One of the biggest questions we get at Velt is how much a commenting SDK costs. People want to know what they should expect to pay, what building in-house can cost, and more. We’ve helped hundreds of product teams sort out those numbers, and this guide is meant to help you not pay more than you need to.
TLDR:
Commenting SDK prices vary by feature depth, usage metric, and hosting model.
Vendors charge in different ways: Monthly Active Users (MAU), Monthly Active Collaborators (MAC), or comment/bandwidth volume.
Velt charges by monthly active collaborators, so you only pay for users who use the features.
Liveblocks charges by all monthly active users, so you have to pay for everyone signed in.
The biggest hidden fee is developer time. Building from scratch can top $450k in year one.
How Pricing Models Work in Practice
There are a few different pricing models that comment SDKs and related products offer.
1. Monthly Active Users (MAU)
What counts: Every signed-in user in a given month, even if they don't use the collaboration features.
Who uses it: Liveblocks
Pain point: Paying for a user that never used the commenting features makes no sense, especially if you have a lot of users who don't use or need the collaboration tools.
2. Monthly Active Collaborators (MAC)
What counts: Only people who perform CRUD operations like post, reply, react, or read.
Who uses it: Velt ⬅️ that's us
Advantage: You pay only for users who actually use the collaboration features.
3. Document/Comment Volume or Storage
What counts: Total objects saved or simultaneous connections.
Who uses it: Some headless BaaS databases and home-grown stacks. Tiptap prices on documents in their cloud.
Risk: A single viral thread can blow past tiers unless your limits are generous.
Reality check: On a design tool with 100k MAU, only 15k people might comment in any given month. Choosing MAC can slice the bill by more than 70%.
By the way, we've already done a full breakdown of the best commenting SDK (including cost, features, security, etc). Check it out if you're seriously considering.
The Hidden Costs Vendors Rarely Mention
Bandwidth overages: Real-time presence pings add up. Check how many comments and simultaneous connections are allowed. Velt's pricing has the most generous free tier.
Feature gates: Some vendors put customization or comment types behind enterprise tiers.
Support delays: If your only help line is an email inbox, a broken web RTC config can stall users for hours. Velt has Slack support by the way 😄.
Quick Note: Build vs Buy Cost
We talk to a lot of people who think about rolling their own. We actually wrote a full commenting SDK build vs buy guide, but one big thing here is that subscription number doesn't tell the whole story. The engineering hours alone required upfront, to maintain, and to build all the new features people request can get insane. If you only focus on a subscription fee, you may free up budget today only to watch the bill snowball later.
The Four Parts of Commenting Feature
Code and Design Time: UI component design + build, permission checks, offline sync edge cases.
Runtime Infrastructure: Secure WebSocket gateways, auto-scaling worker pools, database writes, and cold storage.
Feature Add-Ons: Presence, mentions, emoji reactions, read receipts, voice notes, email digests, and task management.
Vendor Plan or Cloud Bills: Recurring SaaS plan or cloud resource spend if you self-host.
Where the Money Actually Goes
Line Item | Build In-House Year 1 | Velt MAC-Based Plan |
|---|---|---|
Engineering salaries (back-end, front-end, QA) | $320k | $10k integration sprint |
Real-time infra (servers, bandwidth) | $48k | Included |
Monitoring, alerts, incident duty | $18k | Included |
Compliance reviews | $20k | Included |
Annual vendor fee | $0 | Starts at $24K |
Year-one total | $406k | $34k |
Building looks “free” until you tally the paychecks. A ready-made SDK drops the real-time headache squarely on the vendor’s shoulders.
How Velt Keeps Bills Predictable
MAC metric: You are not billed for anyone who doesn't use the commenting feature.
Generous base limits: 200 M comments and 2TB before overage vs 100K and 8GB on many rivals.
Flat real-time rate: Presence and cursor pings are covered, no per-socket surprise.
Dual deployment: Cloud for speed or self-host data for compliance. Same feature set, same API.
Slack support: Get a reply in minutes, which means fewer outages eat dev hours.
Why Slack Support Lowers Your Cost
A 30-minute production incident can cause churn + increased engineering hours. Talking to an engineer in real time often beats waiting in an email queue.
Framework to Pick the Right Plan
Follow these steps before signing:
Calculate Active Collaborators: Run a quick query: how many distinct users will be using the features?
Project Growth Curve: Multiply that number by a realistic growth factor, not just signup goals.
Estimate Comment Storage: Average comment size × expected threads × retention period.
Check Region Needs: If you hold EU resident data, pick a vendor that offers EU hosting or self-host.
Read Support SLAs: 99.99% uptime sounds fine until you ask which incidents count toward it.
Figure out what features you need: most teams start with a commenting SDK and then end up wanting notifications, huddles, and much more.
Using that framework, most SaaS teams land on MAC pricing and high storage caps...both strong points for Velt.
Cost Pitfalls and How to Avoid Them
Ignoring read-only users on MAU tiers: You will pay for every marketing funnel sign-in.
Forgetting compliance audits: Self-hosting can wipe out third-party review fees.
Buying a “starter” tier: Moving up one tier later can double or triple price by design. Plan for year-two numbers now.
Frequently Asked Questions
How do I predict MAC or MAU before go-live?
Look at similar features you already run (comments in docs, chat rooms, ticket replies). Multiply daily authors by 1.5 to cover seasonal peaks.
Is self-hosting always more expensive?
Not if your compliance team requires it. The hosting bill can still be lower than fines or custom audit projects.
Can I switch from SaaS to self-host later?
With Velt, yes. Your data is your data. You can self-host sensitive info, and we only store identifiers.
Does Velt limit frameworks?
No. Velt is framework agnostic, so it works with React, Vue, Svelte, Angular, etc. You avoid the “only React” roadblock that comes with many tools.
Linking Cost to Feature Depth
Some teams think “cheapest wins,” but missing features force workarounds:
Task management and workflow features: Don't just provide commenting but a complete end to end useful experience.
Notifications: We've seen that people want this right alongside commenting. Velt has in-app, email, and webhook notification options.
Thread resolution: If closed comments linger, people stop trusting the tool.
Video huddles or screen recording: Adds stickiness and deflects meetings.
Presence and cursors: Without them, users ask “who is editing right now?”
Buying a bare-bones comment API saves dollars short-term, but usually triggers a rewrite next quarter. Velt bakes those extras in from day one.
Conclusion: Choose Predictable Costs Over Sticker Shock
An in-app comment feature drives product stickiness, but the price tag can balloon if you pick the wrong metric or forget the long list of hidden fees. We’ve looked at how engineering time, real-time bandwidth, storage, and compliance all feed into total cost. Models based on Monthly Active Users punish apps with large viewer bases. A MAC plan, generous storage, and region flexibility line up far better for most SaaS products.
Velt offers MAC pricing, high comment and storage caps, real-time bandwidth built in, and the option to self-host gives you room to grow without nasty surprises. Feel free to take a closer look at the commenting SDK from Velt. The numbers speak for themselves.
