Direct answer: at Azure SignalR Service public list prices on 10 November 2026 (eastus, USD, excluding tax and discounts), Standard is $1.61 per unit per day and Premium is $2.00 per unit per day; at 30.5 days, one unit is about $49.11 (Standard) / $61.00 (Premium) per month. One unit = 1,000 concurrent connections (Free has only 20), and the first 1,000,000 outbound messages per unit per day are free; beyond that, $1 per million messages. Only outbound messages are billed; inbound is free, pings are ignored, and messages larger than 2 KB count as multiples of 2 KB. A broadcast to N clients is N outbound messages. Standard caps at 100 units (100,000 connections) with a 99.9% SLA; Premium caps at 1,000 units with a 99.95% SLA and adds availability zones, autoscale, custom domains and geo-replication; above 100 units requires Premium_P2.
This guide is for architects, backend/frontend engineers, SRE, finance and procurement choosing a real-time push/long-connection service, evaluating SignalR versus self-hosted WebSockets, or sizing an existing SignalR instance. It separates official prices, editorial calculations and exclusions, covering units and connections, outbound messages and the 2 KB rule, the Standard/Premium gap, broadcast fan-out, combined TCO and a 90-day checklist. Prices come from the SignalR pricing page, Azure Retail Prices API and Microsoft Learn billing/performance docs (10 November 2026). This is not procurement advice.
(1) Units buy connection capacity, not message volume: one unit is 1,000 connections and bills per unit/day; add units only when connections run short. (2) Messages are outbound only, but broadcast fan-out multiplies them: 1,000 recipients means 1,000 messages, and 4 KB doubles that. (3) Adding units purely for messages is poor value: an extra unit adds 1M messages/day for about $1.61, while overage is $1/million; size units by connections, then compare overage with extra units.
Billing model: units, connections and messages
SignalR billing has two parts: connection capacity (units/day) and outbound messages. Free gives 20 concurrent connections, 20,000 messages/day, at most 1 unit and no SLA; Standard gives 1,000 connections per unit, the first 1,000,000 messages per unit per day free, at most 100 units and a 99.9% SLA; Premium also gives 1,000 connections per unit, at most 1,000 units, a 99.95% SLA, and adds availability zones, autoscale, custom domains and geo-replication. Microsoft bills per second; the pricing page estimates a month at 30.5 days. Connection counts include server, client and diagnostic connections, while live-trace connections are not counted.
| Tier | Connections/unit | Messages/unit/day | Unit price/day | Max units | SLA |
|---|---|---|---|---|---|
| Free | 20 | 20,000 | $0 | 1 | None |
| Standard | 1,000 | First 1M free, then metered | $1.61 | 100 | 99.9% |
| Premium | 1,000 | First 1M free, then metered | $2.00 | 1,000 | 99.95% |
Sources: SignalR pricing page and Retail API (eastus, 10 November 2026). Unit prices are per day and billed per second; monthly estimates use 30.5 days. Above 100 units requires Premium_P2 (performance doc).
Capacity cost: 1/2/6/11/51/101 units
At 30.5 days: 1 unit is $49.11 Standard / $61.00 Premium; 2 units $98.21 / $122.00; 6 units $294.63 / $366.00; 11 units $540.16 / $671.00; 51 units $2,504.36 / $3,111.00. Standard maxes at 100 units = 100,000 connections and $4,910.50; beyond that only Premium: 101 units is $6,161.00 and 1,000 units is $61,000. Capacity planning must leave room for server connections: each app server starts with 5 connections per hub, and ASP.NET SignalR adds 5 more for the default hub; 5,000 clients need at least 6 units (6,000 capacity), not exactly 5.
| Units | Connection capacity | Standard/month | Premium/month | Fit |
|---|---|---|---|---|
| 1 | 1,000 | $49.11 | $61.00 | Small/staging |
| 2 | 2,000 | $98.21 | $122.00 | 1,000 clients + server connections |
| 6 | 6,000 | $294.63 | $366.00 | 5,000 clients |
| 11 | 11,000 | $540.16 | $671.00 | 10,000 clients |
| 51 | 51,000 | $2,504.36 | $3,111.00 | 50,000 clients |
| 101 | 101,000 | Above Standard limit | $6,161.00 | 100,000 clients, Premium only |
| 1,000 | 1,000,000 | — | $61,000.00 | Premium ceiling |
Editorial calculation: units × unit price × 30.5 days; excludes message overage, tax and discounts. Capacity includes server/client/diagnostic connections; leave 20%–30% headroom on peak connections and server connections.
