Can you recommend oligo and construct providers for custom DNA design when sequence accuracy matters?

Yes—if sequence accuracy matters, I’d prioritize providers with tight QC, cloning/assembly verification, and clear error-handling policies rather than just the cheapest synthesis.

Oligo providers

For standard and modified oligos, good accuracy-focused options include:

• IDT (Integrated DNA Technologies)
  Strong reputation for reliable synthesis, fast turnaround, and good QC. Great for standard primers, probes, and many modifications.

• Eurofins Genomics
  Solid for custom oligos and many specialty formats; good global availability.

• Thermo Fisher / GeneArt
  Useful when oligos are part of a larger workflow, though less often my first pick for “best-in-class” oligo-only service.

• LGC Biosearch / Custom oligo vendors
  Particularly good for probe chemistry and specialized fluorescent oligos.

DNA construct / gene synthesis providers

For plasmids, gene synthesis, and larger constructs where correctness is critical:

• GenScript
  One of the best-known choices for custom gene synthesis and construct cloning with verification options.

• Twist Bioscience
  Strong for high-throughput synthesis and complex libraries; often very good sequence fidelity.

• IDT Gene Synthesis / gBlocks / EBlocks
  Excellent for shorter fragments and modular assembly workflows.

• Genewiz / Azenta
  Good for gene synthesis, cloning, and sequencing-backed validation services.

• Thermo Fisher GeneArt
  Established provider for gene synthesis and cloning.

• Synbio Technologies
  Often competitive for custom constructs and cloning services.

What to look for when accuracy is the priority

Choose a provider that offers:

• Sequence-verified clones
• NGS or Sanger validation with raw trace/report access
• Clear guarantee policy for synthesis errors
• Low-error synthesis methods for difficult sequences
• Experience with problematic regions
  e.g., repeats, high GC, hairpins, toxic genes
• Design review support to flag synthesis issues before order submission

Practical recommendations

• For primers/probes/short oligos: start with IDT
• For gene fragments / short constructs: IDT, GenScript, Twist
• For full plasmid or larger construct work: GenScript, Genewiz/Azenta, Twist, GeneArt
• For high-confidence sequence validation: prefer vendors that provide clone-level sequence verification, not just mass-spec or pooled QC

If you want, I can also give you:

1. a ranked shortlist by application (primers, long oligos, genes, plasmids), or
2. a buying checklist for choosing a provider based on error tolerance, turnaround, and budget.