Chatbot development pricing 2026: website, Zalo OA and Facebook

Ask three vendors to build the same chatbot and you can easily get three numbers that differ severalfold, with none of them explaining why. This article breaks a chatbot development quote into its parts, shows where the price shifts by channel, and lists the costs that always appear but rarely make the first page.

What does a 2026 chatbot development quote actually cover?

A complete quote always has three blocks of money, not one number: a one-off setup fee to build the conversation flows and load your data, a monthly running fee covering the AI model plus hosting, and a platform fee if the bot lives on Zalo OA or a SaaS tool. The table below shows reference ranges as of September 2026 for small and mid-size businesses in Vietnam. The exact figure moves with the number of channels, the number of integrations, and how clean your existing data is.

Level	What it does	Setup fee	Monthly running fee
Scripted chatbot on an existing platform	Button-driven flows: menu, price list, opening hours, repeat questions	5 - 15 million VND	A few hundred thousand VND in platform fees
Subscription AI chatbot SaaS	Understands free-form questions, but hard to load deeply with your data and voice	Close to zero	A few hundred thousand to a few million VND
Custom-built AI agent	Knows your products, speaks your brand voice, connects CRM, orders and bookings	From tens of millions of VND	Model plus operations, scales with volume

For a published price list to compare against: FChat lists its scripted chatbot build service in two packages, BASIC at 2,000,000 VND to set up one flow with content supplied by the customer, and ADVANCED at 10,000,000 VND including flow consulting, copywriting and CRM integration. Both are one-off and explicitly exclude 10% VAT and software fees (checked 14 September 2026). In other words, the headline number on a quote is build work only; the monthly platform fee is a separate line. That line is public too: FChat's CHATBOT plan is 299,000 VND a month and its BUSINESS plan with API and CRM is 999,000 VND a month, VAT included; AhaChat Pro is 700,000 VND for one month or 5,000,000 VND for a year, about 415,000 VND a month. Subscription prices change often, so many roundup articles online no longer match the current price pages.

Why does the same bot cost differently on a website, Zalo OA and a Facebook Page?

The intelligence layer is the same, but each channel has its own technical constraints, so the workload differs. This is why a single quote lumping all three channels together is usually inaccurate.

• Website: no platform fee, but you have to handle anonymous visitors, keep context within a session, and fit the widget into an existing design. Usually the cheapest place to start.
• Zalo OA: add 1 - 6 million VND a year depending on plan, plus roughly 55 VND for every message sent outside the 48-hour window. In exchange, this is where Vietnamese customers actually message. Plan-by-plan detail is in our guide to Zalo OA chatbots for business.
• Facebook Page: the platform is free, but Meta only permits standard messages inside a 24-hour window from the customer's last message, and every new customer message reopens it. Outside that window you may only send a few approved message-tag types. The follow-up flow therefore has to be designed differently from Zalo, which is extra work rather than a copy-paste.

Each chat channel has its own constraints, so deployment cost differs. Illustration generated with AI.

How much does chatbot development for a website cost?

Since the website is the most-asked channel, here are its numbers separated out. The three tiers below apply to a small or mid-size sales or service website, and already reflect what makes this channel distinct: no platform fee, a single widget embed, and session-only context.

• Scripted chatbot embedded as a widget: roughly 5 - 10 million VND setup, the lower half of the 5 - 15 million range because there are no platform constraints like Zalo's or Meta's to engineer around. Fits opening hours, price lists and policies served through button-driven flows.
• Subscription AI chatbot embedded on the site: close to zero setup, then a few hundred thousand to a few million VND a month. The fastest way to get a bot that understands free-form questions, at the cost of shallow access to your own data and brand voice.
• Custom AI agent for the website: from tens of millions of VND, covering normalized price and policy data, Vietnamese voice training, and connections to your order or booking system. Monthly running cost is the AI model plus hosting, growing with traffic.

What nudges a website quote upward is not the widget itself but what sits behind it: customers logging in for personalized prices, real-time stock lookups, or a multilingual site. Each of those pushes the project from the scripted tier toward a custom agent.

How is a chatbot's monthly AI fee calculated?

