Confluence is the only option that can meet your under-$15 SSO test, pending a Guard price check; Notion and Coda fail

Scope, interpretation and check date

Check date: 5 October 2026. I read the three options as Notion (notion.so), Coda (coda.io, now rebranded Superhuman Docs) and Confluence Cloud (Atlassian). I treated "under $15/seat" as a pass/fail test on the cheapest plan that also gives SSO and the Jira integration. Acme Docs (acmedocs.com) is not a researchable product: the domain is a parked page, so I added no column, gap table or advantages list. I did not invent a baseline.

Verdict in brief: Confluence is the only option that can meet all three constraints, but the price of its SSO add-on (Atlassian Guard) was not captured, so the under-$15 result is conditional. Notion fails on price (SSO needs Business at $20). Coda fails because SSO needs Enterprise (custom price) and the Jira Pack needs Business or above.

Pricing table

Billing mode shown on live pages was not always stated. Atlassian's own pricing page returned an empty body to my fetch, so Confluence prices come from a third-party article (July 2026) and the billing mode is unconfirmed. I list the figure under annual and mark monthly "Not captured".

Option	Plan	Monthly price (annual)	Monthly price (monthly)	Unit	Key limits	Free tier/trial	Changed in 6 months
Notion	Free	$0	$0	member	Block limit for multi-member workspaces	Yes	No: same prices on 1 Apr 2026 capture
Notion	Plus	$10	Not captured	member	API 180 requests/min	Free plan	No (same capture)
Notion	Business	$20	Not captured	member	API 600 requests/min	Free plan	No (same capture)
Notion	Enterprise	Contact sales	Contact sales	member	SCIM API	No	No (same capture)
Coda / Superhuman Docs	Pro	$12	$15	Doc Maker	Automations 100 time-based and 500 event-based per doc	Free plan	Yes: new-customer list prices rose in July 2026 (third-party source, vendor page unreadable)
Coda	Business (formerly Team)	$33	$40	Doc Maker	Unlimited automations	Free plan	Yes (same source)
Coda	Enterprise	Contact sales	Contact sales	Doc Maker	SSO, SCIM	No	Unknown (no capture)
Confluence	Free	$0, up to 10 users (third party)	$0	user	2 GB storage	Yes	Unknown (no capture)
Confluence	Standard	$5.42 (third party)	Not captured	user	250 GB; 100 automation steps/user/month	Trial link	Unknown (no capture)
Confluence	Premium	$10.44 (third party)	Not captured	user	Unlimited storage; 99.9% uptime SLA	Trial link	Unknown (no capture)
Confluence	Enterprise	Contact sales (billed annually)	Contact sales	user	Guard Standard included	No	Unknown (no capture)
Confluence add-on	Atlassian Guard Standard (SSO, SCIM)	Not captured	Not captured	user	Price not captured	Trial link	Unknown (no capture)

Coda bills only Doc Makers; editors and viewers are free. That lowers real cost for read-heavy teams. Coda's live price table would not load, so every Coda price rests on a third-party tracker, which a second tracker repeats ($12/$15 Pro, $33/$40 Business). Treat Coda prices as unverified against the vendor page.

Constraint tests

Constraint	Notion	Coda	Confluence
Under $15/seat including SSO	Fail: SAML SSO sits on Business at $20; even a 17% yearly discount would not reach $15 (my inference)	Fail: SAML SSO is Enterprise only, price custom	Conditional: Standard $5.42 and Premium $10.44 (third party) leave $9.58 and $4.56 of headroom for the Guard add-on (my arithmetic). Guard's price was not captured, so SSO under $15 is unconfirmed
Slack integration	Pass: Slack notifications, /notion create, link previews	Pass (Pack exists; plan needed not confirmed): Slack Pack linked from the Jira Pack page	Pass: Slack app, link previews, /confluence connect
Jira integration	Partial: managed sync needs Business or Enterprise, read-only, no comments or attachments	Partial: Jira Pack on Team/Business and Enterprise only	Pass: Jira macros inside Confluence Cloud (same vendor)
SOC 2	Pass (claimed): SOC 2 Type II on trust center	Pass (claimed): SOC 2 Type 2 listed	Pass (claimed): Confluence Cloud listed under SOC 2

These are vendor claims. I did not read any audit report.

