Which flows are protected by automated tests? Not every line needs one, but payments, login and permissions should.
• Environments: Is there a staging environment where you can see changes before they go live?
• Architecture decisions: Can they explain in writing why each technology was chosen? We cover the long-term effect of those decisions in our guide to scalable and maintainable software architecture.

Why does process transparency matter so much?

Most software projects do not fail for technical reasons; they fail because problems are noticed too late. A transparent process lets you see an issue within days instead of weeks. Look for:

• Short iterations: Is the work split into one or two week sprints, with something working shown at the end of each?
• Demos: Do you see progress as screens you can click in a test environment, rather than percentages on a slide?
• Reporting: Are completed work, effort spent and open risks shared regularly and in writing?
• Task tracking: Can you see the status of work yourself in a tool such as Jira, Linear or Trello?

A "we'll let you know when it's done" approach tends to produce large surprises in the final week, especially on fixed-price work.

Fixed price or time and material (T&M)?

Both models work when used in the right place. The problems start when a vague scope gets a fixed price, or when an open-ended T&M arrangement runs without controls.

A practical middle path: run discovery and scoping as a separate, fixed-fee phase, then continue development either at a fixed price on the now clear scope or as capped T&M. That reduces the risk of both models.

Who should own the source code and intellectual property?

You should own the source code, design files and documentation of software you pay for, and the contract should say so explicitly. Check:

• When IP rights transfer to you (with each payment or at the end of the project).
• Whether the vendor uses its own libraries or licensed components, and on what terms.
• That servers, databases, domains and app store accounts are opened in your name.
• That open-source components carry licences compatible with commercial use.
• What a handover looks like if you part ways: code, credentials, documentation and a handover note.

An app store account or domain registered in the vendor's name is one of the most common sources of friction when a relationship ends. Ask about it in the first meeting.

How do you evaluate data protection and security (KVKK)?

If your software processes personal data of people in Türkiye, the development company usually acts as a data processor, and obligations under Law No. 6698 on the Protection of Personal Data (KVKK) should be reflected in the contract. Official guidance is published by the Turkish Personal Data Protection Authority. If you also serve EU users, GDPR applies alongside it. Ask the vendor:

• Who will access live user data, and with what permissions? Will real data be used in development or test environments?
• Are passwords, API keys and other secrets kept out of the repository and stored securely?
• Which provider and which country will host the data? Is there a cross-border transfer?
• How are authorisation, logging and backups designed, and what happens after a security incident?
• Are confidentiality and data processing clauses included in the contract?

What should post-launch support and the SLA cover?

Software is not finished on launch day. In the first weeks real users find bugs that never appeared in testing. The proposal should answer:

• How long is included post-launch support, and what does it cover (bug fixes, small changes)?
• What is the response time (SLA) for a critical bug, and who can you reach outside office hours?
• What does a maintenance agreement include: dependency updates, security patches, server monitoring?
• For mobile apps, who is responsible for compatibility with new iOS and Android versions? We explain why distribution is the hard part on our mobile application development page.

How do you test team continuity and communication?

The person who sells the project is often not the person who builds it. Ask for the names and roles of the people who will work on your project, and meet the technical lead early if you can. When someone leaves the team, knowledge survives only through documentation, code review and written decisions; a project that lives in one developer's head is a risk.

On communication, agree up front on the meeting rhythm, the shared channel (Slack, Teams or email), how quickly questions get answered and the language of documentation. For international clients working with a team in Türkiye, confirm that the people you will talk to day to day, not only the sales contact, work comfortably in your language.

Which red flags should stop you?

• A price far below the other proposals: The gap is usually closed by cutting tests, code review, documentation or support, and you pay for it later.
• No written scope: "We'll build what we discussed" leaves you with nothing in a dispute.
• No repository access: If you cannot see the code until the end, you do not know what is being written.
• "Everything ready in two weeks": A firm deadline given before the requirements are heard is a sales line, not an estimate.
• "Yes" to every question: A good team pushes back, suggests a smaller scope and sometimes says "you don't need this yet".
• Infrastructure in the vendor's name: Servers, domains or store accounts are not opened in your name.
• Single-person dependency: All knowledge sits with one developer and nothing is written down.

