ReLLM vs sizeless: Features, Pricing & Which Is Better (2026)
A side-by-side comparison of ReLLM and sizeless — features, pricing, and ideal use cases — to help you decide which AI tool fits your workflow.
ReLLM
r2d4
Python library that enforces exact structured outputs from LLM completions by masking logits to match regex patterns.
Key features
- Token-level Pre-filtering: Tests each possible next-token completion against a partial regular expression and prevents tokens that would break the pattern from being generated by masking their logits.
- Partial-Regex Evaluation: Evaluates potential continuations incrementally using partial regular expressions so the generation process can be constrained at every step to enforce complex formats.
- Logit Masking Compatibility: Operates by masking logits rather than post-filtering, enabling deterministic enforcement of structure within standard decoding loops (e.g., greedy, top-k) when the model exposes logits.
- Structured Output Enforcement: Ensures outputs conform to strict formats such as JSON arrays or other schema-like regex patterns, reducing the need for downstream parsing and correction.
- Easy Installation and Examples: Distributed as a Python package (pip install rellm) with repository examples demonstrating common patterns and prompt setups for extracting structured data.
- Hosted API Reference: Notes availability of a hosted Regex Completion API (Thiggle Regex Completion API) for users seeking a managed service rather than self-hosted integration.
- Regex-driven pre-generation filtering that tests completions against a partial pattern per token
- Masks logits for disallowed tokens so the language model cannot generate non-matching outputs
- Designed to produce exact structured outputs (e.g., JSON, constrained formats) from LMs
- Pip-installable Python package (pip install rellm) with repository examples
- References a hosted API option (Thiggle Regex Completion API) for managed usage
Best for
- Reliable JSON Extraction: Force LLM responses to produce valid JSON arrays or objects (e.g., lists of items) so downstream systems can parse them without additional validation.
- Formatted Data Generation: Ensure generated outputs match strict formats like CSV rows, phone numbers, or fixed field templates required by legacy systems or ingestion pipelines.
- Schema-Constrained APIs: Integrate ReLLM into production inference to guarantee responses conform to expected regex-based schemas for webhooks, microservices, or data pipelines.
- Testing and Validation of LLM Behavior: Use regex constraints to probe and validate model behavior (e.g., detect memorized patterns or biased outputs) by restricting generations to specific patterns.
- Safe Prompting for Automation: Prevent hallucinated or malformed outputs in automation workflows (chatbots, document generation) by constraining possible tokens to only those that maintain the format.
- Hybrid Hosted or Self-Hosted Deployment: Use the open-source library in local inference stacks or adopt referenced hosted Regex Completion APIs for managed deployments where self-hosting isn't desired.
- Enforcing JSON or other structured output formats from LLMs for reliable parsing
- Constraining model generation to domain-specific patterns (IDs, phone numbers, codes)
- Validating or sanitizing LM outputs in pipelines that require strict formatting
- Research and testing of model behavior under constrained decoding
- Providing deterministic or format-guaranteed completions for integrations and APIs
sizeless
sizeless
Turns a smartphone video of an open trench into a centimetre-accurate 3D point cloud, CAD as-built plan and GIS-ready digital twin of buried utilities.
Key features
- Smartphone capture: Field crews record an open trench with a standard iPhone Pro — no specialist scanning hardware and no separate surveying appointment
- Centimetre-accurate point clouds: Reconstruction algorithms developed at ETH Zurich build a high-resolution 3D point cloud of the excavation from the video alone
- Standards-compliant CAD output: Generates as-built plans in DWG and DXF, with couplings and pipe runs identified and measurements simplified
- 3D digital twin and GIS export: Produces a model of the pipe route including building entries that drops into existing GIS systems
- Works without GPS: Captures basement sections and building entry points where GNSS-based surveying fails
- Immediate backfilling: Because capture takes minutes, trenches close right after filming instead of waiting on a survey crew
- Documentation in about 72 hours: Complete records arrive weeks earlier than conventional surveying, enabling prompt connection billing
- Third-party utility capture: Records crossing utilities and as-laid geometry as unbroken 3D evidence, replacing hand sketches
Best for
- A utility network operator documenting residential service connections without booking a surveyor for every site
- A contractor closing a trench the same day instead of leaving it open pending a survey appointment
- Capturing a building entry point in a basement where GPS-based surveying cannot get a fix
- A district heating project producing as-built DWG plans for regulatory sign-off
- Spotting a laying error in the 3D point cloud before backfilling, while the fix is still cheap
- Feeding as-built pipe geometry into a GIS system for long-term network maintenance planning