Picks by use caseNoSQL and key-value databases
NoSQL and key-value databases: picks by overall score
Scored with rule v2 on Oct 23, 2026, using only the numbers on this site and facts with a cited source. Referral links, site traffic and clicks are not used. How the score works.
TierDiff's take
None of the three needs a card, all have a free-plan Tokyo region, and none expires. They differ in data model. Upstash is Redis-compatible key-value, with limits on commands and transfer as well as capacity. Firebase and MongoDB Atlas are document databases: Firebase connects straight from apps, while Atlas’s free cluster pauses when unused and has no private endpoints.
The ranking comes from the rule above; this commentary is written by TierDiff and does not affect it.
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1st on TierDiff's overall score for NoSQL and key-value databases
Upstash Redis
74/100Overall score
What adds most to the score: free-tier limits 44 pts, no card to start 15 pts, no time limit 15 pts
Serverless-friendly Redis
Good for: people who want Redis-compatible key-value from runtimes where TCP is restricted. Redis-compatible and reachable from any Redis client, including edge and serverless runtimes where TCP is restricted. The free plan needs no card and has a Tokyo region.
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2nd on TierDiff's overall score for NoSQL and key-value databases
Firebase
65/100Overall score
What adds most to the score: free-tier limits 35 pts, no card to start 15 pts, no time limit 15 pts
Connect straight from your app
Good for: people whose iOS, Android or web apps should read and write data without a server. Cloud Firestore is a NoSQL document database your apps can access directly, and it syncs data to connected devices. It caches data so apps keep working offline.
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3rd on TierDiff's overall score for NoSQL and key-value databases
MongoDB Atlas
56/100Overall score
What adds most to the score: free-tier limits 26 pts, no card to start 15 pts, no time limit 15 pts
To try a document database
Good for: people who want to try MongoDB's document database in a Tokyo region. The free cluster can sit in Tokyo. It pauses automatically after a long idle spell, and each project can have one free cluster. Private endpoints are not available.
Every service and its score
Weights on this page: free-tier limits 60, no card to start 12.5, no time limit 12.5, paid price 15. Paid price is not counted yet: none of the 5 services have a monthly price with a quote from the pricing page, fewer than half. The other weights (85 in total) are scaled up to 100. Each part is scored from 0 to 100, and the overall score is their weighted average.
| Rank | Service | Overall | Free-tier limits | No card to start | No time limit | Paid price |
|---|---|---|---|---|---|---|
| 1 | Upstash Redis | 74 | 63 | 100 | 100 | not counted |
| 2 | Firebase | 65 | 50 | 100 | 100 | not counted |
| 3 | MongoDB Atlas | 56 | 38 | 100 | 100 | not counted |
| 4 | Convex | 32 | 25 | 0not verified | 100 | not counted |
| 5 | Redis Cloud | 29 | 0 | 100 | 100 | not counted |
See the evidence
Where each part of the score comes from: limit values with the quote from the pricing page, and facts with their source, quote and the date we checked them.
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Upstash Redis
1st, overall score 74
Free-tier limits: 63
Database size: 250 MB (4th of 5)
…$0 - Perfect for prototypes and hobby projects. Data Size 250 MB Monthly Bandwidth 10 GB Monthly Commands 500K Start…
upstash.com/pricing/redischecked Oct 23, 2026
Projects / databases: 1 (1st of 1)
…per index | 10K | 1M | 100K | Custom | Max Databases | 1 | 100 | 100 | Custom Features | Supported platforms |…
upstash.com/pricing/redischecked Oct 23, 2026
No card to start: 100
No card needed to start
Upstash does not require a credit card for Free databases.
upstash.com/docs/common/account/add-payment-methodchecked Oct 16, 2026
No time limit: 100
Free tier with no time limit
Paid price: 0not counted
No monthly price with a quote on TierDiff (counts as 0)
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Firebase
2nd, overall score 65
Free-tier limits: 50
Database size: 1 GB (1st of 5)
…pricing Cloud Firestore Standard edition Stored data 1 GiB total No-cost up to 1 GiB total Then Google Cloud…
firebase.google.com/pricingchecked Oct 22, 2026
Projects / databases: no value on TierDiff (counts as 0)
No card to start: 100
No card needed to start
No payment information needed to get started
firebase.google.com/docs/projects/billing/firebase-pricing-planschecked Oct 16, 2026
No time limit: 100
Free tier with no time limit
Paid price: 0not counted
No monthly price with a quote on TierDiff (counts as 0)
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MongoDB Atlas
3rd, overall score 56
Free-tier limits: 38
Database size: 512 MB (2nd of 5)
…learning and exploring MongoDB in a cloud environment. 512MB of storageShared RAMShared vCPU Flex $0.011/hour Build…
mongodb.com/pricingchecked Oct 22, 2026
Projects / databases: no value on TierDiff (counts as 0)
No card to start: 100
No card needed to start
free tier, so you won’t need any payment or credit card information
mongodb.com/resources/products/platform/mongodb-atlas-tutorialchecked Oct 17, 2026
No time limit: 100
Free tier with no time limit
Paid price: 0not counted
No monthly price with a quote on TierDiff (counts as 0)
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Convex
4th, overall score 32
Free-tier limits: 25
Database size: 500 MB (3rd of 5)
…GB-hour) | Storage | Storage Database storage (per GB) | 0.5 GB included ($0.22 per additional GB) | 50 GB included…
convex.dev/pricingchecked Oct 22, 2026
Projects / databases: no value on TierDiff (counts as 0)
No card to start: 0
Not verified yet (counts as 0)
No time limit: 100
Free tier with no time limit
Paid price: 0not counted
No monthly price with a quote on TierDiff (counts as 0)
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Redis Cloud
5th, overall score 29
Free-tier limits: 0
Database size: 30 MB (5th of 5)
…Always $0 Up to 30 MBTry for free Shared cloud deployment 30 MB single DB Best-effort SLA, community support…
redis.io/pricingchecked Oct 23, 2026
Projects / databases: no value on TierDiff (counts as 0)
No card to start: 100
No card needed to start
upgrade a free plan to a paid plan, you need to add a payment method
redis.io/docs/latest/operate/rc/subscriptions/view-essentials-subscriptionchecked Oct 17, 2026
No time limit: 100
Free tier with no time limit
Paid price: 0not counted
No monthly price with a quote on TierDiff (counts as 0)