A scoring table for comparing software development companies

Score each candidate from 1 to 5 on each criterion, multiply by the weight and add up. Adjust the weights to your project; the ones below are a reasonable starting point for most web and mobile work.

Take a second look at any candidate that scores 1 on a single row, even with a high total. Code ownership and written scope in particular are hard to fix later.

What should you ask in the first meeting?

1. Can you show us live work similar to ours, and can we talk to that client?
2. Who will work on the project, and who is the technical lead?
3. Which repository will hold the code, and when does our access start?
4. How does a change reach production, and which steps are automated?
5. How often, and in what form, will we see progress?
6. If scope changes, how is the impact on time and budget calculated?
7. What support is included after launch, and how does maintenance work after that?
8. Where do you see the biggest risk in this project?

The last question is especially revealing: a team that can name a concrete risk has actually thought about your project.

What are the practical advantages of an Istanbul-based team?

Location is not a quality criterion on its own, but it makes some things easier:

• Time zone: Istanbul is on UTC+3 all year, which overlaps well with European working hours and the Gulf, so questions get answered the same working day.
• Face-to-face workshops: For companies in Türkiye, one or two discovery sessions at the same table can replace weeks of email.
• Turkish contracts and invoicing: For Turkish companies, the contract is drafted in Turkish under Turkish law and invoices follow local rules, with no cross-border payment or currency handling.
• KVKK familiarity: Local teams deal with KVKK obligations, e-invoicing and local payment integrations as part of their everyday work.

A team in another city or country can also deliver well with the right process. What decides it is the criteria in this article, not the address.

How does Detartech answer these criteria?

We build web, mobile and MVP projects from our office in Ümraniye, Istanbul. Our own answers to the checklist above:

• We work in two-week sprints and show a working build at the end of each one.
• Every change is reviewed by another developer before it is merged, and tests and deployments run through an automated CI/CD pipeline.
• The repository sits in your own account with its full history, and servers, databases and domains are set up on accounts opened in your name. The delivery package is described on our web development page.
• 30 days of post-launch support are included in delivery.
• On MVP development projects we hand over technical debt in a written note.

You can review live work on our success stories page; Lextum AI (AI-assisted legal document management) and Welldone (industrial laundry management) are examples of how we work.

If you would like to go through this checklist against your own project, the first consultation is free and we reply within 24 hours. A short summary in our quick quote form is enough to start.

Frequently Asked Questions

Which is the best software development company in Istanbul?

There is no single "best" company for everyone; the right one depends on your project type, budget and in-house team. Instead of relying on ranked lists, score three or four candidates with the table in this article, call their references and compare repository access, written scope and support terms side by side.

What must a contract with a software company include?

Written scope and acceptance criteria, a payment schedule, transfer of source code and IP to you, ownership of infrastructure accounts, confidentiality and data protection clauses, and post-launch support with response times. Also put in writing how a handover works if you part ways.

How can I judge a software company's skills without a technical background?

Ask for repository access, ask them to show pull request and code review history, and have them explain step by step how a change reaches production. Concrete answers with tool names and examples are a good sign. If needed, have an independent technical advisor review the proposal and the code.

Is a fixed-price project safer than T&M?

If the scope is clear and stable, a fixed price gives you budget predictability. If the product will be shaped by what you learn from users, T&M is more flexible but needs sprint reports and a budget cap. Keeping discovery as a separate phase reduces the risk of both.

Can a foreign company work with a software developer in Türkiye?

Yes. Contracts can be drafted in English, invoicing can be done for foreign clients, and daily work runs remotely with occasional in-person workshops. Check the same criteria as with any vendor, and clarify the governing law, data hosting location and communication language in the contract.

What happens if I want to switch software companies?

If the code is in your repository, the infrastructure is in your accounts and documentation is current, switching is a manageable job. If those sit with the vendor, the switch starts with recovering access and takes much longer. That is why the handover clause belongs early in the contract discussion.