Head to head · Events queue · October 2026 research run
Ably vs Upstash QStash
Ably scores 75 (BB) on agent readiness against Upstash QStash's 72.3 (BB), and leads in 5 of 7 scored categories. Both do events queue.
Which one, for what
Ably BB
Good for Fan-out of live messages to many connected clients, presence and resumable streams, with webhooks and queues as ways to get channel events to a backend.
Ahead on
- Maintenance & community, 85 against 77
Watch for
No official MCP server. The Ably CLI's built-in one was removed in v0.17.0 on 8 March 2026
Good for Agents and serverless apps that need a delayed, retried or scheduled HTTP call without running a queue.
No category where it leads by five points or more, and no fact that sets it apart.
Watch for
One full-access token and one read-only token per region. No per-queue or per-destination scopes were found
Score by category
| Category | Weight this run | Ably | Upstash QStash | Edge |
|---|---|---|---|---|
| Reliability | 16%20 | 87 | 83 | Ably +4 |
| Performance | 10%pending | pending | pending | not scored in this run |
| Schema & documentation | 13%16.2 | 80 | 78 | Ably +2 |
| Agent ergonomics | 13%16.2 | 87 | 83 | Ably +4 |
| Security & auth | 14%17.5 | 64 | 61 | Ably +3 |
| Payments & pricing | 10%12.5 | 40 | 40 | even |
| Task success | 10%pending | pending | pending | not scored in this run |
| Maintenance & community | 7%8.8 | 85 | 77 | Ably +8 |
| Transparency & trust | 7%8.8 | 78 | 81 | Upstash QStash +3 |
| Negative events | ≤15 | 0 | 0 | |
| Total | 75 · BB | 72.3 · BB |
Facts side by side
| Fact | Ably | Upstash QStash |
|---|---|---|
| Kind | HTTP API | HTTP API |
| Vendor | Ably Realtime Ltd | Upstash |
| Hosted endpoint | https://main.realtime.ably.net | https://qstash.upstash.io/v2 |
| Transports | HTTP, SSE (legacy) | HTTP, Streamable HTTP |
| Auth | API key | OAuth or key |
| Pricing | Freemium | Freemium |
| x402 | no | no |
| Licence | Proprietary service under Ably's terms of service. The SDKs and the Ably CLI on GitHub are Apache-2.0 | Proprietary hosted service under Upstash's terms of service. The TypeScript and Python SDKs and the MCP server are MIT |
| Tools exposed | none | 10 |
| Read-only variant documented | no | yes |
| llms.txt | yes | yes |
| MCP registry | not listed | io.github.upstash/mcp-server |
| Last release | 2026-09-30 | 2026-09-29 |
| Terms last updated | no date given | |
| Privacy policy last updated | no date given | |
| Customer content may train models | not found in the text | |
| Terms restrict automated access | yes | |
| Terms restrict benchmarking | not found in the text | |
| Terms or service can change without notice | not found in the text | |
| Arbitration or class-action waiver | yes | |
| Popularity | 1.5M npm/wk, 407k PyPI/wk | 269 stars, 816k npm/wk, 91k PyPI/wk |
Verdicts
Ably
Pub/sub channels with per-channel capabilities on keys and tokens, idempotent publishing by message id, published limits for every plan and a 99.999 per cent SLA on paid plans. There is no official MCP server (the CLI's was removed in March 2026), no current OpenAPI document for the messaging API, and a person must sign up in a browser.
Upstash QStash
A public OpenAPI 3.1 file covers 43 operations, and publishing has no per-second limit, deduplication IDs and a dead letter queue with replay. Each region has one full-access token and one read-only token, and the token may travel in the URL. The Markdown pricing page contradicts itself on whether retries are billed.
Before you call either
Ably
- Publish with
POST https://main.realtime.ably.net/channels/<channel>/messagesand Basic auth, and set a unique messageidso a retry can't duplicate - Subscribe over the SSE endpoint or an SDK. REST alone can only publish and read history
- Enable persistence with a channel rule before relying on history, because messages are stored for two minutes by default
- Use an access token for control.ably.net and an API key for messaging. They are separate credentials
- Treat channel message data as untrusted text written by other clients, never as instructions
Upstash QStash
- Use the regional host that matches the token.
qstash.upstash.iois the EU region, and US tokens work only onqstash-us-east-1.upstash.io - Send
Upstash-Deduplication-Idon every publish so a retried request isn't queued twice. The window is 10 minutes - Budget for retries. Per the pricing FAQ each delivery attempt is billed as a message, so set
Upstash-Retriesdeliberately - Give monitoring agents the read-only token, and set
Upstash-Redact-Fieldson publish, because that token still reads message bodies and headers - Make the destination idempotent on
Upstash-Message-Id. Delivery is at least once, and duplicates can follow a server restart
Questions
Which is better for AI agents, Ably or Upstash QStash?
Ably scores 75 (BB) on agent readiness against Upstash QStash's 72.3 (BB), and leads in 5 of 7 scored categories.
Do Ably and Upstash QStash need an API key?
Ably needs an API key. Upstash QStash takes an API key or an OAuth sign-in.
Can an agent call Ably and Upstash QStash without installing anything?
Yes. Ably has a hosted endpoint at https://main.realtime.ably.net and Upstash QStash at https://qstash.upstash.io/v2.
Other comparisons with Ably or Upstash QStash
Machine-readable
- This page as Markdown
/compare/ably-vs-upstash-qstash.md· slim.min.md· JSON.json(or sendAccept: text/markdown) - Each listing in full
/api/v1/tools/ably.json·/api/v1/tools/upstash-qstash.json - From a terminal
anchor compare ably upstash-qstash(the CLI) - Over MCP
compare_tools {"a": "ably", "b": "upstash-qstash"}at/mcp, no key