Messages: outbound, 2 KB and broadcast fan-out
Only outbound messages are billed: an app-server message into the service is free inbound, while service-to-client is billed; when client A messages client B, the service-to-B leg is billed; pings are ignored. Messages larger than 2 KB count as multiples of 2 KB: 4 KB counts as 2, 6 KB as 3. Broadcasts fan out by client: a 1 KB broadcast to 1,000 clients is 1,000 messages; 4 KB to 1,000 clients is 2,000. The first 1,000,000 messages per unit per day are free, then $1 per million. Example: 6 units with 10M outbound/day gives 6M free, 4M over × 30.5 = 122M messages = $122/month, plus $294.63 units = $416.63.
| Outbound/day | Units | Free/day | Overage/month | Overage fee | Total/month |
|---|---|---|---|---|---|
| 1M | 1 | 1M | 0 | $0 | $49.11 |
| 5M | 1 | 1M | 122M | $122.00 | $171.11 |
| 10M | 6 | 6M | 122M | $122.00 | $416.63 |
| 50M | 10 | 10M | 1,220M | $1,220.00 | $1,711.05 |
| 100M | 10 | 10M | 2,745M | $2,745.00 | $3,236.05 |
Editorial calculation: Standard $1.61/unit/day × 30.5 days; overage = max(0, daily volume − units × 1M) × 30.5 × $1/million. Excludes Premium, tax and discounts; bills follow actual usage.
Standard vs Premium: $71.37 more for 6 units
Premium costs $0.39 more per unit per day: 6 units is $294.63 Standard versus $366.00 Premium, $71.37 more per month (+24.2%). In return you get availability zones, fully managed autoscale, custom domains, geo-replication, and a 99.95% SLA instead of 99.9%; Standard caps at 100 units while Premium reaches 1,000. If the workload is single-region, 99.9% is acceptable and scaling is manual, Standard is enough; if you need cross-AZ, multi-region or a higher SLA, the $71.37 is usually cheaper than operating multi-region WebSockets yourself—but it scales with unit count.
| Item | Standard | Premium | Impact |
|---|---|---|---|
| Unit price/day | $1.61 | $2.00 | +$0.39 |
| 6 units/month | $294.63 | $366.00 | +$71.37 (+24.2%) |
| SLA | 99.9% | 99.95% | Higher availability |
| Availability zones | No | Yes | Cross-AZ resilience |
| Autoscale | No | Yes | Scale with load |
| Custom domain/geo-replication | No | Yes | Multi-region/brand domain |
| Max units | 100 | 1,000 | 100k vs 1M connections |
Source: SignalR pricing page (10 November 2026). Editorial calculation: 6 units × 30.5 days; the gap excludes message overage, tax and discounts; multi-region deployments should be checked against the actual architecture.
Selection matrix and hidden costs
Choose by stage: Free for dev/demo (20 connections, 20k messages/day, no SLA); Standard 2–6 units for small production; Standard up to 100 units for single-region mid/large workloads; Premium for AZ, geo-replication, 99.95% or more than 100,000 connections. Eight hidden costs: server connections consume capacity, broadcast fan-out multiplies messages, the 2 KB multiplier, no SLA on Free, Premium +24%, staging/test units running 24/7, above 100 units requiring Premium_P2, and duplicate units in multi-region deployments. 90 days: weeks 1–2 measure peak connections (client + server + hubs); weeks 2–3 measure daily outbound, message size and fan-out; weeks 3–4 size units with 20%–30% headroom; weeks 4–6 load-test broadcast and message overage; weeks 6–8 evaluate AZ/geo/SLA; weeks 8–10 shut down idle staging and verify per-second billing; weeks 10–12 reconcile the bill and set budget alerts.
| Scenario | First choice | Check first |
|---|---|---|
| Dev/demo | Free | 20 connections, 20k messages/day, no SLA |
| Small production | Standard 2–6 units | Server connections, peak |
| Single-region mid/large | Standard by connections | 100-unit cap |
| Cross-AZ/multi-region | Premium | +24%, replication design |
| Broadcast/large fan-out | Optimize messages first | Fan-out, 2 KB multiples |
| Above 100k connections | Premium/P2 | Premium_P2 specs |
| Staging/test | Turn on demand | Per-second billing, avoid 24/7 |
Editorial summary, not a vendor recommendation; features, limits and SLAs follow the official pricing page/docs; multi-region cost needs architecture-specific validation.