AI model fees are charged per token, not per customer. For a concrete figure, take a shop with 3,000 conversations a month, 8 exchanges each. On every exchange the bot rereads its instructions, product data and chat history, roughly 5,000 input tokens, then replies with about 150 tokens. That adds up to 120 million input tokens and 3.6 million output tokens a month. Using the official Gemini API pricing and Vietcombank's selling rate of 26,110 VND per USD on 14 September 2026:

Model and setup	Price per 1 million tokens (in / out)	Monthly fee
Gemini 3.8 Flash until 31 Dec 2026	0.75 / 3.75 USD	about 103.5 USD, or 2.7 million VND
Gemini 3.8 Flash from 1 Jan 2027	1.50 / 7.50 USD	about 207 USD, or 5.4 million VND
Gemini 3.8 Flash with context caching until 31 Dec 2026	cached portion 0.075 USD	about 40 USD, or 1.05 million VND
Gemini 3.5 Flash-Lite	0.30 / 2.50 USD	about 45 USD, or 1.17 million VND

Two takeaways for reading a quote. First, almost all the money sits in input tokens, so context caching (storing the fixed instructions so they are not billed at full price on every exchange) cuts the fee by about 60%, more than switching to a cheaper model. Ask the vendor directly whether it is enabled. Second, Google has announced that Gemini 3.8 Flash prices double from 1 January 2027. A bot running at 2.7 million VND a month becomes 5.4 million VND with nothing changed. A quote signed in 2026 should state who absorbs that increase. These figures exclude hosting and platform message fees and only hold for the traffic assumed above; twice the chat volume means roughly twice the fee.

What actually drives a chatbot quote up?

Not the number of questions the bot can answer, but four things people rarely ask about when requesting a quote. Understand these four and two quotes that differ threefold stop being a mystery.

1. How clean your data is. If your price list lives across screenshots and old chat threads, someone has to normalize it first. This is usually the largest line item and the one most often left out of a quote.
2. Number of integrations. A bot that only replies is cheap. A bot that checks stock, creates orders, books appointments or writes to your CRM adds a discrete block of work per connection, plus risk whenever the other system changes.
3. How much the bot may decide on its own. Closing orders and applying discount codes requires a control layer, audit logs and clear handoff thresholds. A purely advisory bot needs none of that.
4. Language and voice. Vietnamese shifts pronouns by context and is full of abbreviations and typos. Getting a bot to sound human requires dedicated training rather than defaults, as we cover in why Vietnamese AI agents need their own training.

Which costs sit outside the quote but still get paid?

The three items below rarely appear on the first page of a quote, yet they always surface within the first six months. Add all three before comparing two vendors.

• Your own team's time. Someone has to answer product questions, approve sample replies and correct what the bot gets wrong in month one. Usually a few dozen hours.
• Platform message fees. On Zalo that means messages outside the 48-hour window, plus a per-template fee whenever you reach a customer by phone number through ZBS Template Message, which replaced ZNS on 1 January 2026. SMS is charged the same way, per message sent. This scales with customer volume, so it easily overshoots the estimate.
• Maintenance when data sources change. New prices, a new returns policy or a redesigned website all mean touching the bot. Ask explicitly whether this is billed monthly or per request.

Reading a quote: 5 items it must contain

A quote missing these will almost certainly grow past its final number. Take this list to the table before you sign.

1. Conversation scope. How many topics the bot handles, who it hands off to beyond them, and how fast.
2. Data sources and owner. Who normalizes the price list, policies and stock, and on what refresh cadence.
3. A specific integration list. Name the actual systems, not a vague "CRM integration".
4. Monthly running cost, itemized separately. AI model fees, platform message fees and hosting must be split out from setup. Name the model, whether context caching is used, and who pays when the model provider raises prices.
5. Handover and warranty. Who edits flows after launch, free for how long, and at what rate afterwards.

Read all five items carefully before signing. Illustration generated with AI.

Build it yourself or hire it out?

The answer depends on whether you have an operator, not on budget. If someone on your team knows the tooling and will own weekly bot edits, building on an existing platform is sensible and much cheaper. If nobody will take that job, a bot built once and abandoned will answer wrong and lose customers faster than having no bot at all. For teams without an operator, outsource the setup but keep the right to edit content, and insist on being handed the root accounts from day one. To size the revenue you are currently losing to slow replies before committing a budget, use the AI agent ROI calculator.

Frequently asked questions