Feature matrix: SSO and API limits

Feature	Notion	Coda / Superhuman Docs	Confluence Cloud
SAML SSO	Yes, Business (pricing page)	Yes, Enterprise only (help)	Yes, via Guard Standard add-on on Standard or Premium; included in Enterprise (Atlassian plans)
SCIM provisioning	Yes, Enterprise (pricing page)	Yes, Enterprise (security page)	Yes, Guard Standard (Atlassian plans, where Guard Standard is the SSO and SCIM add-on)
API rate limit	Per connection: 600/min on Business and Enterprise, 180/min on other plans	Not plan-dependent per user: reads 100 per 6s; writes 10 per 6s; doc-content writes 3 per 10s; listing docs 4 per 6s. A tracker lists 5 per 10s for doc-content writes; I use the vendor's 3	App traffic: points-based, 65,000 points/hour shared global pool by default; API-token traffic stays under burst limits
Docs larger than 125 MB via API	n/a	May not access the API	n/a
Audit logs	Unknown (not checked)	Enterprise only, 12 months via Audit API	Unknown (not checked)

Caveat: Notion's limit is per connection and also has a shared workspace budget. Atlassian's quota covers Forge, Connect and OAuth apps; the two models cannot be compared directly.

Sentiment summary

Not completed. G2, Capterra and TrustRadius returned 403 for all three products, so I have no rating, review count or recurring-theme evidence that meets the three-source rule. I did not use search snippets or memory to fill this gap. Open item: a person with review-site access should pull ratings, counts and dates before a purchase decision.

Your gaps and advantages

Skipped. Acme Docs resolves to a parked domain, so there is nothing to rank. Supply a working product URL to run this section.

Recommendation by use case

Best for the under-$15 SSO constraint with Slack and Jira: Confluence Standard plus Guard Standard, because its base plans cost $5.42 to $10.44 per user (third party) and it has native Jira macros and a Slack app. Confirm the Guard price first.
Best for read-heavy teams with few authors: Coda Pro or Business, because only Doc Makers are billed. It still fails SSO without Enterprise.
Best for flexible docs and databases, if budget allows $20: Notion Business, because it adds SSO and the Jira sync. It fails your price line.

Pilot plan for Confluence:

Run 3 to 4 weeks with one 10 to 20 person team on a trial of Standard plus Guard.
Test cases: SSO login through your identity provider, SCIM deprovision, a Jira issue macro on a spec page, Slack link previews and notifications.
Success criteria: all four pass, and the total quote for plan plus Guard stays under $15 per user.
Check one API script against the rate limits.
Exit point: if the Guard bill or Marketplace add-ons push cost over $15 per user, stop and re-quote Notion Business.

Do next

Ask Atlassian for a written quote showing Standard plus Guard Standard on annual and monthly billing.
Ask Superhuman for the Enterprise price and whether the Slack Pack is on Pro.
Pull review-site ratings manually from G2 and Capterra.
Ask Notion for volume pricing on Business.
Provide a real URL for Acme Docs.

Near misses and open items

Notion: cut on price. It has the best databases story but SSO costs $20.
Coda: cut on SSO tier and Jira Pack tier. Open: live vendor price page, Slack Pack plan, doc-content write limit (3 vs 5 per 10 seconds).
Confluence: open: billing mode behind the displayed prices, Enterprise price, the Guard Standard price.

Coverage

Not reached: Atlassian's own pricing and Guard pricing pages (empty body); G2, Capterra, TrustRadius (403); coda.io and superhuman.com pricing pages (empty body); Wayback captures for Coda and Atlassian (toolbar only). Coda prices come from third-party trackers. Notion's price table was read live on 5 October 2026.

Sources

All checked 5 October 2026.