Subscription vs Pay-as-You-Go vs Top-Up — A WebRTC Billing Decision Framework for 2026

Three pricing shapes dominate WebRTC in 2026: monthly subscriptions (LiveKit Ship/Scale, TRTC Lite/Standard/Pro, Agora Starter/Pro/Business), pure pay-as-you-go (Daily.co, 100ms, Agora's PAYG mode), and prepaid Top-Up packs with 1-year validity (TRTC's 25k / 250k / 1M packs, Agora's prepaid balance). Most decision posts compare per-minute rates. The real decision is structural: which mode tolerates your volume variance, fits your cash flow, and absorbs your bursts. This guide gives you a 4-quadrant decision tree, three worked-example workloads, and an explicit "which vendor lets you stack what" matrix — so you stop overpaying for unused commitments and stop getting blindsided by spikes.

The decision in one chart

                     LOW variance              HIGH variance
                ┌───────────────────────┬─────────────────────────┐
   HIGH         │  Monthly subscription │  Top-Up + PAYG fallback │
   monthly      │  (you always fill it) │  (size to peak, drain   │
   volume       │                       │   slowly)               │
                ├───────────────────────┼─────────────────────────┤
   LOW          │  Free tier + small    │  Free tier + small      │
   monthly      │  Top-Up safety net    │  Top-Up + PAYG          │
   volume       │  ($23 once)           │  (insurance + uncapped) │
                └───────────────────────┴─────────────────────────┘

If you can place yourself in one of the four quadrants, the rest of this guide tells you the per-vendor implication.

The three billing shapes, and what they each really cost you

1. Monthly subscription

The shape: You pay a fixed fee per month. The fee includes a quota of minutes / sessions / agent minutes. Overage is metered. Unused quota does not roll over.

Examples: LiveKit Ship ($50/mo, 150k WebRTC min) and Scale ($500/mo, 1.5M); TRTC Lite ($49.5/mo, 50k), Standard ($499/mo, 500k), Pro ($1,499/mo, 1.5M); Agora Starter ($45.99/mo) through Business Plus ($1,217.99/mo); Zoom Build Platform ($100/100 credits or $450/500 credits per month).

The cost you actually pay: The headline rate. Plus the opportunity cost of unused minutes. If your Lite plan includes 50k and you used 38k, you paid for 12k you'll never get back. Across a year of variable usage, this dead weight is typically 15–35% of the bill.

The cost you can't see on the pricing page: Lock-in. Once you've committed to a tier, downgrading mid-cycle is messy on most platforms (Agora explicitly only allows once-per-month downgrades; Zoom credit packs are tied to the subscription month). A surprise quiet quarter still costs you full freight.

2. Pay-as-you-go (PAYG)

The shape: No monthly fee. You're billed per minute consumed, at a published rate.

Examples: Daily.co ($0.004/participant-minute video+audio, with graduated discount kicking in at 100k/mo); 100ms's Pay-As-You-Grow; Agora's pure PAYG mode ($0.99/1k audio, $3.99/1k HD video); TRTC's post-paid toggle ($0.99/1k audio).

The cost you actually pay: Exactly your usage at full rate. No discount unless you hit a graduated tier (Daily) or post-paid volume threshold.

The cost you can't see on the pricing page: The bill spike. PAYG is correlated with whatever's happening in your product — bot traffic, viral moment, marketing campaign — without any cap. Most engineering teams who switch to pure PAYG eventually rebuild their billing dashboards because they've learned the hard way that revenue-per-minute and cost-per-minute don't always line up with usage spikes.

3. Prepaid Top-Up packs

The shape: You buy a fixed pack of minutes for a flat fee, valid for 12 months. No recurring fee. No auto-renew. Stackable with PAYG and (on TRTC) with subscriptions.

Examples: TRTC Top-Up (25k/$23, 250k/$225, 1M/$870, all 1-year validity); Agora prepaid plans (account-balance model, also 1-year validity for top-ups); enterprise reserved capacity (LiveKit Enterprise — non-self-serve).

The cost you actually pay: Pack price ÷ minutes used. If you buy a 250k pack at $225 and use 200k, your effective rate is $1.125/1k — you've paid more than PAYG's $0.99/1k. If you use 250k, it's $0.90/1k — 9% cheaper than PAYG. If you use 50k, you've thrown $180 away.

The cost you can't see on the pricing page: The forecasting risk. You're betting on your 12-month minute consumption. Bet too high, you've prepaid for nothing. Bet too low, you're back at PAYG faster than you wanted. The mitigation: start with the smallest pack (25k/$23) as insurance and only scale up after you've measured a quarter of real traffic.

Decision dimension 1: Volume predictability

The rule: subscriptions only make sense if you'd be embarrassed by how full the bucket isn't. If you'd be paying for 70%+ utilization, the subscription is honest. If you'd be paying for 30% utilization, you're subsidizing the vendor.

Decision dimension 2: Cash flow style

Top-Up is the only shape that gives both the "no recurring opex drag" of PAYG and the "I know my max bill" of a subscription. That's why it's the natural fit for the messy middle: post-MVP, pre-enterprise, growing without easy revenue forecasting.