FAQ
How is Azure SignalR billed?
Two parts: connection capacity per unit/day (Standard $1.61, Premium $2.00; one unit = 1,000 connections), and outbound messages with the first 1M per unit per day free and $1 per million after that. Billing is per second; monthly estimates use 30.5 days.
How many connections does one unit support?
Standard/Premium support 1,000 concurrent connections per unit; Free has only 20. Counts include server, client and diagnostic connections; server connections take 5 per app server per hub, and ASP.NET SignalR adds 5 for the default hub.
How are messages counted?
Outbound only: service-to-client/app-server messages are billed, inbound is free, pings are ignored. Above 2 KB counts as multiples of 2 KB; a broadcast to N clients is N messages. The first 1M per unit per day is free, then $1 per million.
How many messages is a broadcast to 1,000 clients?
A 1 KB broadcast to 1,000 clients is 1,000 outbound messages; a 4 KB message counts as 2 per client = 2,000. Compressing or splitting payloads under 2 KB directly reduces billed messages.
Is the 1M free allowance per unit or per instance?
The official column is per unit per day: 6 units give 6M messages/day free, 10 units give 10M/day; beyond that, $1 per million messages.
What is the price gap between Standard and Premium?
$0.39 per unit per day; 6 units is $294.63 Standard versus $366.00 Premium, $71.37/month more (+24.2%). Premium adds availability zones, autoscale, custom domains, geo-replication and a 99.95% SLA, and raises the unit cap from 100 to 1,000.
What happens above 100 units?
Standard caps at 100 units (100,000 connections); 101 and above requires Premium, and the performance doc requires Premium_P2 above 100 units. A rough Premium 101-unit estimate is $6,161/month; confirm P2 price and capacity on the official page/contract.
How do I reduce cost?
Five steps: (1) buy units for peak connections, not for messages; (2) compress broadcasts under 2 KB and reduce fan-out; (3) turn staging/test on demand and use per-second billing; (4) use Standard when single-region 99.9% is acceptable instead of defaulting to Premium; (5) compare extra units with overage—for pure message volume, $1/million is usually cheaper than a new unit at $1.61/day.
Research method and limitations
Official facts (pricing page, Retail API, Learn billing/performance docs): Standard $1.61/unit/day, Premium $2.00; one unit = 1,000 connections; Free 20 connections/20k messages/day/1 unit; first 1M outbound messages per unit per day free, then $1/million; outbound only, 2 KB multiples, broadcast by client count; Standard 100 units/99.9%, Premium 1,000 units/99.95%; above 100 units requires Premium_P2. Editorial calculations: 30.5 days/month, units × unit price, overage = max(0, daily volume − units × 1M) × 30.5 × $1/million.
Seven limitations: (1) eastus USD list prices only, excluding tax/contract discounts/regional differences; (2) connection peaks, message volume, fan-out and message size are editorial assumptions; (3) excludes app servers/VMs, bandwidth, Redis backplane, monitoring and labour; (4) no real long-connection/broadcast/failover benchmark; (5) Premium_P2's separate price and capacity are not quoted here; (6) multi-region/geo-replication billing needs architecture-specific validation; (7) prices/limits change—recheck official pages and bills before purchase.
Sources and basis
- Microsoft Azure, Azure SignalR Service Pricing: azure.microsoft.com/en-us/pricing/details/signalr-service. Free/Standard/Premium, connections/unit, message allowance, unit caps, SLA, Premium features. Accessed 10 November 2026.
- Azure Retail Prices API (productName eq SignalR, eastus): prices.azure.com/api/retail/prices. Standard $1.61/unit/day, Premium $2.00, messages $1/million. Accessed 10 November 2026.
- Microsoft Learn, Messages and connections in Azure SignalR Service: signalr-concept-messages-and-connections. Outbound-only billing, 2 KB multiples, broadcast counting, connection counting. Accessed 10 November 2026.
- Microsoft Learn, Performance guide for Azure SignalR Service: signalr-concept-performance. Units vs connections/throughput, Premium_P2 above 100 units. Accessed 10 November 2026.
Data cut-off 10 November 2026; prices/features follow Microsoft official pages and bills; this is not procurement, architecture or legal advice.