STEALTHMARK · HEAD TO HEAD

All comparisons ↗

Cat Jam Free vs Callstack Apex

Callstack Apex leads Cat Jam Free by 16.0 points on StealthMark, 49.5 to 33.5. It leads on 7 of the 8 benchmarks with results for both and Cat Jam Free on 1, including Latch. Pixel Canary scores higher on Newton's Mirror, with its largest category advantage in camera and placement.

See the difference ↘
Model guide ↗
Model guide ↗

Overall StealthMark

33.5/100Overall rank 40/53
49.5/100Overall rank 18/53

General Intelligence

27.7/100
40.4/100

Visual Intelligence

43.0/100
59.6/100

Reasoning efficiency

On every task, result quality and reasoning tokens are each compared with all measured models and weighed equally. Each dot is one model.

Single-step reasoning Result quality weighed against reasoning tokens on a single problem

Multi-step reasoning Result quality weighed against reasoning tokens across connected steps, as in agentic workflows

Open or local

NeitherApache-2.0

BENCHMARK BY BENCHMARK

Where each model leads

  • Cat Jam Free
  • Callstack Apex
  • Other models
  • Median

DATASHEET

Specs and pricing

  • Cat Jam Free
  • Callstack Apex
  • Other models
  • Median
PricePer 1M output tokens, input below
Cat Jam Free: No list priceCallstack Apex: $3$0.50 input
Context windowTokens per request, max output below
Cat Jam Free: Not publishedCallstack Apex: 256K
Output speedTokens per second, our measurement
Cat Jam Free: Not measuredCallstack Apex: 255tokens/s
Developer
Not publishedCallstack
Released
Not published1 Oct 2026
Origin
Not publishedPoland
Input → output
Not publishedText → text
Architecture
Not publishedQwen foundation with Callstack domain post-training for React and React Native

Full datasheets, every price and sourceCallstack Apex ↗

Anticipating threats and planning ahead. Collect coins while avoiding ghosts. Ghosts move before the player each turn, and collisions cost a life. 3 levels in sequence, up to 66 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Cat Jam Free 33.8/100Rank 26/47

Survived 1 of 3
Foresight: complete playing field
Level 39 ptsTurn 20 / 20

Points per level

LevelCat Jam FreeCallstack Apex
Level 1Second Thoughts
5 ptsOut of lives
No run
Level 2Pressure Pot
6 ptsOut of lives
No run
Level 3Hide or Flight
9 ptsSurvived
No run

Cooperative planning and learning from experience. Coordinate two robots to push numbered cores onto matching sockets. Pressure plates hold doors open; moving either robot uses one turn. 5 levels in sequence, up to 152 turns in total. Earlier moves and outcomes carry forward, testing learning across levels.

Cat Jam Free 33.9/100Rank 33/48

Cleared 2 of 5
Latch: complete playing field
Level 56 ptsTurn 25 / 40

Callstack Apex 100.0/100Rank 40/481 of 5 levels

1 of 5 played
Latch: complete playing field
Level 15.2 ptsTurn 6 / 12

Points per level

LevelCat Jam FreeCallstack Apex
Level 1Hold the door
5.2 ptsCleared
5.2 ptsCleared
Level 2Crossfeed
9.8 ptsCleared
Pending
Level 3Relay vault
10 ptsFinished early
Pending
Level 4Passing bay
10.8 ptsFinished early
Not played
Level 5Second thoughts
6 ptsFinished early
Not played

Newton's Mirror

Same task instructions

Physics, perspective and recursive reflections, tested together. Explore the test ↗

The judgment

Cat Jam Free

The image conveys a supported central sphere, separate black paint and crimson below cyan. Its contact and transport story is partially resolved. The exterior cutaway camera and largely missing mirror system dominate the limitations; isolated discs and smooth highlights provide little coherent optical structure.

Callstack Apex

The principal sphere placement and paint contact sequence are supported. Isolated sphere and panel images provide limited optical structure, but missing lateral chains and side-floor continuations prevent a coherent repeating mirror room. The main and reflected spheres lack ordered curved nested imagery, while sparse planar emitter images and incomplete spherical emitter mapping leave most of the reflection system unsupported.

Score breakdown

CategoryCat Jam FreeCallstack Apex
State at 600 ms14.0/2520.0/25
Camera and placement4.0/1513.0/15
Reflections3.5/12010.0/120
Materials and scale4.0/107.0/10
Floor-damage reward0.0/100.0/10

Benchmark task

A spinning metal sphere and paint in a mirrored room test physical reasoning, perspective and consistency across repeated reflections.

Selfie

Different task instructions

Visual construction and creative interpretation.

The judgment

Cat Jam Free

A coherent, restrained cat illustration captures the pale palette and intent eyes. Its central expressive requirement—the committed forward-and-down neck bob—is insufficiently articulated. Simple geometry, faint paw construction and minimal surface detail limit the physical presence and finish.

Callstack Apex

The cheerful yellow bird, cream eyes, orange features and miniature teal console closely match the brief. Clean block edges, restrained colors and soft shadows create an appealing composition. The body reads more like a gridded disc than a fully cubic sphere, and the outlined left wing has limited volume. The right wing reaches the cyan block, though its grip is ambiguous.

Score breakdown

CategoryCat Jam FreeCallstack Apex
Task & likeness5.5/108.5/10
Anatomy & construction5.5/107.0/10
Space & placement6.0/107.5/10
Light & reflections6.0/107.5/10
Purposeful detail4.0/107.5/10
Artistry & character5.5/107.0/10
Materials & effects5.0/107.0/10
Visual integrity6.5/107.5/10

Benchmark task

Cat Jam Free

An ivory cat nods intently to music beside a tiny speaker. The scene tests feline anatomy, movement conveyed through a still pose and the contrast between pale fur and woven fabric.

