Istanbul Builds for a Market That Shops in Instalments
Split payments are ordinary here, not a promotion, and that single habit reshapes a commerce front end more than anything else in the brief. The instalment options a shopper sees depend on the issuing bank behind the card, on the product category, on campaign rules the acquirer publishes and on the merchant's own agreement. So the number of months, the total payable and any deferred start have to be calculated live, usually after a lookup on the first digits of the card, and presented on the product page as well as in the basket because shoppers compare on the monthly figure rather than the sticker price.
Behind that sits work nobody sees. Settlement arrives from the acquirer on its own schedule, commission differs per campaign, refunds unwind a plan rather than reversing a single charge, and the ledger has to reconcile all of it. Ask a web development company in Istanbul to describe a reconciliation problem it fixed in production and how the basket behaves when a shopper swaps cards at the last step. Teams who have shipped a real store here answer without hesitating; teams who integrated a payment button once will describe the button.
Distance Selling Rules Arrive as Pages, Not as Policy
Consumer legislation for online sales turns directly into interface work. A preliminary information form and a distance sales contract have to be presented before payment, the shopper has to actively confirm them, and the version they accepted has to be stored and retrievable later with its timestamp. Right of withdrawal, delivery timing, the seller's identity and the complaints route all need visible places in the flow rather than a link buried in the footer.
Two consequences follow for the build. First, those documents are dynamic, because they contain the order contents, so they are generated rather than static. Second, versioning matters: if you change the terms, existing orders must still resolve to the text that was accepted at the time. Suppliers who have been audited on this build it correctly the first time.
The Electronic Commerce Register Record Belongs in the Launch Plan
Online sellers are entered in the national electronic commerce register, and the resulting record is displayed on the site with the seller's identifying details. It is administrative work rather than engineering, but it has a launch-date dependency and it dictates a small set of pages and footer elements that need to exist before the store opens rather than after the first order.
Ask who handles the filing, because it is frequently assumed to belong to the other party and then nobody does it. A supplier that has taken clients through it will raise the subject before you do.
Electronic Invoices Belong to the Order Flow
Invoicing runs through the tax administration's electronic systems, with structured formats, digital signatures and approved integrator channels. For a store this means an invoice is issued as part of completing an order and delivered to the buyer digitally, which puts the integration inside your order module rather than inside your accountant's software. Plan the failure modes explicitly: the integrator is unreachable, a document fails validation, an order is cancelled after issuance and needs a corrective document.
Decide early whether the platform issues invoices itself through a provider or hands the job to an accounting system over an interface. Retrofitting this into a finished store is one of the more expensive reworks in the local market, and the heavier back-office side often sits better with software companies working next to the web team.
Turkish Text Has a Famous Way of Breaking Code
The dotted and dotless letter i is the canonical trap. A case conversion performed with the default locale turns a perfectly ordinary word into something that no longer matches, which silently breaks routing, search, tag comparison and any lookup that lowercases a string before comparing it. Every experienced local developer has debugged this at least once, and every foreign codebase brought here ships it at least once.
Around it sit the ordinary localisation questions: a stable transliteration rule for slugs that must never change afterwards, search that matches with and without accented characters because people type both, collation that sorts correctly rather than by byte order, and field lengths counted in characters rather than bytes so names are not truncated mid-word. Ask to see the slug rule in a candidate's existing project. It is a one-minute question that tells you how carefully they work.
Delivery Promises Depend on Carrier Integrations
Shoppers expect fast delivery, a tracking link and often a pickup point option, which means the courier is part of your data model. Shipment creation, label generation, status webhooks, cash collected on delivery where that is offered, and returns all flow between your platform and one or more carriers. Multi-carrier logic is common, because rates and coverage differ by region and merchants switch based on cost.
Ask which carrier interfaces a candidate has implemented and what their code does when a status webhook arrives twice or out of order. Duplicate handling is the difference between a clean order history and a support queue. Stores of any size usually benefit from adding ecommerce specialists to the team for this layer.
Consent, the Data Registry and Where Records Live
Personal data protection law here predates the build you are commissioning and is enforced. Consent has to be explicit and separable, marketing permission is not the same as service permission, commercial electronic messages run through a national permission management system, and data controllers of a certain size register with the supervisory authority. Transfers abroad have their own conditions, which matters the moment your analytics, email or support tooling sits on foreign infrastructure.
The practical artefact is a data map produced during the project: which form collects what, where each field is stored, which third-party script can read it, how long it is kept and how a deletion request is honoured. Ask for it as a deliverable. A supplier who cannot produce one is describing your risk, not managing it.
Hosting, Domains and the Accounts You Should Own
A local domain under the national registry expects documentation tied to a trade name or trademark, and the registrant on that record controls the name regardless of who paid for it. Open the registrar, hosting, analytics, payment and messaging accounts in your own organisation's name from the first day and let the supplier administer them under delegated access. This is the single most common cause of an ugly separation, and it costs nothing to avoid.
Hosting choice is genuinely open. Local providers deliver low latency to domestic visitors, international platforms bring better tooling, and an edge network in front of either usually settles the argument. Measure from a mobile connection in the market rather than from the supplier's office, and keep the same measurement as an acceptance criterion. The search side of the project depends on those same rendering and routing decisions, so scope it while the architecture is still open.
How to Compare Web Development Companies in Istanbul
Shortlist on artefacts. Open a live store a candidate maintains, put a product in the basket and watch the instalment table respond to different cards. Ask who filed their last client's register record. Ask how they version distance selling documents. Ask what their code does with a lowercased Turkish string. These questions take ten minutes and they sort the field.
Keep the trades separate so quotes describe the same project. Visual and interface craft belongs with design partners, a native release is a different cycle handled by mobile app developers, and engineering sits with the build team. Verified profiles, portfolios and client feedback for web development companies are collected on Edvido, and you can request proposals from your shortlist in one step.