Decision dimension 3: Burst handling

This is the dimension most pricing posts ignore.

A "burst" — a 3× normal day — is a different problem in each model:

• Subscription: You burn through your included quota faster than expected. Overage rate kicks in (typically $0.99/1k or whatever the post-paid rate is), so you pay for the spike. Your base fee was already paid, so you're paying twice.
• PAYG: You pay full freight on every spike-minute. Your bill scales with the spike's size. If the spike is 100x normal, your bill is 100x. (This is the number that wakes engineering managers up at 4 AM.)
• Top-Up + PAYG: The Top-Up pack absorbs the spike up to its size. Beyond that, PAYG continues at full rate. The pack is your buffer. A 25k pack covers 5,000 minutes/day for 5 days of unexpected traffic at $0.92/1k — a $4.60 cost per spike-day vs. $4.95 on PAYG.

For demo and beta-stage products that need predictable maximum bills during launch weeks, the Top-Up + PAYG combo is structurally better than either subscription or PAYG alone.

How "stackable" each vendor's billing modes are

The other axis is which modes can run simultaneously on the same account. This is where vendor flexibility actually differs — much more than headline rates.

Why this matters: If you want to insure a quiet base-load with a subscription and protect against spikes with a Top-Up and keep PAYG as the ultimate fallback, only TRTC supports all three on one account at the same time. Other vendors force you to pick.

For a per-vendor breakdown, see our deep-dives: LiveKit Pricing 2026, Agora Pricing 2026, Daily.co Pricing 2026, Zoom Video SDK Pricing 2026.

Three worked examples

Example 1: Indie product builder, 4–8k min/mo

You're solo or two-person, your product handles ~5,000 RTC minutes most months and occasionally spikes to 15,000 during a feature launch.

Top-Up wins by a factor of 12 vs LiveKit Ship and 12 vs Daily.co PAYG.

Example 2: Growth-stage SaaS, 50k min/mo with quarterly spikes to 120k

You've raised a Series A, traffic is climbing, and quarterly enterprise demos drive 2–3 spike weeks.

Annual total: 12 × 50,000 + 3 × 70,000 (spike-overage) = 810,000 RTC minutes.

Top-Up wins on cost; LiveKit Ship wins on simplicity if you're committed to one platform. TRTC's Lite + overage is competitive with Top-Up here ($802 vs $870), so the choice comes down to whether you prefer one upfront payment or 12 small monthly bills.

Example 3: Enterprise call center, ~500k min/mo with a baseline that varies ±20%

You've hit enterprise scale. Volume is high but variance is real.

Annual total: 12 × 500,000 ± 20% = 5–7 million RTC minutes.

At enterprise scale, the conversation moves to dedicated commercial terms. Top-Up packs remain useful as a way to true-up specific months or hedge variability, but the dominant decision is the annual contract.

Why TRTC made Top-Up self-serve in 2026

The vendor-side reason is alignment with how teams actually buy infrastructure now.

For most of the 2010s, RTC pricing was either (a) annual enterprise commit or (b) raw PAYG. Subscription tiers came later and tried to bridge the gap, but they encoded a vendor assumption: "you commit to a monthly bucket, we get predictable revenue." That assumption broke down when usage patterns started to vary more — seasonal apps, viral spikes, agent-built workloads with irregular customer distribution, AI-amplified traffic.

A prepaid pack with 1-year validity is the structural compromise: predictable for the buyer, recoverable for the vendor. It's why both TRTC and Agora rolled out top-up models in 2025–2026, and why LiveKit and Daily.co haven't (their architecture commits to subscription / PAYG respectively).

FAQ

Should I switch from a subscription to Top-Up? Run the math: take your last 12 months of RTC minutes, compute (subscription fees + overage). If a Top-Up pack of comparable size is at least 10% cheaper, switch. If it's within 5%, the convenience of a recurring invoice may be worth keeping the subscription.

Can I run pay-as-you-go and a credit pack at the same time? On TRTC, yes — PAYG is the fallback after both subscription minutes and Top-Up minutes are exhausted. On Agora, partial — the prepaid balance must be exhausted before PAYG triggers, and you can't always have both active at once. On LiveKit, PAYG is itself part of subscription overage; there's no separate "PAYG mode."

What if I exhaust my Top-Up balance during a critical period? With PAYG enabled, service continues at standard rates ($0.99/1k audio on TRTC). With PAYG disabled and no other coverage, service suspends until you add billing. The recommended setup is to keep PAYG on as a permanent backstop.

Does the Top-Up cover Conversational AI / TTS / STT? On TRTC, no — Top-Up is RTC-only. AI services have their own metering (Conv AI $0.01/min, STT $0.02/min, AI translation $0.016/min, TTS $0.6/10k chars), with the 10,000-min monthly free pool converting at documented ratios.

How does Top-Up affect my SLA / support tier? Top-Up gives you minutes, not feature unlocks. Plan-tier features (priority support response times, AI noise suppression, advanced video resolutions) remain gated to subscription tiers. If you need a Pro-tier SLA, you'll need a Pro subscription — even with a 1M Top-Up sitting on the account.