Callstack Apex

A rounded bird built from small cubes explores a miniature machine. The scene tests block construction, expressive proportions, contact and soft lighting.

Mona Lisa

Different task instructions

Precise visual recall and portrait reconstruction.

The judgment

Cat Jam Free

The portrait is recognizable and cleanly assembled, but replication remains basic. Its frontal symmetry, elongated silhouette, simplified facial likeness and unresolved hands differ markedly from the original. Modest skin gradients provide volume, while clothing and landscape rely on broad, flat shapes.

Callstack Apex

The framed portrait recalls Mona Lisa through dark hair, folded arms and a hazy landscape. Replication is limited by wide, staring eyes, an elongated neck and a downturned mouth. The overlapping hands lack convincing finger and wrist construction. Soft tonal shading suggests volume, but pervasive blur obscures clothing, landscape and anatomical detail.

Score breakdown

CategoryCat Jam FreeCallstack Apex
Task & likeness2.5/103.5/10
Anatomy & construction2.0/104.0/10
Space & placement4.0/104.5/10
Light & reflections3.5/106.0/10
Purposeful detail3.0/104.5/10
Artistry & character3.0/104.5/10
Materials & effects2.5/105.5/10
Visual integrity5.5/105.5/10

Benchmark task

An SVG interpretation of the Mona Lisa tests facial likeness, anatomy and the composition of a familiar portrait.

Beach

Different task instructions

Creativity, perspective and visual beauty.

The judgment

Cat Jam Free

The scene clearly supplies the requested beach subjects and playful activity. Clean silhouettes and warm gradients support readability, but elementary drawing, ambiguous parasol construction, weak grounding and a rigid sun reflection limit its depth and finish.

Callstack Apex

A cohesive sunset beach illustration with lively wildlife, playful accents, and an appealing warm-to-purple palette. Palm framing and the aligned sun reflection organize the scene, while connected silhouettes keep the activities readable. Schematic joints, ambiguous dolphin junctions, loosely matched reflections, and repetitive surface marks limit construction, lighting coherence, and material depth.

Score breakdown

CategoryCat Jam FreeCallstack Apex
Task & likeness7.0/108.5/10
Anatomy & construction4.5/104.5/10
Space & placement4.5/107.5/10
Light & reflections4.0/105.5/10
Purposeful detail4.0/107.5/10
Artistry & character4.5/106.5/10
Materials & effects4.5/107.0/10
Visual integrity5.5/104.0/10

Benchmark task

A busy shoreline at sunset tests scene composition, animal forms and the relationship between light and water reflections.

Ground Truth

Same task instructions

Physical reasoning, light and visual reconstruction.

The judgment

Cat Jam Free

This benchmark has not been assessed yet.

Callstack Apex

This benchmark has not been assessed yet.

Benchmark task

A plank, computer mouse and blueberry in a steel room test physical stability, spatial relationships, materials and lighting.

Raccoon

Multiple instruction versions

Scene composition and interacting subjects.

The judgment

Cat Jam Free

An appealing cartoon demonstrates the back-riding arrangement through expressive faces and clean shapes. Uncertain steering contact, indistinct deck support and weak hull-water interaction limit physical coherence. Smooth gradients add volume, but simple rounded construction and sparse material detail constrain complexity and finish.

Callstack Apex

The raccoon clearly rides the dog's back, and the dog's paws reach the jet ski controls. Expressive faces, a sweeping tail and a strong sunset composition give the illustration character. Limbs remain connected, but the dog's foreleg joints and vehicle seating are loosely constructed. Angular splashes convey speed more successfully than convincing water displacement; lighting and reflections remain decorative.

Score breakdown

CategoryCat Jam FreeCallstack Apex
Task & likeness6.0/109.0/10
Anatomy & construction5.0/107.0/10
Space & placement5.0/107.5/10
Light & reflections5.0/107.0/10
Purposeful detail6.0/108.5/10
Artistry & character5.0/107.5/10
Materials & effects5.0/107.0/10
Visual integrity4.5/108.0/10

Benchmark task

A jet-ski scene pairs a canine driver with a raccoon passenger. It tests the placement and contact of interacting subjects, along with vehicle construction.

Pelican

Different task instructions

Subject construction and spatial relationships.

The judgment

Cat Jam Free

A coherent cartoon with readable bicycle placement, controlled outlines and modest surface shading. The separated-looking upper bill weakens pelican likeness; schematic limbs, uncertain gripping contact and simplified mechanics constrain construction. Opaque wheel interiors flatten spatial relationships. Limited feather complexity and directional lighting keep the finish modest.

Callstack Apex

An appealing cartoon with a distinctive pelican, expressive eye, warm bill and carefully drawn bicycle wheels. The wing reaches the handlebar, but the feet do not clearly engage the pedals, weakening the riding mechanics. Layered hills create depth; limited ground shadows weaken contact. Clean curves and purposeful feather details give the illustration polish.

Score breakdown

CategoryCat Jam FreeCallstack Apex
Task & likeness7.0/108.5/10
Anatomy & construction5.0/106.5/10
Space & placement6.0/107.5/10
Light & reflections5.0/107.5/10
Purposeful detail5.5/108.0/10
Artistry & character5.5/108.0/10
Materials & effects6.5/107.5/10
Visual integrity6.5/108.0/10

Benchmark task

A cycling pelican tests anatomy, riding posture and contact between the bird and the bicycle.