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Comparison · DevOps

Psi4 vs Tigris

A side-by-side editorial comparison of Psi4 and Tigris — release velocity, themes, recent moves, and the top alternatives to consider.

Psi4 vs Tigris: at a glance

FeaturePsi4Tigris
SectorDevOpsDevOps
Velocity score0.05.0
Sparks · 30d00
Top themesquantum-chemistry, coupled-cluster, qcschema, python-packagingobject-storage, foundationdb, geo-replication, s3-compatibility
Last editorial update9d ago15h ago
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What is Psi4?

Psi4 is closing the gap with ORCA on the methods that decide which code a lab installs

Psi4 ships a major version roughly annually with a trail of conda-compatibility patch releases behind each one. The 1.11 cycle is the most competitively pointed in the window: DLPNO-CCSD and DLPNO-CCSD(T) become callable methods, with cutoffs deliberately tuned to match ORCA, and ZORA arrives for scalar-relativistic core Hamiltonians. Around the science, the project spends heavily on Python-ecosystem plumbing — QCSchema v2, Python 3.14 support, and the QCArchive dependency chain that most of its patch releases exist to unbreak.

Read the full Psi4 trajectory →

What is Tigris?

Tigris keeps publishing its architecture, and the newest post opens up the storage engine itself.

This feed is Tigris's engineering blog, and it alternates between protocol critique and descriptions of how the product answers it. The most recent post opens the internals: how Tigris composes ACID metadata, global placement, caching, replication, and background work on FoundationDB into a multi-region object store. Before it came the Recycle Bin — deletion of objects and buckets on top of immutable storage in an active-active geo-replicated database — plus two posts dissecting SigV4 and presigned URLs, and one on agent-native onboarding through tigris init --agent.

Read the full Tigris trajectory →

Psi4 vs Tigris: editorial side-by-side

P
Psi4
DEVOPS
0.0

Psi4 is closing the gap with ORCA on the methods that decide which code a lab installs

◆ Current state

Psi4 ships a major version roughly annually with a trail of conda-compatibility patch releases behind each one. The 1.11 cycle is the most competitively pointed in the window: DLPNO-CCSD and DLPNO-CCSD(T) become callable methods, with cutoffs deliberately tuned to match ORCA, and ZORA arrives for scalar-relativistic core Hamiltonians. Around the science, the project spends heavily on Python-ecosystem plumbing — QCSchema v2, Python 3.14 support, and the QCArchive dependency chain that most of its patch releases exist to unbreak.

◆ Where it's heading

Two things are being built at once. Scientifically, the code is filling in the local-correlation and relativistic methods that users otherwise leave for commercial packages, plus external-potential and embedding machinery that makes Psi4 usable as a QM engine inside larger workflows. Structurally, it is betting on the QCArchive stack — qcelemental, qcengine, qcmanybody, optking, qcfractal — which delivers interoperability but also means a Python packaging change downstream can force a release, as 1.10.1 and 1.10.2 both did.

◆ Prediction

The DLPNO work landed as energies only, so analytic gradients for DLPNO-CCSD are the natural next step. Expect at least one more 1.11.x patch driven by the QCFractal and pydantic constraints that the 1.11 notes flag as still unresolved for Python 3.14.

T
Tigris
DEVOPS
5.0

Tigris keeps publishing its architecture, and the newest post opens up the storage engine itself.

◆ Current state

This feed is Tigris's engineering blog, and it alternates between protocol critique and descriptions of how the product answers it. The most recent post opens the internals: how Tigris composes ACID metadata, global placement, caching, replication, and background work on FoundationDB into a multi-region object store. Before it came the Recycle Bin — deletion of objects and buckets on top of immutable storage in an active-active geo-replicated database — plus two posts dissecting SigV4 and presigned URLs, and one on agent-native onboarding through tigris init --agent.

◆ Where it's heading

The writing is doing product work. Each protocol post establishes a problem — SigV4's canonicalization and clock skew, presigned URLs as deliberate replay attacks, S3 egress pricing on ClickHouse restores — and positions Tigris behavior as the answer, which makes the blog a migration funnel rather than a changelog. The architecture post is a different move: publishing the FoundationDB composition is a credibility play aimed at buyers who need to believe a newer object store can hold multi-region data.

◆ Prediction

Expect the protocol-critique-then-Tigris-answer format to continue, with the egress-cost framing recurring as the clearest paid migration path. Feature announcements will likely stay embedded in essays rather than appearing as release notes.

Alternatives to Psi4 and Tigris

Other DevOps products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either Psi4 or Tigris.

See all Psi4 alternatives → · See all Tigris alternatives →

Recent activity from Psi4 and Tigris

Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.

  1. 2d agoTigrisBuilding a global object store on FoundationDB
  2. 9d agoTigrisExtending immutability: deletion without losing data
  3. 14d agoTigrisSigV4 authentication is surprisingly complicated
  4. 23d agoTigrisHumans don't install software themselves anymore, their agents do
  5. 1mo agoTigrisThe Most Expensive ClickHouse Query Is the Restore
  6. 1mo agoTigrisPresigned URLs are technically a security vuln
  7. 1mo agoPsi4Psi4 1.11 makes DLPNO-CCSD(T) callable and matches ORCA's cutoffs
  8. 2mo agoPsi4Psi4 1.10.2 unbreaks adcc with QCFractal 0.65
  9. 2mo agoPsi4Psi4 1.10.1 widens conda pins, fixes path-advisor solving
  10. 11mo agoPsi4Psi4 1.10 adds MP2-F12, SAPT0-D4M and an LS-THC Python interface
  11. 2y agoPsi4Psi4 1.9 adds unrestricted-LDA analytic Hessians and new SCF guesses
  12. 2y agoPsi4Psi4 1.9.1 pins pytest 7 and prefers released libint

Frequently asked questions

What is the difference between Psi4 and Tigris?

They serve adjacent needs but don't currently overlap on shipped themes. Tigris is currently shipping more aggressively (velocity 5.0 vs 0.0), with 0 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.

Is Psi4 better than Tigris?

Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Tigris is currently shipping more aggressively (velocity 5.0 vs 0.0), with 0 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other DevOps products to evaluate alongside.

What are the best alternatives to Psi4?

Top Psi4 alternatives in DevOps are ranked by recent ship velocity. Browse the "Psi4 alternatives" section above for the current picks, or visit /alternatives/psi4 for the full list with editorial commentary on each.

What are the best alternatives to Tigris?

Top Tigris alternatives in DevOps are ranked by recent ship velocity. Browse the "Tigris alternatives" section above for the current picks, or visit /alternatives/tigris for the full list with editorial commentary on each.